Kinematic?Analysis?of?the?Collected?and?Extended?Jog?and?Lope?? of?the?Stock?Breed?Western?Pleasure?Horse? ? by? ? Joanna?Elizabeth?Shroyer? ? ? ? ? A?dissertation?submitted?to?the?Graduate?Faculty?of? Auburn?University? in?partial?fulfillment?of?the? requirements?for?the?Degree?of? Doctor?of?Philosophy?? ? Auburn,?Alabama? December?13,?2010? ? ? ? ? Keywords:??kinematics,?stock?breed?western?pleasure,?jog,?lope? ? Copyright?2010?by?Joanna?Elizabeth?Shroyer?? ? ? Approved?by? ? Wendi?H.?Weimar,?Chair,?Associate?Professor?of?Kinesiology? Robert?Gillette,?Director?of?Animal?Health?and?Performance?Program? David?D.?Pascoe,?Professor?of?Kinesiology? Elizabeth?L.?Wagner,?Assistant?Professor?of?Animal?Sciences? ? ii Abstract? ? ? Scientific? research? concerning? stock? breed? western? pleasure? horses? is? limited.??Therefore?the?purposes?of?this?investigation?were?to?determine?if?stock? breed? western? pleasure? horses? 1)? alter? stride? length? independently? of? stride? duration?for?the?collected?and?extended?jog?and?lope;?2)?perform?the?extended?jog? and?lope?as?a?gait?that?more?closely?follows?guidelines?set?forth?by?major?stock? breed?associations?for?western?pleasure?competition?than?does?the?collected?jog? and? lope;? 3)? maintain? a? more? correct? head? and? topline? carriage? during? the? extended?jog?and?lope?than?during?the?collected?jog?and?lope,?and?4)?perform?the? extended?jog?and?lope?with?a?more?natural?way?of?going?thereby?reducing?risk?of? joint?injury?and?trauma?compared?to?the?collected?jog?and?lope.???? Reflective?markers?were?placed?over?seven?points?on?the?lateral?side?of?the? left?and?right?fore?and?hindlimbs?as?well?as?the?medial?aspect?of?the?coffin?bone;? additional? markers? tracked? the? temporal? bone? and? vertebral? column.??Three? successful?strides?of?each?gait?were?analyzed?using?the?Peak?Motus ? ?1994?2004? motion? analysis? system? (Peak? Performance? Technologies,? Inc.,? Englewood,? iii Colorado,? USA).???Digitization,? transformation,? smoothing,? and? normalization? techniques?followed?standard?kinematic?techniques.??? Results?indicate?that?all?gaits?were?performed?as?four?beat?stepping?gaits? with?diagonal?couplets?and?a?lateral?footfall?sequence?with?the?exception?of?the? right? lead? collected? lope,? which? exhibited? a? diagonal? footfall? sequence.??Stock? breed?western?pleasure?horses?do?not?alter?stride?length?independently?of?stride? duration? during? the? jog? or? the? lope.??Further,? the? extended? jog? more? closely? followed?the?guidelines?set?forth?by?major?stock?breed?associations?for?western? pleasure?competition?than?did?the?collected?jog,?however?the?extended?lope?did? not? more? closely? follow? guidelines? than? did? the? collected? lope.??Horses?? head? carriage? and? topline? did? not? more? closely? follow? gait? performance? guidelines? during?the?extended?jog?or?lope?as?horses?maintained?a?level?topline?during?both? the?extended?and?collected?jog?but?did?not?maintain?a?level?topline?during?the? collected? or? extended? lope.??It? was? concluded? that? continuing? gait? definition? transformations? by? more? accurately? describing? the? jog? and? lope? as? four?beat? stepping?gaits?without?visible?separation?of?the?diagonal?pairs?and?to?encourage? even? greater? forward? motion? than? was? seen? in? the? present? study? should? theoretically?reduce?joint?injury?and?trauma?to?the?stock?breed?western?pleasure? horse?while?maintaining?proper?performance?of?the?gaits.??? iv Dedication? ? ? I?would?like?to?dedicate?this?work?to??Nick??who?has?continued?his?dam?s? influence? in? my? life? and? allows? me? first? hand? knowledge? of? the? stock? breed? performance? industry.???Nick?? represents? all? stock? breed? western? pleasure? horses,?as?they?are?truly?the?most?misunderstood?and?misjudged?athletes?of?the? equine?industry.??To?your?trainers,?breeders,?keepers,?riders,?and?owners?who? cannot? possibly? understand? the? depth? of? your? heart? and? commitment? to? their? own? self? edification? through? recognition? and? blue? ribbons,? I? offer? this? slight? glimpse?into?your?little?understood?way?of?going.??? ? ? ? ? ??? ? ? ? ? v Acknowledgments? ? ? ? The?author?expresses?her?sincere?gratitude?to?numerous?people?for?their? part?in?the?development?of?this?dissertation.??A?multitude?of?thanks?is?due?to?Dr.? Wendi? Weimar? for? providing? direction,? mentorship,? expertise,? and? friendship? throughout?my?doctoral?program.??Appreciation?is?also?due?to?the?other?members? of?my?dissertation?committee?Dr.?Robert?Gillette,?Dr.?David?Pascoe,?and?Dr.?Betsy? Wagner?for?their?guidance?and?support?throughout?this?project?as?well?as?to?Dr.? Cindy? McCall? for? graciously? agreeing? to? serve? as? the? outside? reader.??Data? collection?would?not?have?been?possible?without?the?help?of?my?research?team? including?Dr.?Wendi?Weimar,?Dr.?Betsy?Wagner,?Dr.?Robert?Gillette,?Dr.?Justin? Shroyer,?Dr.?Josh?Bruce,?Ande?Sumner,?Ashley?Bruce,?Casey?Gates,?and?Oluremi? Onifade;?your?help?was?indispensable?and?greatly?appreciated.??Further?thanks? are?extended?to?Steve?Tidwell?and?Kimberly?Tidwell?of?Tidwell?Training?Center,? Summer?Salter?of?Summer?Salter?Show?Horses,?and?Kyle?Grant?of?Kyle?Grant? Show?Horses?in?Tallassee,?Alabama?for?access?to?the?horses?used?in?this?project.?? Their?dedication?to?improvements?in?training?and?showing?of?western?pleasure? performance?horses?is?unequalled.??Credit?is?also?due?to?the?Auburn?University? vi Veterinary? Sports? Medicine? program? including? Sherry? Johnston? and? Dr.?Craig? Angle? for? allowing? me? access? to? and? teaching? me? how? to? make? use? of? the? movement?analysis?software?utilized?in?this?project.??I?must?also?thank?Dr.?Nels? Madsen? from? the? Department? of? Mechanical? Engineering? for? his? input? and? assistance?with?mathematical?processes?that?were?vital?to?the?completion?of?this? work.??Continued?thanks?are?extended?to?my?parents,?Richard?and?Beth?Booker,? for?their?unending?support?of?my?equine?passion?and?confidence?in?my?success;?I? would?not?be?where?I?am?today?without?you.??To?my?husband,?Justin?Shroyer,? thank? you? is? not? enough? for? your? love? and? support? throughout? this? process.?? Finally,?I?would?like?to?thank?my?Lord?and?Savior,?Jesus?Christ,?for?honoring?His? promise?in?Psalm?46?to?be?my?refuge?and?my?strength.??? ? ? ? ? ? ? ? ? ? ? ? vii Table?of?Contents? ? ? Abstract..............................................................................................................................ii? Dedication........................................................................................................................iv? Acknowledgments?..........................................................................................................v? List?of?Tables..................................................................................................................... x? List?of?Figures................................................................................................................xvi? List?of?Abbreviations..................................................................................................xxvi? Introduction??.....................................................................................................................1? ? Stock?Breed?Horses?? .............................................................................................1? ? Western?Pleasure??.................................................................................................3? ? Statement?of?the?Problem...................................................................................11? ? Purpose?of?the?Study..........................................................................................14? ? Hypotheses...........................................................................................................16? ? Operational?Definitions......................................................................................16? Literature?Review??..........................................................................................................26? Defining?Gaits?Through?Kinematics ................................................................27? Head?Carriage......................................................................................................58? viii Injuries..................................................................................................................61? Summary..............................................................................................................63? Materials?and?Methods?? ................................................................................................65? Animals.................................................................................................................66? Recording?Techniques........................................................................................68? Data?Collection....................................................................................................71? Data?Analysis.......................................................................................................72? Statistics................................................................................................................76? Results??.............................................................................................................................79? Collected?Jog........................................................................................................80? Extended?Jog........................................................................................................87? Collected?versus?Extended?Jog..........................................................................93? Collected?Lope.....................................................................................................98? Extended?Lope...................................................................................................121? Collected?versus?Extended?Lope ....................................................................145? Discussion?? ....................................................................................................................153? Collected?and?Extended?Jog ............................................................................154? Collected?and?Extended?Lope.........................................................................168? Injuries................................................................................................................181? Summary............................................................................................................185? ix Conclusion?? ...................................................................................................................189? ? Collected?and?Extended?Jog ............................................................................189? ? Collected?and?Extended?Lope.........................................................................192? ? Injuries................................................................................................................194? ? Future?Research.................................................................................................195? References ......................................................................................................................196? Appendix........................................................................................................................204? ? ? ? ? ? ? ? ? x List?of?Tables? ? Table? Page? ? 1.1? Scientific?classification?of?equine?gaits???right?hind?(RH),?right?fore?? ? (RF),?left?hind?(LH),?and?left?fore?(LF)..............................................................22? ? 1.2??????Anatomical?and?common?joint?names?for?all?joints?analyzed?in?the?? ?????current?study?(Kainer?and?McCracken?1998).??Common?joint?names?????? ?????will?be?used?in?order?to?promote?simplicity?and?clarity.................................24? 2.1???????Means?(??s.d.)?for?stride?duration?(ms)?and?forelimb?stance?(%)?of?the?? ????????????fox?trot?as?performed?by?the?Missouri?Fox?Trotter?and?jog?as?performed?? by the?stock?breed?western?pleasure?horse?(Clayton?and?Bradbury?1995;? Nicodemus?and?Booker?2007;?Nicodemus?and?Clayton?2001a;?Nicodemus? and?Clayton?2003) ...............................................................................................46 ? 3.1? Subject?information?on?research?animals?including?randomly?assigned?? horse?number,?age?(years),?gender?(M?=?mare,?G?=?gelding),?height?? (meters),?weight?(kilograms),?and?breed?registry?(AQHA?=?American? Quarter?Horse?Association,?PHBA?=?Palomino?Horse?Breeders?? ? Association;?APHA?=?American?Paint?Horse?Association)...........................67? 4.1?? Means?(??s.d.)?for?stance?durations?(s)?for?the?following?limbs?of?each?? stock?breed?western?pleasure?horse?(Subject?1?6)?at?the?collected?jog:?? ? right?hind?(RH),?left?hind?(LH),?right?fore?(RF),?and?left?fore?(LF)...............81? 4.2???? Means?(??s.d.)?for?swing?durations?(s)?for?the?following?limbs?of?each?? stock?breed?western?pleasure?horse?(Subject?1?6)?at?the?collected?jog:?? right?hind?(RH),?left?hind?(LH),?right?fore?(RF),?and?left?fore?(LF)?..............82 ? 4.3? Means?(??s.d.)?for?peak?flexion?and?extension?joint?angles?(deg)?measured?? ????????????on?the?flexor?side?of?the?joint?and?range?of?motion?(ROM)?(deg)?for?fore?? ? and?hindlimbs?at?the?collected?jog....................................................................85? ? ? xi Table?????????????Page? ? 4.4???? Means?(??s.d.)?for?stance?durations?(s)?for?the?following?limbs?of?? each?stock?breed?western?pleasure?horse?(Subject?1?6)?at?the?? extended?jog:?right?hind?(RH),?left?hind?(LH),?right?fore?(RF),?and?? left?fore?(LF) .........................................................................................................88? ? 4.5? Means?(??s.d.)?for?swing?durations?(s)?for?the?following?limbs?of?each?? stock?breed?western?pleasure?horse?(Subject?1?6)?at?the?extended?? jog:?right?hind?(RH),?left?hind?(LH),?right?fore?(RF),?and?left?? fore?(LF)................................................................................................................89 ? 4.6???????Means?(??s.d.)?for?peak?flexion?and?extension?joint?angles?(deg)?measured?? on?the?flexor?side?of?the?joint?and?range?of?motion?(ROM)?(deg)?for?? fore?and?hindlimbs?at?the?extended?jog?..........................................................92? ? 4.7?? Statistically?significant?different?(P?0.05)?means?(??s.d.)?for?temporal?? and?linear?variables?of?stride?length?(m),?stride?duration?(s),?? velocity?(m/s),?vertical?excursion?of?the?hip?(m),?diagonal?? advanced?placement?(s),?and?diagonal?bipedal?limb?support?for?stock?? breed?western?pleasure?horses?at?the?collected?and?extended?jog?? (LH???left?hind,?LF???left?fore,?RH???right?hind,?RF???right?fore)..................96?? ? 4.8? Statistically?significant?(P?0.05)?means?(??s.d.)?for?angular?variables?(deg)?? of?peak?flexion,?peak?extension,?and?range?of?motion?(ROM)?for?stock?? breed?western?pleasure?horses?at?the?collected?and?extended?jog?..............97?? ? ?4.9?? Means?(??s.d.)?for?stance?durations?(s)?for?the?following?limbs?of?? each?stock?breed?western?pleasure?horse?(Subject?1?6)?at?the?? right?lead?collected?lope:?right?hind?(RH)?and?left?hind?(LH)....................100?? ? ?4.10? Means?(??s.d.)?for?swing?durations?(s)?for?the?following?limbs?of?each?? ? stock?breed?western?pleasure?horse?(Subject?1?6)?at?the?right?lead?? ? collected?lope:?right?hind?(RH),?left?hind?(LH),?right?fore?(RF),?and?left?? fore?(LF)?.............................................................................................................101? ? ?4.11? Means?(??s.d.)?for?left?and?right?lateral?and?diagonal?advanced?? placements?and?lift?offs?(s)?for?stock?breed?western?pleasure?horses?? at?the?right?lead?collected?lope:??left?lateral?=?LF?LH,?right?lateral?=?? RF?RH,?left?diagonal?=?RF?LH,?and?right?diagonal?=?LF?RH......................101? xii Table?? Page? ? 4.12? Means?(??s.d.)?for?limb?support?phases?as?a?percent?(%)?of?stride?? for?stock?breed?western?pleasure?horses?at?the?right?lead?collected?? lope?.....................................................................................................................103? ? 4.13?? Means?(??s.d.)?for?peak?flexion?and?extension?joint?angles?(deg)?measured?? on?the?flexor?side?of?the?joint?and?range?of?motion?(ROM)?(deg)?for?? fore?and?hindlimbs?at?the?right?lead?collected?lope:?right?hind?(RH),?? left?hind?(LH),?right?fore?(RF),?and?left?fore?(LF)..........................................104? ? 4.14? Means?(??s.d.)?for?stance?durations?(s)?for?the?following?limbs?of?? each?stock?breed?western?pleasure?horse?(Subject?1?6)?at?the?left?lead?? collected?lope:?right?hind?(RH)?and?left?hind?(LH) ......................................112? ? ?4.15? Means?(??s.d.)?for?swing?durations?(s)?for?the?following?limbs?of?? each?stock?breed?western?pleasure?horse?(Subject?1?6)?at?the?left?lead?? collected?lope:?right?hind?(RH),?left?hind?(LH),?right?fore?(RF),?and?left?? fore?(LF)..............................................................................................................113? ? ?4.16? Means?(??s.d.)?for?left?and?right?lateral?and?diagonal?advanced?? placements?and?lift?offs?(s)?for?stock?breed?western?pleasure?horses?at?? the?left?lead?collected?lope:??left?lateral?=?LF?LH,?right?lateral?=?? RF?RH,?left?diagonal?=?RF?LH,?and?right?diagonal?=?LF?RH?.....................113? ? ?4.17? Means?(??s.d.)?for?limb?support?phases?as?a?percent?(%)?of?stride?? for?stock?breed?western?pleasure?horses?at?the?left?lead?collected?lope....115?? ? ?4.18? Means?(??s.d.)?for?peak?flexion?and?extension?joint?angles?(deg)?measured?? on?the?flexor?side?of?the?joint?and?range?of?motion?(ROM)?(deg)?for?? fore?and?hindlimbs?at?the?left?lead?collected?lope:?right?hind?(RH),?? left?hind?(LH),?right?fore?(RF),?and?left?fore?(LF)..........................................116?? ? 4.19??? Means?(??s.d.)?for?stance?durations?(s)?for?the?following?limbs?of?? each?stock?breed?western?pleasure?horse?(Subject?1?6)?at?the?? right?lead?extended?lope:?right?hind?(RH)?and?left?hind?(LH)....................123? ? ? ? ? xiii Table? Page? ? ?4.20? Means?(??s.d.)?for?swing?durations?(s)?for?the?following?limbs?of?? each?stock?breed?western?pleasure?horse?(Subject?1?6)?at?the?right?? lead?extended?lope:?right?hind?(RH),?left?hind?(LH),?right?fore?(RF),?? and?left?fore?(LF)................................................................................................124? ? 4.21? Means?(??s.d.)?for?left?and?right?lateral?and?diagonal?advanced?? placements?and?lift?offs?(s)?for?stock?breed?western?pleasure?horses?? at?the?right?lead?extended?lope:??left?lateral?=?LF?LH,?right?lateral?=?? RF?RH,?left?diagonal?=?RF?LH,?and?right?diagonal?=?LF?RH......................124? ? 4.22? Means?(??s.d.)?for?limb?support?phases?as?a?percent?(%)?of?stride?for?? stock?breed?western?pleasure?horses?at?the?right?lead?extended?lope.......126? ? 4.23??? Means?(??s.d.)?for?peak?flexion?and?extension?joint?angles?(deg)?measured?? on?the?flexor?side?of?the?joint?and?range?of?motion?(ROM)?(deg)?for?? fore?and?hindlimbs?at?the?right?lead?extended?lope:?right?hind?(RH),?? left?hind?(LH),?right?fore?(RF),?and?left?fore?(LF)..........................................128? 4.24??? Means?(??s.d.)?for?stance?durations?(s)?for?the?following?limbs?of?? each?stock?breed?western?pleasure?horse?(Subject?1?6)?at?the?left?? lead?extended?lope:?right?hind?(RH)?and?left?hind?(LH).............................135? ? 4.25??? Means?(??s.d.)?for?swing?durations?(s)?for?the?following?limbs?of?? each?stock?breed?western?pleasure?horse?(Subject?1?6)?at?the?left?lead?? extended?lope:?right?hind?(RH),?left?hind?(LH),?right?fore?(RF),?and?? left?fore?(LF) .......................................................................................................136? ? 4.26 Means?(??s.d.)?for?left?and?right?lateral?and?diagonal?advanced?? placements?and?lift?offs?(s)?for?stock?breed?western?pleasure?horses?? at?the?left?lead?extended?lope:??left?lateral?=?LF?LH,?right?lateral?=?? RF?RH,?left?diagonal?=?RF?LH,?and?right?diagonal?=?LF?RH......................136? ? 4.27? Means?(??s.d.)?for?limb?support?phases?as?a?percent?(%)?of?stride?? for?stock?breed?western?pleasure?horses?at?the?left?lead?extended?lope? ..138? ? ? ? xiv Table?? Page? ? 4.28??Means?(??s.d.)?for?peak?flexion?and?extension?joint?angles?(deg)?measured?? on?the?flexor?side?of?the?joint?and?range?of?motion?(ROM)?(deg)?for?fore?? and?hindlimbs?at?the?left?lead?extended?lope:?right?hind?(RH),?left?hind?? LH),?right?fore?(RF),?and?left?fore?(LF) ...........................................................140? ? 4.29?????Statistically?significant?(P?0.05)?means?(??s.d.)?for?stride?length?? (m),?velocity?(m/s),?vertical?excursion?of?the?withers?(m),?diagonal?? advanced?placement?of?the?right?fore?to?left?hind?(s),?and?limb?? support?phases?of?tripedal?with?two?forelimbs,?diagonal?bipedal,?? and?unipedal?fore?for?stock?breed?western?pleasure?horses?at?the?? right?lead?collected?and?extended?lope?(LH???left?hind,?LF???left?fore,?? RH???right?hind,?RF???right?fore).....................................................................148? ? 4.30? Statistically?significant?(P?0.05)?means?(??s.d.)?for?stride?length?(m),?? velocity?(m/s),?stride?duration?(s),?diagonal?advanced?lift?offs?(s),?? lateral?advanced?lift?off?(s),?and?unipedal?fore?limb?support?for?stock?? breed?western?pleasure?horses?at?the?left?lead?collected?and?extended?? lope?(LH???left?hind,?LF???left?fore,?RH???right?hind,?RF???right?fore)........150? ? 4.31?????Statistically?significant?(P?0.05)?means?(??s.d.)?for?angular?variables?? (deg)?of?peak?flexion,?peak?extension,?and?range?of?motion?(ROM)?for?? stock?breed?western?pleasure?horses?at?the?collected?and?extended?left?? lead?lope.............................................................................................................152? ? 5.1????? Means?(??s.d.)?for?temporal?and?linear?variables?of?the?collected?and?? extended?jog?for?the?present?study?and?the?jog?from?the?Nicodemus?? and?Clayton?(2001a)?as?well?as?the?Nicodemus?and?Booker?study?(2007).??? NP?indicates?temporal?or?linear?variables?that?were?not?present?in?? the?Nicodemus?and?Clayton?(2001a)?study...................................................161 ? ? ? ? ? ? ? ? xv Table?? Page? ? 5.2?? Means?(??s.d.)?for?temporal?and?linear?variables?of?the?collected?and?? extended?lope?for?the?present?study?and?the?lope?from?the?Nicodemus?? and?Clayton?(2001a)?as?well?as?the?Nicodemus?and?Booker?study?(2007).??? NP?indicates?temporal?or?linear?variables?that?were?not?present?in?the?? Nicodemus?and?Clayton?(2001a)?study.??Collected?and?extended?lope?? variables?linear?variables?are?as?calculated?from?right?hind?down?? placements.??Tripedal?with?two?forelimbs?and?tripedal?with?two?? hindlimbs?support?phases?as?well?as?diagonal?bipedal?limb?support?? phases?have?been?combined?for?the?sake?of?comparison............................171? 5.3? Means?(??s.d.)?for?diagonal?advanced?placement?and?diagonal?? advanced?lift?off?(s)?of?the?collected?and?extended?lope?for?the?? present?study?and?the?lope?from?the?Nicodemus?and?Clayton?(2001a)?? as?well?as?the?Nicodemus?and?Booker?study?(2007).??NP?indicates?? temporal?or?linear?variables?that?were?not?present?.....................................173? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? xvi List?of?Figures? ? ? Figure? ???Page? 1.1??Footfall?sequence?of?the?jog.??Suspension?between?each?ground?? contact?is?implied?by?the?breed?association?definition.??Each?? circle?is?representative?of?a?horse?s?hoof?(LH???left?hind,?LF???left?fore,?? RH???right?hind,?RF???right?fore).??Filled?circles?represent?stance?phase?? while?open?circles?represent?swing?phase?........................................................4? ? 1.2? Footfall?sequence?of?the?right?lead?lope.??Suspension?following?the?? third?beat?is?implied?by?the?breed?association?definition.??Each?? circle?is?representative?of?a?horse?s?hoof?(LH???left?hind,?LF???left?fore,?? RH???right?hind,?RF???right?fore).??Filled?circles?represent?stance?phase?? while?open?circles?represent?swing?phase.........................................................5? ? 1.3? Proper?headset?for?a?stock?breed?western?pleasure?horse.??The?? vertical?line?depicts?proper?head?carriage?about?the?long?axis?while?the?? horizontal?line?indicates?proper?head?and?neck?carriage?(APHA?2009).......5? ? 1.4? External?anatomy?of?the?equine?(AQHA?2002).................................................7? 1.5????? Limb?support?phases?of?the?stock?breed?western?pleasure?jog.??Each?? circle?is?representative?of?a?horse?s?hoof?(LH???left?hind,?LF???left?? fore,?RH???right?hind,?RF???right?fore).??Filled?circles?represent?stance?? phase?while?open?circles?represent?swing?phase?(Nicodemus?and?? Booker?2007).........................................................................................................10? ? 1.6? Limb?support?phases?of?the?stock?breed?western?pleasure?left? lead?lope.??Each?circle?is?representative?of?a?horse?s?hoof?(LH???left?? hind,?LF???left?fore,?RH???right?hind,?RF???right?fore).??Filled?? circles?represent?stance?phase?while?open?circles?represent?swing?? phase?(Nicodemus?and?Booker?2007)...............................................................11? ? xvii Figure? ???Page? ? 1.7? Footfall?sequence?of?the?walk.??Each?circle?is?representative?of?a?? horse?s?hoof?(LH???left?hind,?LF???left?fore,?RH???right?hind,?RF???? right?fore).??Filled?circles?represent?stance?phase?while?open?circles?? represent?swing?phase........................................................................................12? ? 1.8? Footfall?sequence?of?the?trot?with?suspension?between?each?? ground?contact.??Each?circle?is?representative?of?a?horse?s?hoof?(LH???? left?hind,?LF???left?fore,?RH???right?hind,?RF???right?fore).??Filled?circles?? represent?stance?phase?while?open?circles?represent?swing?phase..............12? ? 1.9????? Footfall?sequence?of?the?right?lead?canter?with?suspension?following?? the?third?beat.??Each?circle?is?representative?of?a?horse?s?hoof?(LH???left? hind,?LF???left?fore,?RH???right?hind,?RF???right?fore).??Filled?circles? represent?stance?phase?while?open?circles?represent?swing?phase?.............13? ? 1.10??? Footfall?sequence?of?the?left?lead?canter?with?suspension?following?? the?third?beat.??Each?circle?is?representative?of?a?horse?s?hoof?(LH???? left?hind,?LF???left?fore,?RH???right?hind,?RF???right?fore).??Filled?circles?? represent?stance?phase?while?open?circles?represent?swing?phase..............13? ? 1.11? Representation?of?what?is?seen?by?observers?during?the?stock?? breed?western?pleasure?jog.??Each?circle?is?representative?of?a?horse?s?? hoof?(LH???left?hind,?LF???left?fore,?RH???right?hind,?RF???right?fore).??? Filled?circles?represent?stance?phase?while?open?circles?represent?swing?? phase.....................................................................................................................19 1.12?????Representation?of?what?observers?see?during?the?stock?? breed?western?pleasure?lope.??Each?circle?is representative?of?a?horse?s hoof?(LH???left?hind,?LF???left?fore,?RH???right?hind,?RF???right?fore).??? Filled?circles?represent?stance?phase while open circles represent?swing?? phase.....................................................................................................................21? ? 2.1????? The?graph?in?which?nearly?all?symmetrical?gaits?of?horses?fall?? (Hildebrand?1965).??The?blue?filled?circle?indicates?the?Quarter?Horse?? while?the?orange?filled?square?indicates?the?Arabian?horse.??The?black?? filled?triangle?indicates?the?position?where?the?stock?breed?western? pleasure?jog?would?fit?into?the?continuum?.....................................................31? xviii Figure? ???Page? 2.2? The?relationship?between?symmetrical?gaits?of?horses.??Gaits?that?? would?fall?within?areas?indicated?by?dotted?lines?are?unusual?and?? have?no?common?name?(Hildebrand?1965).??The?blue?filled?circle?? indicates?the?Quarter?Horse?while?the?orange?filled?square?indicates?? the?Arabian?horse.??The?black?filled?triangle?indicates?the?position?? where?the?stock?breed?western?pleasure?jog?would?fit?into?the?? continuum............................................................................................................32? ? 3.1? Retroreflective?marker?locations?for?data?collection.??Marker?? placement?was?the?same?for?each?side?of?the?horse? ......................................69? ? 3.2? Horse?1?during?data?collection?demonstrating?placement?of?the?? reflective?markers?on?the?lateral?side?fore?and?hindlimbs,?along?the?? vertebral?column,?and?at?the?zygomatic?process.??Flat?retroreflective?? markers?were?comprised?of?polyken?(Tyco?Adhesives,?Norwood?MA)?? and?Johnson?&?Johnson?Athletic?tape?(Johnson?&?Johnson?Services,?? New?Brunswick,?NJ)...........................................................................................70? ? 3.3? Three?dimensional?markers?comprised?of?one?half?of?a?? styrofoam?ball?covered?with?Scotchlite?8850?retroreflective?tape?(Motion?? Lab?Systems,?Inc.,?Baton?Rouge,?LA)?and?mounted?on?black?foam?were?? used?along?the?vertebral?column?at?the?withers,?lumbar?sacral?junction,?? and?point?of?the?croup........................................................................................70? ? 3.4? Depiction?of?the?capture?volume?with?orange?cones?set?at?a?3.05?m?x?? 3.35?m?rectangle,?and?cameras?set?7.16?m?from?the?edge?of?the?capture?? volume?for?data?collection?of?the?collected?and?extended?jog?and?lope?? of?stock?breed?western?pleasure?horses.??Center?arrow?indicates?? direction?of?travel;?drawing?is?not?to?scale......................................................72? ? 3.5? Depiction?of?forelimb?joint?angles?for?calculation?of?joint?kinematics?? of?the?stock?breed?western?pleasure?horse:??the?proximal?end?of?the?? spine?of?the?scapula,?shoulder?joint,?elbow?joint,?carpal?joint,?forelimb?? fetlock?joint,?forelimb?coffin?joint,?and?lateral?fore?hoof................................75 ? ? ? xix Figure? ???Page? ? 3.6????? Depiction?of?hindlimb?joint?angles?for?calculation?of?joint?kinematics?? of?the?stock?breed?western?pleasure?horse:??point?of?the?hip,?hip?joint,?stifle?? joint,?hock?joint,?hindlimb?fetlock?joint,?hindlimb?coffin?joint,?and?lateral?? hind?hoof..............................................................................................................75? 4.1 ??? Lateral?footfall?sequence?of?the?collected?jog?as?performed?by?the?? stock?breed?western?pleasure?horse.??Each?circle?is?representative?of?? a?horse?s?hoof?(LH???left?hind,?LF???left?fore,?RH???right?hind,?RF???? right?fore)..............................................................................................................81? ? 4.2????? Limb?support?phases?of?the?stock?breed?western?pleasure?collected?? jog.??Each?circle?is?representative?of?a?horse?s?hoof?(LH???left?hind,?LF???? left?fore,?RH???right?hind,?RF???right?fore).??Filled?circles?represent?stance?? phase?while?open?circles?represent?swing?phase?...........................................83? ? 4.3? Representative?forelimb?motion?graph?of?the?shoulder,?elbow,?carpus,?? and?fetlock?joints?(deg)?as?a?percentage?of?stride?(%)?for?one?stride?of?? the?collected?jog?of?the?stock?breed?western?pleasure?horse.??The?gait?? cycle?was?right?hind?hoof?contact?to?the?next?contact?of?the?right?hind?? hoof,?and?the?black?vertical?line?indicates?the?initiation?of?stance?? phase.....................................................................................................................86? ? 4.4? Representative?hindlimb?motion?graph?of?the?hip,?stifle,?hock,?? and?fetlock?joints?(deg)?as?a?percentage?of?stride?(%)?for?one?stride?? of?the?collected?jog?of?the?stock?breed?western?pleasure?horse.??The?? gait?cycle?was?right?hind?hoof?contact?to?the?next?contact?of?the?right?? hind?hoof,?and?the?black?vertical?line?indicates?the?initiation?of?swing? phase.....................................................................................................................87? ? ?4.5? Representative?forelimb?motion?graph?of?the?shoulder,?elbow,?? carpus,?and?fetlock?joints?(deg)?as?a?percentage?of?stride?(%)?for?one?? stride?of?the?extended?jog?of?the?stock?breed?western?pleasure?horse.??? The?gait?cycle?was?right?hind?hoof?contact?to?the?next?contact?of?the?? right?hind?hoof,?and?the?black?vertical?line?indicates?the?initiation?of?? stance?phase.........................................................................................................92? ? ? ? xx Figure? ???Page? ? 4.6? Representative?hindlimb?motion?graph?of?the?hip,?stifle,?hock,?and?? fetlock?joints?(deg)?as?a?percentage?of?stride?(%)?for?one?stride?of?the?? extended?jog?of?the?stock?breed?western?pleasure?horse.??The?gait?cycle?? was?right?hind?hoof?contact?to?the?next?contact?of?the?right?hind?hoof,?? and?the?black?vertical?line?indicates?the?initiation?of?stance?phase?.............93? ? 4.7? Diagonal?footfall?sequence?of?the?right?lead?collected?lope?as?? performed?by?the?stock?breed?western?pleasure?horse.??Each?? circle?is?representative?of?a?horse?s?hoof?(LH???left?hind,?LF???left?fore,?? RH???right?hind,?RF???right?fore).......................................................................98? ? 4.8? Limb?support?phases?of?the?right?lead?collected?lope?as?performed?? by?the?stock?breed?western?pleasure?horse.??Each?circle?is?representative?? of?a?horse?s?hoof?(LH???left?hind,?LF???left?fore,?RH???right?hind,?RF??? right?fore)?...........................................................................................................102? ?4.9? Representative?leading?forelimb?(right?fore)?motion?graph?of?the?? shoulder,?elbow,?carpus,?and?fetlock?joints?(deg)?as?a?percentage?of?? stride?(%)?for?one?stride?of?the?right?lead?collected?lope?of?the?stock?? breed?western?pleasure?horse.??The?gait?cycle?was?right?fore?hoof?contact? to?the?next?contact?of?the?right?fore?hoof,?and?the?black?vertical?line? indicates?the?initiation?of?swing?phase? .........................................................106? ? 4.10??? Representative?trailing?forelimb?(left?fore)?motion?graph?of?the?? shoulder,?elbow,?carpus,?and?fetlock?joints?(deg)?as?a?percentage?of?stride?? (%)?for?one?stride?of?the?right?lead?collected?lope?of?the?stock?breed?? western?pleasure?horse.??The?gait?cycle?was?left?fore?hoof?contact?to?the?? next?contact?of?the?left?fore?hoof,?and?the?black?vertical?line?indicates?the?? initiation?of?swing?phase..................................................................................107?? ? 4.11??? Representative?leading?hindlimb?(right?hind)?motion?graph?of?the?? hip,?stifle,?hock,?and?fetlock?joints?(deg)?as?a?percentage?of?stride?(%)?? for?one?stride?of?the?right?lead?collected?lope?of?the?stock?breed?western?? pleasure?horse.??The?gait?cycle?was?right?hind?hoof?contact?to?the?next?? contact?of?the?right?hind?hoof,?and?the?black?vertical?line?indicates?the?? initiation?of?swing?phase?.................................................................................109?? ? ? xxi Figure? ???Page? ? 4.12??? Representative?trailing?hindlimb?(left?hind)?motion?graph?of?the?? hip,?stifle,?hock,?and?fetlock?joints?(deg)?as?a?percentage?of?stride?(%)?? for?one?stride?of?the?right?lead?collected?lope?of?the?stock?breed?western?? pleasure?horse.??The?gait?cycle?was?left?hind?hoof?contact?to?the?next?? contact?of?the?left?hind?hoof,?and?the?black?vertical?line?indicates?the?? initiation?of?swing?phase..................................................................................110 ? 4.13??? Lateral?footfall?sequence?of?the?left?lead?collected?lope?as?performed?? by?the?stock?breed?western?pleasure?horse.??Each?circle?is?representative?? of?a?horse?s?hoof?(LH???left?hind,?LF???left?fore,?RH???right?hind,?RF???? right?fore)............................................................................................................111? ? 4.14??? Limb?support?phases?of?the?left?lead?collected?lope?as?performed?by?? the?stock?breed?western?pleasure?horse.??Each?circle?is?representative?of?a?? horse?s?hoof?(LH???left?hind,?LF???left?fore,?RH???right?hind,?RF???? right?fore)............................................................................................................114? ? 4.15? Representative?leading?forelimb?(left?fore)?motion?graph?of?the?? shoulder,?elbow,?carpus,?and?fetlock?joints?(deg)?as?a?percentage?of?stride?? (%)?for?one?stride?of?the?left?lead?collected?lope?of?the?stock?breed?? western?pleasure?horse.??The?gait?cycle?was?left?fore?hoof?contact?to?? the?next?contact?of?the?left?fore?hoof,?and?the?black?vertical?line?? indicates?the?initiation?of?swing?phase ..........................................................118? ? 4.16? Representative?trailing?forelimb?(right?fore)?motion?graph?of?the?? shoulder,?elbow,?carpus,?and?fetlock?joints?(deg)?as?a?percentage?of?stride?? (%)?for?one?stride?of?the?left?lead?collected?lope?of?the?stock?breed?? western?pleasure?horse.??The?gait?cycle?was?right?fore?hoof?contact?to?? the?next?contact?of?the?right?fore?hoof,?and?the?black?vertical?line?? indicates?the?initiation?of?swing?phase ..........................................................119? ? 4.17? Representative?leading?hindlimb?(left?hind)?motion?graph?of?the?? hip,?stifle,?hock,?and?fetlock?joints?(deg)?as?a?percentage?of?stride?(%)? for?one?stride?of?the?left?lead?collected?lope?of?the?stock?breed?western?? pleasure?horse.??The?gait?cycle?was?left?hind?hoof?contact?to?the?next?? contact?of?the?left?hind?hoof,?and?the?black?vertical?line?indicates?the?? initiation?of?swing?phase?.................................................................................120? ? xxii Figure???? ?Page? ? 4.18? Representative?trailing?hindlimb?(right?hind)?motion?graph?of?the?? hip,?stifle,?hock,?and?fetlock?joints?(deg)?as?a?percentage?of?stride?(%)?? for?one?stride?of?the?left?lead?collected?lope?of?the?stock?breed?western?? pleasure?horse.??The?gait?cycle?was?right?hind?hoof?contact?to?the?next?? contact?of?the?right?hind?hoof,?and?the?black?vertical?line?indicates?the?? initiation?of?swing?phase..................................................................................121? ? 4.19? Lateral?footfall?sequence?of?the?right?lead?extended?lope?as?? performed?by?the?stock?breed?western?pleasure?horse.??Each?? circle?is?representative?of?a?horse?s?hoof?(LH???left?hind,?LF???left?fore,?? RH???right?hind,?RF???right?fore)?....................................................................122? ? 4.20? Limb?support?phases?of?the?right?lead?extended?lope?as?? performed?by?the?stock?breed?western?pleasure?horse.??Each?? circle?is?representative?of?a?horse?s?hoof?(LH???left?hind,?LF???left?fore,?? RH???right?hind,?RF???right?fore).....................................................................126?? ? 4.21? Representative?leading?forelimb?(right?fore)?motion?graph?of?the?? shoulder,?elbow,?carpus,?and?fetlock?joints?(deg)?as?a?percentage?of?stride?? (%)?for?one?stride?of?the?right?lead?extended?lope?of?the?stock?breed?? western?pleasure?horse.??The?gait?cycle?was?right?fore?hoof?contact?? to?the?next?contact?of?the?right?fore?hoof,?and?the?black?vertical?line?? indicates?the?initiation?of?swing?phase ..........................................................130? ? 4.22? Representative?trailing?forelimb?(left?fore)?motion?graph?of?the?? shoulder,?elbow,?carpus,?and?fetlock?joints?(deg)?as?a?percentage?of?stride?? (%)?for?one?stride?of?the?right?lead?extended?lope?of?the?stock?breed?? western?pleasure?horse.??The?gait?cycle?left?fore?hoof?contact?to?the?next?? contact?of?the?left?fore?hoof,?and?the?black?vertical?line?indicates?the?? initiation?of?swing?phase..................................................................................131 ? 4.23? Representative?leading?hindlimb?(right?hind)?motion?graph?? of?the?hip,?stifle,?hock,?and?fetlock?joints?(deg)?as?a?percentage?of?stride?? (%)?for?one?stride?of?the?right?lead?extended?lope?of?the?stock?breed?? western?pleasure?horse.??The?gait?cycle?right?hind?hoof?contact?to?the?next?? contact?of?the?right?hind?hoof,?and?the?black?vertical?line?indicates?the?? initiation?of?swing?phase..................................................................................132? ? xxiii Figure????? Page? ? 4.24? Representative?trailing?hindlimb?(left?hind)?motion?graph?of?the?? hip,?stifle,?hock,?and?fetlock?joints?(deg)?as?a?percentage?of?stride?? (%)?for?one?stride?of?the?right?lead?extended?lope?of?the?stock?breed?? western?pleasure?horse.??The?gait?cycle?was?left?hind?hoof?contact?to?? the?next?contact?of?the?left?hind?hoof,?and?the?black?vertical?line?? indicates?the?initiation?of?swing?phase? .........................................................133? ? 4.25? Lateral?footfall?sequence?of?the?left?lead?extended?lope?as?? performed?by?the?stock?breed?western?pleasure?horse.??Each?? circle?is?representative?of?a?horse?s?hoof?(LH???left?hind,?LF???left?fore,?? RH???right?hind,?RF???right?fore).....................................................................134? ? 4.26? Limb?support?phases?of?the?left?lead?extended?lope?as?performed?? by?the?stock?breed?western?pleasure?horse.??Each?circle?is?representative?? of?a?horse?s?hoof?(LH???left?hind,?LF???left?fore,?RH???right?hind,?? RF???right?fore)...................................................................................................138?? ? 4.27? Representative?leading?forelimb?(left?fore)?motion?graph?of?the?? shoulder,?elbow,?carpus,?and?fetlock?joints?(deg)?as?a?percentage?of?stride?? (%)?for?one?stride?of?the?left?lead?extended?lope?of?the?stock?breed?? western?pleasure?horse.??The?gait?cycle?was?left?fore?hoof?contact?to?? the?next?contact?of?the?left?fore?hoof,?and?the?black?vertical?line?? indicates?the?initiation?of?swing?phase ..........................................................142?? ? 4.28??? Representative?trailing?forelimb?(right?fore)?motion?graph?of?the?? shoulder,?elbow,?carpus,?and?fetlock?joints?(deg)?as?a?percentage?of?stride?? (%)?for?one?stride?of?the?left?lead?extended?lope?of?the?stock?breed?? western?pleasure?horse.??The?gait?cycle?was?right?fore?hoof?contact?to?? the?next?contact?of?the?right?fore?hoof,?and?the?black?vertical?line?indicates?? the?initiation?of?swing?phase? ..........................................................................143?? ? 4.29??? Representative?leading?hindlimb?(left?hind)?motion?graph?of?the?? hip,?stifle,?hock,?and?fetlock?joints?(deg)?as?a?percentage?of?stride?(%)?? for?one?stride?of?the?left?lead?extended?lope?of?the?stock?breed?western?? pleasure?horse.??The?gait?cycle?was?left?hind?hoof?contact?to?the?next?? contact?of?the?left?hind?hoof,?and?the?black?vertical?line?indicates?the?? initiation?of?swing?phase?.................................................................................144? ? xxiv Figure? ???Page? ? 4.30??? Representative?trailing?hindlimb?(right?hind)?motion?graph?of?the?? hip,?stifle,?hock,?and?fetlock?joints?(deg)?as?a?percentage?of?stride?(%)?? for?one?stride?of?the?left?lead?extended?lope?of?the?stock?breed?western?? pleasure?horse.??The?gait?cycle?was?right?hind?hoof?contact?to?the?next?? contact?of?the?right?hind?hoof,?and?the?black?vertical?line?indicates?the?? initiation?of?swing?phase..................................................................................145? 5.1? The?graph?in?which?nearly?all?symmetrical?gaits?of?horses?fall?? (Hildebrand?1965).??The?blue?filled?circle?indicates?the?Quarter?Horse?? while?the?orange?filled?square?indicates?the?Arabian?horse.??The?? black?filled?triangle?(partially?hidden)?indicates?the?stock?breed?western?? pleasure?jog?as?determined?by?Nicodemus?and?Booker?(2007).??The?yellow?? filled?diamond?indicates?the?position?where?the?collected?jog?would?fit?? into?the?continuum?while?the?purple?filled?oval?indicates?the?position?? where?the?extended?jog?would?fit?into?the?continuum................................156?? ? 5.2? The?relationship?between?symmetrical?gaits?of?horses.??Gaits?that?? would?fall?within?areas?indicated?by?dotted?lines?are?unusual?and?? have?no?common?name?(Hildebrand?1965).??The?blue?filled?circle?? indicates?the?Quarter?Horse?while?the?orange?filled?square?indicates?the?? Arabian?horse.??The?black?filled?triangle?(partially?hidden)?indicates?? the?stock?breed?western?pleasure?jog?as?determined?by?Nicodemus?? and?Booker?(2007).??The?yellow?filled?diamond?indicates?the?position?? where?the?collected?jog?would?fit?into?the?continuum?while?the?purple?? filled?oval?indicates?the?position?where?the?extended?jog?would?fit?? into?the?continuum............................................................................................157? ? ?5.3? Forelimb?motion?graph?of?the?shoulder,?elbow,?carpus,?and?? fetlock?joints?(deg)?as?a?percentage?of?stride?(%)?for?one?stride?of?the?? jog?of?the?stock?breed?western?pleasure?horse?(Booker?2005;?Nicodemus? and?Booker?2007).??The?black?vertical?line?indicates?hoof?off?? ...................164? ? ?5.4? Hindlimb?motion?graph?of?the?hip,?stifle,?hock,?and?fetlock?joints?? (deg)?as?a?percentage?of?stride?(%)?for?one?stride?of?the?jog?of?the?? stock?breed?western?pleasure?horse??(Booker?2005;?Nicodemus?and?? Booker?2007).??The?black?vertical?line?indicates?hoof?off?............................165? xxv ? Figure? ???Page? ? 5.5???????Mean?(solid?lines)???SD?(dashed?lines)?joint?motion?for?the?? shoulder?and?elbow?joints?of?the?leading?forelimb?during?the?? lope?of?the?stock?breed?western?pleasure?horse?(Nicodemus?and?Booker? 2007).??The?black?vertical?line?indicates?hoof?off...........................................174? ? 5.6? Mean?(solid?lines)???SD?(dashed?lines)?joint?motion?for?the?? ????????????carpus?and?forelimb?fetlock?joints?of?the?leading?forelimb?during?? ????????????the? lope? of? the? stock? breed? western? pleasure? horse? (Nicodemus? and? Booker?2007).??The?black?vertical?line?indicates?hoof?off.............................175? ? 5.7? Mean?(solid?lines)???SD?(dashed?lines)?joint?motion?for?the?hip?? and?stifle?joints?of?the?leading?hindlimb?during?the?lope?of?the?? stock?breed?western?pleasure?horse?(Nicodemus?and?Booker?2007).??? The?black?vertical?line?indicates?hoof?off.......................................................176? ? 5.8? Mean?(solid?lines)???SD?(dashed?lines)?joint?motion?for?the?? hock?and?hindlimb?fetlock?joints?of?the?leading?hindlimb?during?the?? lope?of?the?stock?breed?western?pleasure?horse?(Nicodemus?and?Booker? 2007).??The?black?vertical?line?indicates?hoof?off...........................................177? ? ? ? ? ? ? xxvi List?of?Abbreviations? ? APHA?? American?Paint?Horse?Association? ? ApHC?? Appaloosa?Horse?Club? ? AQHA? American?Quarter?Horse?Association? ? deg?? Degrees? ? LF?? Left?fore?hoof? ?? LH?? Left?hind?hoof? ? m?? Meters? ? ms?? Milliseconds? ? m/s?? Meters?per?Second? ? PBHA?? Palomino?Breeders?Horse?Association? ? RF?? Right?fore?hoof? ? RH?? Right?hind?hoof? ? ROM?? Range?of?motion? ? s?? Seconds? ? stride/s? Strides?per?Second? ? TWH?? Tennessee?Walking?Horse? ? U.S.?? United?States? 1 Chapter?1? ? Introduction? ? ? ? Stock?Breed?Horses? ? Stock? horse? breeds? were? originally? developed? to? run? short? races,? the? quarter? mile,? and? due? to? their? disposition? and? personality,? soon? became? a? favorite?of?cowboys?and?ranch?hands.??Dubbed??quarter?horses??because?of?their? speed?over?the?quarter?mile,?these?hardy?horses?with?unique?cow?sense?began?to? excel?at?ranch?work?such?as?driving?and?cutting?cattle?(Oelke?1992).??In?the?mid? 1900s? the? focus? of? horses? as?work?animals?changed?to?horses?being?promoted? more?as?animals?of?leisure?and?sport?(Back?1994).??As?the?popularity?of?equine? related? sports? increased,? breed? associations? were? developed? to? keep? track? of? pedigrees?and?performance?records.??Formation?of?the?largest?breed?registry?in? the?world,?the?American?Quarter?Horse?Association?(AQHA),?occurred?in?1940? (Oelke?1992).???Today,?stock?type?horse?breeds?make?up?the?majority?of?registered? horses?in?the?United?States?(U.S.)?and?are?registered?through?four?main?breed? associations:??American? Quarter? Horse? Association? (AQHA),? American? Paint? 2 Horse?Association?(APHA),?Palomino?Breeders?Horse?Association?(PBHA),?and? Appaloosa?Horse?Club?(ApHC).??? American?Quarter?Horse?Association?is?the?largest?stock?breed?registry?in? the? U.S.? with? 2,821,172? registered? Quarter? Horses? in? 2008.??Total? international? registrations? boast? numbers? of? 129,054? with? members? in? the? Bahamas,? Czech? Republic,?Madagascar,?and?South?Africa?(AQHA?2008).??As?the?second?largest? U.S.?breed?registry,?the?APHA?had?approximately?1,000,000?registrations?in?2008? (APHA? 2008).??International? memberships? include? countries? such? as? Canada,? Mexico,?United?Kingdom,?and?Taiwan.??With?well?over?84,955?APHA?members? in?the?United?States?and?abroad,?awareness?of?the?Paint?is?worldwide.??Originally? founded?in?California,?the?PBHA?boasts?numbers?of?over?71,000?registered?horses? and?87,000?members?(PHBA?2009).??Appaloosa?Horse?Club?horse?registrations? exceed? 630,000? with? Texas,? Minnesota,? Missouri,? California,? and? Oklahoma? leading? the? nation? in? registration? numbers? (ApHC? 2009a).??Appaloosas? have? received?international?registrations?in?countries?such?as?Canada,?Germany,?Italy,? and?Belgium.??With?representation?in?working?cattle,?dressage,?jumping,?western? performance,?english?performance,?endurance,?trail?riding,?or?track?racing,?stock? horse?breeds?excel?in?all?disciplines?and?continue?to?gain?popularity?worldwide.??? ? ? ? 3 Western?Pleasure? While? stock? type? breeds? are? ridden? in? various? disciplines,? the? class? perceived? as? the? most? prestigious? and? competitive? at? breed? shows? is? western? pleasure?(Nice?2006;?Noble?2001;?Oelke?1992).??Western?pleasure?began?as?a?way? to? showcase? ranch? horses? with? comfortable? gaits,? attractive? appearance,? and? willing?attitudes?as?well?as?to?prepare?the?horses?for?other?events?such?as?reining,? roping,?or?cutting.??However,?the?popularity?of?western?pleasure?rose?in?the?1970s? to?become?a?separate?sport?and?a?way?to?showcase?a?well?broke?horse?at?a?walk,? jog,?and?lope?(Meyer?2005).???Western?pleasure?is?judged?on?the?horse?s?ability?to? be? a? ?pleasure?? to? ride,? and? horses? are? selected? for? competition? based? on? conformational? and? locomotive? characteristics? established? by? current? breed? standards.???To?meet?these??pleasurable??standards,?stock?horses?competing?in? western?pleasure?should?be?relaxed,?broke,?quiet,?and?responsive?to?cues?while? showing? no? hesitation? (AQHA? 1994).??Stock? horses? are? evaluated? on? similar? standards?of?gait?across?breeds?with?quality?of?movement?and?consistency?of?gait? being?paramount.??Gaits?and?transitions?between?the?walk,?jog,?and?lope?should? be?smooth?and?all?gaits?should?be?a?pleasure?to?ride?(Oelke?1992).??? According?to?AQHA,?APHA,?PHBA,?and?ApHC,?the?jog?is?defined?as?a? two? beat? diagonal? gait? that? should? be? smooth,? balanced,? and? square,? with? a? straightforward?movement?of?the?legs?and?hooves?(Figure?1.1).??While?a?properly? 4 LH RFRH LF 3 RH RF LH 1 LF 2 LH LF RH RF 4 LH LF RH RF performed?lope,?as?defined?by?breed?associations,?is?an?easy,?rhythmical,?clean? three? beat? gait? (Figure? 1.2).??An? excellent? jog? and? lope? are? characterized? by? a? bright,?alert?expression?and?effortless?yet?efficient?motion?that?results?in?the?horse? touching? the? ground? softly.??The? long? axis? of? the? head? should? remain? almost? perpendicular?to?the?ground?throughout?all?gaits,?and?horses?should?be?balanced? with?a?level?topline?(Figure?1.3).??A?horse?s?poll?(nuchal?crest),?or?the?top?of?the? head?located?between?the?ears,?should?remain?level?or?slightly?above?the?withers? (highest?point?of?thoracic?vertebrae?3?or?4),?or?top?of?the?shoulders?(Figure?1.3).??? ? ? ? ? ? ? ? Figure? 1.1:??Footfall? sequence? of? the? jog.??Suspension? between? each? ground? contact? is? implied? by? the? breed? association? definition? (APHA? 2009;? ApHC? 2009b;? AQHA? 2009;? PHBA? 2008).??Each? circle? is? representative?of?a?horse?s?hoof?(LH???left?hind,?LF???left?fore,?RH???right? hind,?RF???right?fore).??Filled?circles?represent?stance?phase?while?open? circles?represent?swing?phase.??? ? ? ? ? ? ? ? 5 RH RF LH 2 LF LH LF RH RF 1 LH LF RH RF 3 4 LH LF RH RF ? ? ? ? ? Figure? 1.2:??Footfall? sequence? of? the? right? lead? lope.??Suspension? following? the? third? beat? is? implied? by? the? breed? association? definition? (APHA? 2009;? ApHC? 2009b;? AQHA? 2009;? PHBA? 2008).??Each? circle? is? representative?of?a?horse?s?hoof?(LH???left?hind,?LF???left?fore,?RH???right? hind,?RF???right?fore).??Filled?circles?represent?stance?phase?while?open? circles?represent?swing?phase.??? ? ? ? ? Figure?1.3:??Proper?headset?for?a?stock?breed?western?pleasure?horse.??The? vertical?line?depicts?proper?head?carriage?about?the?long?axis?while?the? horizontal?line?indicates?proper?head?and?neck?carriage?(APHA?2009).?? Withers Poll? 6 Excellent? jogging? and? loping? horses? are? confident,? balanced,? and? under? control.??The?knee?and?hock?joints?should?remain?flat?throughout?the?stride?with? cushion?exhibited?at?the?pastern;?horses?should?have?a?strong?deep?stride?and? never?allow?the?hocks?to?drift?into?the?tail?(Figure?1.4).??Horses?should?be?relaxed? and?lope?at?a?comfortable?speed?with?a?free?flowing,?ground?covering?stride?of? reasonable?length.??A?straight?line?from?hip?to?toe?and?a?slightly?rounded?back?is? indicative?of?collection?and?engagement?and?are?desired?in?the?arena?because?this? self?carriage? allows? the? horse? increased? reach? from? behind? while? the? stride? is? finished? through? the? shoulders? with? natural? flow.??Excellent? western? pleasure? horses? should? display? a? great? degree? of? lift? and? self?carriage,? and? each? gait? should? be? performed? at? a? speed? that? is? natural? to? the? horse?s? way? of? going? (APHA?2009;?ApHC?2009b;?AQHA?2009;?PHBA?2008).??? ? 7 ? Figure?1.4:??External?anatomy?of?the?equine?(AQHA?2002).??? ? In?the?1970s,?trainers?and?exhibitors?began?decreasing?the?speed?at?which? the?horses?moved?in?order?to?win;?public?perception?was?that?the?slowest?horse?in? the? pen? was? the? most? desirable? and? was? often? the? winner? (Nice? 2006).??The? demand?for?a?slower?moving,?more?collected?western?pleasure?horse?resulted?in? undesirable? gait? characteristics? being? performed? during? competition,? as? determined? by? the? industry? and? scientists? alike? (Barakat? 2008;? Eppers? and? Hamilton?2008;?Kuhlwein?2002;?Meyer?2005;?Nice?2006;?Nicodemus?and?Booker? 2007;?Nicodemus?and?Clayton?2001a).??For?a?horse?to?achieve?collection,?the?body? and?back?must?be?rounded?thereby?lifting?the?shoulders?so?that?the?hindquarters? reach?as?far?under?the?body?as?possible?(Hokana?and?Hamilton?2010).??Collected? 8 gaits? put? great? demand? on? conformation? and? function? of? the? hindlimbs? (Holmstr?m? et? al.? 1994),? and? as? an? industry,? stock? breed? western? pleasure? requires?high?levels?of?collection?for?horses?to?excel?in?the?show?arena.??Inability? to?attain?gait?collection?caused?stock?breed?western?pleasure?horses?to?adapt?and? move?so?slowly?that?all?suspension,?which?existence?is?implied?based?on?breed? association? gait? definitions,? has? been? lost? (APHA? 2009;? ApHC? 2009b;? AQHA? 2009;?Barakat?2008;?Kuhlwein?2002;?Rogers?2004;?Williams?2004).??Unnatural?gait? adaptations?caused?the?horse?to?appear?as?if?it?was?hopping?slowly?down?the?rail? with?downhill?momentum?as?it?pulled?itself?using?its?forelimbs.??Horses?began?to? be? overcanted? and? were? forced? to? lope? unnaturally? slow? by? pitching? the? hip? toward?the?center?of?the?ring?while?the?head?and?outside?shoulder?remained?on? the?rail.??In?2001,?Nicodemus?and?Clayton?found?that?neither?the?jog?nor?lope?had? a?phase?of?suspension?making?the?gait?a?stepping?gait?instead?of?a?leaping?gait,? with?both?gaits?having?lateral?footfalls?(Nicodemus?and?Clayton?2001a).??These? findings?were?contradictory?to?the?breed?association?definitions?for?the?jog?and? lope.? The?year?2005?was?monumental?for?stock?breed?western?pleasure?as?rule? changes?dictated?by?breed?associations?better?defined?the?jog?and?lope?in?order?to? correct? the? ultra? slow,? artificial? gaits? being? performed.??Rules? now? require? an? extension? of? the? jog? in? at? least? one? direction? of? the? arena.??By? definition,? the? 9 extended? jog? should? show? an? increase? in? speed,? be? flat,? cadenced,? and? quiet.?? Extension,?does?not,?however,?mean?an?increase?in?speed?alone;?but?rather,?the? emphasis?is?on?engagement?from?the?hindquarters?resulting?in?extension?of?the? horse?s?leg.??Further,?the?only?gait?recognizable?as?a?lope?will?have?an?increase?in? forward?motion?and?the?horse?s?hip?should?not?be?canted?toward?the?center?of? the? arena.??Research? conducted? by? Nicodemus? and? Booker? (2007)? after? rule? changes?took?effect?in?stock?breed?western?pleasure?competition?concluded?that? horses?were?still?performing?the?jog?and?lope?as?four?beat?stepping?gaits?with? lateral?footfall?sequence?and?no?period?of?suspension?(Figures?1.5?&?1.6).??The?jog? was?symmetrical?(Figure?1.5)?while?the?lope?was?an?asymmetrical?gait?with?leads? (Figure?1.6).??Both?the?jog?and?lope?were?performed?with?diagonal?couplets?as? diagonal? limb? pairs? for? each? gait? moved? closely? together? in? time? instead? of? simultaneously? (Figure? 1.5? &? 1.6).??However,? gait? improvements? and? more? detailed?guidelines?did?result?in?improvements?in?the?gait?when?compared?to?the? earlier?(Nicodemus?and?Clayton?2001a)?four?beat?jog?and?lope?study.??Stock?breed? western? pleasure? horses? performed? the? jog? with? more? diagonal? limb? support? than?did?the?horses?in?the?earlier?study.??Additionally,?the?inclusion?of??forward? motion??judging?criterion?during?the?lope?resulted?in?no?quadrupedal?support,? which?was?found?in?the?Nicodemus?and?Clayton?(2001a)?study?(Nicodemus?and? Booker?2007).??? 10 LH LF RH RF 1 LH LF RH RF 4 LH LF RH RF 2 LH LF RH RF 3 LH LF RH RF 5 LH LF RH RF 7 LH LF RH RF 8 LH LF RH RF 6 ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? Figure?1.5:?Limb?support?phases?of?the?stock?breed?western?pleasure?jog.?? Each?circle?is?representative?of?a?horse?s?hoof?(LH???left?hind,?LF???left? fore,?RH???right?hind,?RF???right?fore)?(Nicodemus?and?Booker?2007).?? Filled?circles?represent?stance?phase?while?open?circles?represent?swing? phase.??? 11 LH LF RH RF 1 LH LF RH RF 2 LH LF RH RF 3 LH LF 4 LH LF RH RF 5 LH LF RH RF 6 LH LF RH RF 7 LH LF RH RF 8 ? Figure?1.6:??Limb?support?phases?of?the?stock?breed?western?pleasure? left?lead?lope.??Each?circle?is?representative?of?a?horse?s?hoof?(LH???left? hind,?LF???left?fore,?RH???right?hind,?RF???right?fore)?(Nicodemus?and? Booker?2007).??Filled?circles?represent?stance?phase?while?open?circles? represent?swing?phase.??? ? ? Statement?of?the?Problem? Extensive? kinematic? research? on? European? horse? breeds? has? assisted? in? correctly? defining? gaits? including? the? walk,? trot,? and? canter.??As? defined? by? Barrey?(2001),?the?walk?is?a?four?beat?gait?with?no?period?of?suspension?and?an? overlap?between?the?stance?phases?of?limbs?(Figure?1.7).??The?trot?is?described?as? a? two? beat,? symmetrical,? diagonal? gait? with? suspension? that? has? variations? including?the?collected,?working,?medium,?and?extended?trots?(Figure?1.8).??The? canter?is?a?three?beat,?asymmetrical?gait?that?is?described?as?having?right?or?left? leads?and?suspension?(Figure?1.9?&?1.10)?(Barrey?2001).? RH RF 12 LH LF RH RF 1 LH LF RH RF 4 LH LF RH RF 2 LH LF RH RF 3 LH RFRH LF 3 RH RF LH 1 LF 2 LH LF RH RF 4 LH LF RH RF ? ? ? ? ?? ? ? ? ? ? ? Figure?1.7:??Footfall?sequence?of?the?walk.??Each?circle?is?representative? of?a?horse?s?hoof?(LH???left?hind,?LF???left?fore,?RH???right?hind,?RF??? right? fore).??Filled? circles? represent? stance? phase? while? open? circles? represent?swing?phase.??? ? ? ? ? ? Figure?1.8:??Footfall?sequence?of?the?trot?with?suspension?between?each? ground?contact.??Each?circle?is?representative?of?a?horse?s?hoof?(LH???left? hind,? LF? ?? left? fore,? RH? ?? right? hind,? RF? ?? right? fore).??Filled? circles? represent?stance?phase?while?open?circles?represent?swing?phase.??? ? ? ? ? ? 13 RH RF LH 2 LF LH LF RH RF 1 LH LF RH RF 3 4 LH LF RH RF RFRH RH LH RF LF 1 LH RH RF LF 3 LH LF 2 4 LH LF RH RF Figure?1.9:??Footfall?sequence?of?the?right?lead?canter?with?suspension? following?the?third?beat.??Each?circle?is?representative?of?a?horse?s?hoof? (LH???left?hind,?LF???left?fore,?RH???right?hind,?RF???right?fore).??Filled? circles?represent?stance?phase?while?open?circles?represent?swing?phase.??? ? Figure?1.10:??Footfall?sequence?of?the?left?lead?canter?with?suspension? following?the?third?beat.??Each?circle?is?representative?of?a?horse?s?hoof? (LH???left?hind,?LF???left?fore,?RH???right?hind,?RF???right?fore).??Filled? circles?represent?stance?phase?while?open?circles?represent?swing?phase.? ? Furthermore,? despite? the? scientific? definitions,? the? jog? and? lope? are? considered?to?be?adaptations?of?the?trot?and?canter,?respectively,?performed?by? the?stock?breed?western?pleasure?horse.??So,?while?the?jog?and?lope?appear?to?be? variations?of?the?trot?and?canter,?they?are?four?beat?stepping?gaits?similar?to?the? equine? walk? and? non?walking? stepping? gaits? of? gaited? horses.??In? an? effort?to? correct?these?gait??abnormalities??breed?associations?have?introduced?new?rules;? 14 however,?inconsistencies?still?exist.??The?current?project?sought?to?identify?if?the? extended?jog?and?lope?more?closely?resemble?breed?association?definitions?when? compared?to?the?collected?jog?and?lope?of?stock?breed?western?pleasure?horses,? which? incorrectly? implies? that? western? pleasure? horses? are? performing? a? variation?of?the?trot?and?canter.??Further,?it?is?accepted?that?elite?performance? horses?that?have?been?showing?at?the?national?level?since?the?age?of?two?do?not? often? maintain? a? show? career? after? the? age? of? five.??This? lack? of? senior? performance? horses? is? anecdotally? linked? to? the? intense? training? these? horses? receive? early? in? the? show? career? and? the? ultra? slow? gait? they? are? expected? to? achieve.??This?investigation?will?lead?to?insight?in?the?performance?of?these?gaits? and?may?help?determine?whether?the?high?level?of?collection?required?to?perform? the?jog?and?lope,?coupled?with?the?speed?of?the?gait,?increases?the?horse?s?risk?for? joint? injury? and? trauma.??As? this? project? will? provide? for? the? systematic? evaluation?of?these?gaits,?particular?gait?mechanics?may?be?identified?that?could? be?contributors?to?articular?joint?break?down?of?western?pleasure?horses.??? ? Purpose?of?the?Study? The? purpose? of? this? study? was? to? collect? temporal,? linear,? and? angular? kinematics?for?each?gait?in?order?to?compare?the?variables?of?the?collected?and? extended?jog?and?the?collected?and?extended?lope?to?determine?consistency?with? 15 current? rule? books? of? the? major? stock? breed? associations.??Additionally,? head? position?was?compared?to?determine?consistency?with?current?rulebooks?of?the? major?stock?breed?associations.??Comparisons?of?these?variables?answered?several? questions:??1)?Do?stock?breed?western?pleasure?horses?alter?their?stride?length? independently?of?stride?duration?for?the?collected?and?extended?jog?and?lope;?2)? Does?the?performance?of?the?extended?jog?more?closely?follow?the?guidelines?set? forth?by?major?stock?breed?associations?for?western?pleasure?competition?than? does?the?collected?jog;?3)?Does?the?performance?of?the?extended?lope?more?closely? follow? the? guidelines? set? forth? by? major? stock? breed? registries? for? western? pleasure?competition?than?does?the?collected?lope;?4)?Does?the?head?carriage?and? topline? of? the? western? pleasure? horse? during? the? extended? jog? and? lope? more? closely? follow? the? guidelines? set? forth? by? major? stock? breed? associations? for? western?pleasure?competition?than?does?the?collected?jog?and?lope;?and?5)?Does? the?performance?of?the?extended?jog?and?lope?conform?to?a?more?natural?way?of? going? for? stock? breed? western? pleasure? horses? thereby? reducing? risk? of? joint? injury?and?trauma?compared?to?the?collected?jog?and?lope???? 16 Hypotheses? Based?on?previous?research?it?was?hypothesized?that?stock?breed?western? pleasure?horses?altered?their?stride?length?independently?of?stride?duration?when? transitioning?from?the?collected?jog?and?lope?to?the?extended?jog?and?lope.??It?was? further?hypothesized?that?the?extended?jog?and?lope?more?closely?followed?the? guidelines? set? forth? by? major? stock? breed? associations? for? western? pleasure? competition? than? did? the? collected? jog? and? lope.? Horses?? head? carriage? more? closely? followed? the? guidelines? for? stock? breed? western? pleasure? during? the? extended? jog? and? lope? than? during? the? collected? jog? and? lope.??Finally,? performance?of?the?extended?jog?and?lope?conformed?to?a?more?natural?way?of? going?and?reduced?the?risk?of?joint?injury?and?trauma?than?did?the?collected?jog? and?lope.? ? Operational?Definitions? The? following? definitions? are? standard? terminology? for? equine? biomechanics? and? will? be? used? as? the? operational? definitions? for? the? current? study.? Advanced?lift?off???time?between?the?first?visible?flexion?of?the?fetlock?joint?of? two?specified?limbs?(Deuel?2001).? 17 Advanced? placement??? time? between? ground? contact? with? the? heel? of? two? specified?limbs.? Breakover???the?heel?of?the?hoof?rotates?about?the?toe,?which?is?in?contact?with?the?? ground,?in?preparation?for?swing?phase?(Clayton?2004).? Couplet???two?limbs?make?ground?contact?relatively?close?together?in?time,?not? simultaneously,?and?may?be?diagonal?or?lateral.? Diagonal?limbs???a?forelimb?and?the?contralateral?hindlimb?(Deuel?2001).???? Extension???refers? to? an? increase? in? joint? angle? and? greater? extension? of? the? horse?s? legs? rather? than? just? an? increase? in? speed.??Proper? extension? is? accomplished?through?increased?engagement?or?reach?of?the?hindquarters? underneath?the?body?of?the?horse?(APHA?2009;?ApHC?2009b;?AQHA?2009;? Deuel?2001;?PHBA?2008).? Footfall? sequence???order? in? which? the? hoofs? make? contact? with? the? ground,? always?beginning?with?the?hind?hoof.? Gait???the?cyclic,?repetitive?movement?associated?with?each?stride?distinguished?? ???????????by?the?sequence?and?timing?of?the?repetitive?movements.? Categories?of?gait:? Asymmetrical???footfalls?are?independent?from?the?opposite?side?of?the? body?including?the?canter?and?gallop?(Table?1.1).? 18 Leaping?or?running???one?or?more?suspension?phases,?where?all?limbs?are? off?the?ground,?occur?during?the?gait?including?the?trot,?canter,?and? gallop?(Table?1.1).? ? Stepping?or?walking???at?least?one?hoof?is?in?contact?with?the?ground?? throughout?the?stride?as?seen?in?the?walk.??This?gait?has?no? suspension?phase?(Table?1.1).? ? Symmetrical???actions?on?one?side?of?the?body?are?mirrored?on?the?other?? side?of?the?body?as?seen?in?the?walk?and?trot?(Table?1.1)?(Clayton? 2004).? Types?of?gaits:? Walk???four? beat,? symmetrical,? lateral? gait? with? regular? rhythm,? and? overlap?between?stance?phases?of?limbs,?but?no?suspension?(Figure? 1.7,?Table?1.1).? Trot???two?beat,?symmetrical,?diagonal?gait?with?regular?rhythm,?diagonal? pairs,? and? suspension.??The? trot? has? a? footfall? sequence? of? right? hindlimb? and? left? forelimb? followed? by? the? left? hindlimb? and? right? forelimb?moving?together?in?time?(Figure?1.8).??Suspension?phases?are? found?between?ground?contact?of?each?diagonal?pair?(Table?1.1).? ? ? 19 LH LF RH RF 1 LH LF RH RF 2 LH LF RH RF 4 LH LF RH RF 3 Jog?? Breed?Association???two?beat?gait?that?is?smooth?and?ground?covering.?? Horses?performing?the?jog?should?move?from?one?diagonal?pair?to? the? other.??Suspension? is? implied? in? this? definition? (Figure? 1.1)? (APHA?2009;?ApHC?2009b;?AQHA?2009;?PHBA?2008).??The?equine? industry?considers?the?jog?to?be?a?variation?of?the?trot.? Scientific???four?beat? stepping? gait? with? symmetry,? lateral? footfall? sequence,? irregular? rhythm,? diagonal? couplets? and? no? period? of? suspension?(Figure?1.5).? Visual? ?? observers? see? horses? making? ground? contact? with? one? diagonal?couplet?as?the?other?diagonal?couplet?is?reaching?toe?off.?? No?suspension?phase?is?visible?(Figure?1.11).? ? ? ? ? ? ? ? ? ? Figure?1.11:??Representation?of?what?is?seen?by?observers?during? the? stock? breed? western? pleasure? jog.??Each? circle? is? representative?of?a?horse?s?hoof?(LH???left?hind,?LF???left?fore,?RH? ??right?hind,?RF???right?fore).??Filled?circles?represent?stance?phase? while?open?circles?represent?swing?phase.??? 20 Canter? ??three?beat,?asymmetrical?gait?with?regular?rhythm,?suspension,? and? leads.??The? canter? has? a? footfall? sequence? of? trailing? hindlimb,? diagonal?pair,?and?leading?forelimb.??The?leading?forelimb?dictates?the? lead;?the?right?lead?has?a?footfall?sequence?of?left?hind,?right?hind?and? left?fore,?right?forelimb?(Figure?1.10)?while?the?left?lead?has?a?footfall? sequence? of? right? hind,? left? hind? and? right? fore,? and,? left? forelimb? (Figure? 1.9).??The? suspension? phase? follows? beat? three? (Table? 1.1)? (Deuel?2001).?? ? ? Lope? ? Breed?Association???easy,?rhythmical,?clean?three?beat?gait.??Suspension? is?implied?in?this?definition.??Horses?loping?to?the?left?should?be?on? the?left?lead?while?horses?loping?to?the?right?should?be?on?the?right? lead?(Figure?1.2)?(APHA?2009;?ApHC?2009b;?AQHA?2009;?PHBA? 2008).??The?equine?industry?considers?the?lope?to?be?a?variation?of? the?canter.? Scientific???four?beat? stepping? gait? with? asymmetry,? lateral? footfall? sequence? and? irregular? rhythm.??The? lope? has? leads? with? the? footfalls?beginning?with?the?trailing?hind,?followed?by?the?leading? hind?and?trailing?fore?working?as?a?diagonal?couplet,?and?finally? the?leading?forelimb?(Figure?1.6)?(Nicodemus?and?Booker?2007).? 21 RH RFRFRH RH LH RF LF 1 LH LF 3 LH LF 2 Visual???horses?appear?to?be?making?ground?contact?with?the?leading? forelimb? as? the? trailing? hindlimb? is? entering? swing? phase.??No? suspension?is?visible?during?the?lope?(Figure?1.12).? ? ? ? ? ? ? ? ? ? Figure? 1.12:??Representation? of? what? observers? see? during?the?stock?breed?western?pleasure?left?lead?lope.?? Each?circle?is?representative?of?a?horse?s?hoof?(LH???left? hind,?LF???left?fore,?RH???right?hind,?RF???right?fore).?? Filled?circles?represent?stance?phase?while?open?circles? represent?swing?phase.??? ? 22 Table?1.1:??Scientific?classification?of?equine?gaits???right?hind?(RH),?right?fore? (RF),?left?hind?(LH),?and?left?fore?(LF)?(Barrey?2001).??? Classification? Gait? Gait? Variations? Footfall? Sequence? Beats/stride? Symmetry Walk? Collected? Medium? Extended? RH,?RF,?? LH,?LF? 4? Yes? Toelt? Paso? Rack? Fox?trot? Medium? RH,?RF,?? LH,?LF? 4? Yes? Jog? Collected? Extended? RH?LF,?? LH?RF? 2? Yes? Stepping?? Gaits? Lope? Collected?? Extended? Trailing?H,?? Leading?H?&? Trailing?F,?? Leading?F? 3? No? Trot? Piaffe? Passage? Collected? Medium? Extended? Flying?trot? RH?LF,? Suspension,?? LH?FR,? Suspension? 2? Yes? Pace? Medium? Extended? RH?RF,? Suspension? LH?LF,? Suspension? 2? Yes? Canter? Collected? Medium? Extended? Disunited? Trailing?H,?? Leading?H?&? Trailing?F,?? Leading?F,? Suspension? 3? No? Leaping?? Gaits? Gallop? Transverse? Rotary? Transverse:?? Trailing?H,?? Leading?H,? Trailing?F,? Leading?F,? Suspension? 4? No? ? ? ? 23 Types?of?horses:? Gaited???horses?that?perform?gaits?in?addition?to?or?instead?of?the?natural? walk,?trot,?and?canter.??These?horses?are?classified?as?three?gaited?or? five?gaited?and?perform?gaits?such?as?the?flat?walk,?running?walk,? rack,?stepping?pace,?amble,?toelt,?paso?largo,?and?paso?corto.??Some? breeds?of?horses?that?are?classified?as?gaited?include?the?American? Saddlebred,? Missouri? Fox? Trotter,? Icelandic,? Tennessee? Walking? Horse,?Paso?Fino,?and?Peruvian?Paso?(Thomas?2005).??? Non?gaited???horses?that?perform?natural?gaits?known?as?the?walk,?trot,? and?canter?(Thomas?2005).??? Joint?Nomenclature:?for?the?purpose?of?the?current?study?the?following?common? joint?names?were?substituted?for?anatomical?joint?names?for?simplicity?and? clarity?(Table?1.2)?(Kainer?and?McCracken?1998).? ?? 24 Table?1.2:??Anatomical?and?common?joint?names?for?all?? joints?analyzed?in?the?current?study?(Kainer?and?? McCracken?1998).??Common?joint?names?will?be?used?in?? order?to?promote?simplicity?and?clarity.? Anatomical?Joint?Names? Common?Joint?Names? Antebrachiocarpal? Midcarpal? Carpometacarpal? Intercarpal? Carpal/Carpus? Coxofemoral? Hip? Cubital? Elbow? Femoropatellar? Femorotibial? Stifle? Humeral? Shoulder? Metacarpophalangeal? Fetlock? Proximal?Interphalangeal? Pastern? Proximal?Intertarsal? Distal?Intertarsal? Tarsometatarsal? Tarsocrural? Hock? ? ? Lateral?limbs???ipsilateral?fore?and?hindlimbs?(Deuel?2001).? ? Leading?limb???the?second?of?two?hindlimbs?or?two?forelimbs?to?touch?and?leave?? the?ground?during?an?asymmetrical?gait.? Limb?support?sequence???sequence?of?limb?combinations?that?support?the?body? during?stance?phase?(Clayton?2004).? Bipedal?or?double?limb?support???two?limbs?support?the?body?and?may? consist?of?diagonal?or?lateral?limbs?or?fore?or?hindlimbs.? ? Quadrupedal?limb?support???all?four?limbs?support?the?body? 25 Tripedal? limb? support? ?? three? limbs? support? the? body? and? may? be? comprised? of? two? forelimbs? and? one? hindlimb? or? two? hindlimbs? and?one?forelimb.? Unipedal?limb?support???one?limb?is?in?stance?phase.? Overlap??? during? one? or? more? stride? phases? two? limbs? are? simultaneously? in? stance?(Deuel?2001).? Overstride???the?hind?hoof?steps?over?the?track?of?the?front?hoof?as?it?leaves?the? ground?(Clayton?2004).? Suspension???period?during?the?gait?cycle?when?all?limbs?are?off?the?ground? Trailing?limb???the?first?of?two?hindlimbs?or?two?forelimbs?to?touch?and?leave?the? ground?during?an?asymmetrical?gait?(Deuel?2001).? 26 Chapter?II? ? ? Literature?Review? ? ? ? The? purpose? of? this? study? was? to? collect? temporal,? linear,? and? angular? kinematics?for?each?gait?of?the?stock?breed?western?pleasure?horse?in?order?to? compare?the?variables?of?the?collected?and?extended?jog?and?the?collected?and? extended? lope? as? well? as? head? position? to? determine? consistency? with? current? rulebooks?of?major?stock?breed?associations.??Additionally,?this?study?sought?to? determine?if?the?extended?jog?and?lope?conform?to?a?less?restrictive?movement? pattern?for?stock?breed?western?pleasure?horses,?which?may?reduce?the?risk?of? joint?injury?and?trauma?than?does?the?collected?jog?and?lope.??The?current?chapter? presents? the? review? of? literature? on? the? topics? of? a)? defining? gaits? through? kinematics,?b)?head?carriage,?and?c)?injuries.? Equine? biomechanics? research? after? 1965? has? shown? that? Hildebrand? (1965)?was?correct?when?he?stated?that?a?horse?s??locomotion?is?more?controllable? 27 than?that?of?other?animals,?and?at?the?hand?of?man?it?has?learned?to?be?versatile?in? the?selection?of?gaits?and?also?to?use?gaits?.?.?.?that?are?unnatural?to?the?species?and?? unique?to?itself.????Modern?computerized?gait?analysis?equipment,?when?used?to? quantify? locomotor? performance,? improves? objectiveness? and? correctness? of? selection? and? assessment? when? evaluating? stock? breed? western? pleasure? prospects?and?has?allowed?researchers?to?define?various?gaits?and?the?variables? that? influence? these? gaits.??The? human? eye,? even? if? trained,? is? not? able? to? see? subtle?differences?in?conformation?or?gait?adaptations?as?precisely?as?computer? analysis.??Therefore,?as?the?competitive?nature?of?horse?showing?increases,?it?is? pertinent? that? accurate? and? objective? techniques? are? used? to? measure? conformation?and?locomotion?in?order?to?provide?scientific?data?to?be?used?for? defining? and? classifying? gaits? as? well? as? for? clinical? and? performance? applications.??? Defining?Gaits?Through?Kinematics? Gait?is?a?term?that?is?used?to?encompass?the?cyclic?movements?associated? with?each?stride,?and?it?is?the?sequence?and?timing?of?the?repetitive?movements? that?help?distinguish?specific?gait?patterns?(Nicodemus?and?Clayton?2003)?and?for? the? remainder? of? this? project? will? refer? to? the? gait? of? horses.??Gait? may? be? classified?into?several?categories:??(a)?symmetrical?or?asymmetrical,?(b)?diagonal? 28 or? lateral? footfall? sequences,? and? (c)? stepping? or? leaping? (Grogan? 1951).?? Symmetrical?gaits?such?as?the?walk,?flat?walk,?classic?fino,?trot,?pace,?stepping? pace,?and?fox?trot?are?classified?as?such?due?to?the?mirrored?actions?occurring?on? the? opposite? side? of? the? body? (Barrey? 1999;? Clayton? and? Bradbury? 1995;? Hildebrand?1965;?Nicodemus?and?Clayton?2001b;?Nicodemus?and?Holt?2003a).?? Gaits?with?footfalls?moving?independently?from?the?opposite?side?of?the?body?are? classified?as?asymmetrical?and?include?the?canter?and?gallop.??Footfall?sequence?is? determined? independently? from? symmetry;? however,? both? symmetrical? and? asymmetrical?gaits?may?exhibit?a?diagonal?or?lateral?footfall?sequence.??Diagonal? footfall? is? attained? when? forelimb? hoof? contact? is? in? sequence? with? the? hoof? contact? of? the?diagonal?hindlimb,?as?with?the?trot.??Thus,?forelimb?and?lateral? hindlimb?synchronization?classify?a?lateral?gait?as?exhibited?in?the?walk?and?pace.?? Gaits? are? also? categorized? by? whether? a? flight? phase? exists? during? the? stride.?? Stepping?gaits,?such?as?the?walk,?are?characterized?by?at?least?one?limb?being?in? contact?with?the?ground?throughout?the?stride,?and?leaping?gaits,?such?as?the?trot? and?canter,?have?a?period?of?suspension?(Grogan?1951).??Suspension,?or?the?flight? phase,?is?a?period?in?which?all?limbs?are?in?flight?or?off?the?ground?(Table?1.1)? (Hildebrand? 1965).??While? not? a? category? for? classifying? gaits,? limb? support? phases?may?also?be?used?to?further?differentiate?between?gait?patterns.??Horses? employ? all? combinations? of? support? including,? single,? bipedal,? tripedal? and? 29 quadrupedal.??In? addition,? these? support? phases? may? be? adjacent? limbs? or? diagonal?limb?combinations?(Leach?et?al.?1987).??? Walk?and?walk?variations.? ? While? the? current? study? is? not? evaluating? the? walk? of? the? stock? breed? western?pleasure?horse,?its?characterization?as?a?stepping?gait?is?important?to?the? evaluation? of? the? jog? (Deuel? 2001).??The? jog? is? defined? as? a? stepping? gait? (Nicodemus?and?Booker?2007;?Nicodemus?and?Clayton?2001a)?but?considered?to? be? a? variation? of? the? trot,? which? is? a? leaping? gait? (Deuel? 2001),? and? creates? confusion?between?scientists?and?industry?personnel?as?to?what?type?of?gait?the? jog? may? be? classified.??Hildebrand? (1965)? developed? a? gait? continuum? that? distinguished? between? symmetrical? gaits? based? on? the? temporal? variables? of? percent?(%)?stride?of?advanced?placement?and?hind?stance.??When?plotting?the? stock? breed? western? pleasure? jog? (46%? lateral? advanced? placement;? 60%? hind? stance)?(Booker?2005;?Nicodemus?and?Booker?2007)?on?Hildebrand?s?continuum,? it? would? fall? in? the? region? between? the? Arabian? jog? (54%? lateral? advanced? placement;? 54%? hind? stance)? and? Quarter? Horse? walk? (33%? lateral? advanced? placement;? 66%? hind? stance)? (Figure? 2.1)? (Hildebrand? 1965;? Nicodemus? and? Booker?2007).??This?positioning?of?the?jog?on?Hildebrand?s?continuum?indicates? that?the?jog?is?more?closely?related?to?the?walk?or?animated?variation?of?the?slow? trot?or?jog,?performed?by?the?Arabian?horse,?than?the?trot?and?places?it?within?the? 30 dotted?area?where?Hildebrand?(1965)?indicated?unusual?gaits?with?no?common? name?(Figure?2.2).??Based?on?this?positioning?it?is?reasonable?to?conclude?that? stock?breed?western?pleasure?horses?are?not?performing?the?jog/trot?or?the?walk? when? jogging,? but? an? altogether? separate? gait? that? has? not? been? appropriately? named.??Both? the? stock? breed? western? pleasure? jog? and? the? walk? have? lateral? footfall?sequences,?and?four?beats,?but?the?jog?has?diagonal?pairs?that?work?as? couplets?where?the?walk?does?not.??Neither?the?stock?breed?western?pleasure?jog? nor?the?walk?has?a?suspension?phase,?and?the?jog?has?an?irregular?rhythm?while? the? walk? has? a? regular? rhythm.??Because? of? the? stock? breed? western? pleasure? horse?s?unique?gait?adaptation,?termed??jog??by?the?equine?industry,?and?its?close? relationship?to?the?walk,?it?is?important?to?understand?the?walk?and?its?variations.? ? ? ? ? ? ? ? ? 31 ? ? Figure?2.1:??The?graph?in?which?nearly?all?symmetrical?gaits?of?horses?fall? (Hildebrand?1965).??The?blue?filled?circle?indicates?the?Quarter?Horse?walk? while?the?orange?filled?square?indicates?the?Arabian?horse?slow?trot.??The? black?filled?triangle?indicates?the?position?where?the?stock?breed?western? pleasure?jog?would?fit?into?the?continuum.??? ? ? ? ? ? ? 32 ? Figure?2.2:??The?relationship?between?symmetrical?gaits?of?horses.??Gaits? that?would?fall?within?areas?indicated?by?dotted?lines?are?unusual?and?have? no?common?name?(Hildebrand?1965).??The?blue?filled?circle?indicates?the? Quarter?Horse?walk?while?the?orange?filled?square?indicates?the?Arabian? horse?slow?trot.??The?black?filled?triangle?indicates?the?position?where?the? stock?breed?western?pleasure?jog?would?fit?into?the?continuum.??? ? ? ? 33 The?foundation?of?all?horse?gaits?is?the?walk.??Defined?as?the?slowest?and? most?complex?of?all?gaits,?the?walk?is?a?four?beat?stepping?gait?characterized?by? no? period? of? suspension? and? an? overlap? between? stance? phases? of? the? limbs? (Deuel? 2001).? Clayton? (1995)? compared? the? collected,? medium,? and? extended? walks?of?dressage?horses?and?found?that?as?the?gait?becomes?more?extended?the? rhythm?becomes?irregular?with?lateral?couplets?so?that?lateral?limbs?move?closely? together?in?time?but?not?synchronously.??? Hodson? et? al.? (1999)? compared? the? collected? and? extended? walks? of? competitive? dressage? horses?to?the?walking?half?pirouette?finding?the?walking? rhythm? of? the? half? pirouette? becomes? irregular? with? periods? of? quadrupedal? support?and?limb?asymmetries.??Asymmetry?and?quadrupedal?support?were?not? present? in? the? collected? and? extended? walks? and? is? most? likely? due? to? the? increased? speed? at? which? the? collected? and? extended? walks? were? performed? when?compared?to?the?walking?half?pirouette.??It?was?concluded?that?the?walking? half? pirouette,? a? half? circle? executed? on? the? haunches? as? the? forehand? moves? around? the? length? of? the? horse?s? body,? was? not? performed? according? to? Federation? Equestre? Internationale? (FEI)? rules? because? it? did? not? maintain? the? same?footfall?sequence,?rhythm,?or?beats?as?the?walk.??Additionally,?each?horse? performed? the? walking? half? pirouette? slightly? different? most? likely? due? to? different? balancing? strategies? (Hodson? et? al.? 1999).??While? this? study? is? not? 34 considering?the?stock?breed?western?pleasure?walk,?neither?the?jog?nor?the?lope?is? performed?according?to?breed?association?definitions?similar?to?the?walking?half? pirouette.??Previous?studies?have?found?periods?of?quadrupedal?support?in?the? stock?breed?western?pleasure?jog?(Nicodemus?and?Booker?2007;?Nicodemus?and? Clayton? 2001a)? and? lope? (Nicodemus? and? Clayton? 2001a)? just? as? periods? of? quadrupedal?support?were?found?in?the?walking?half?pirouette?of?the?dressage? horse? (Hodson? et? al.? 1999).??During? a? half? pirouette,? the? horse? loses? forward? motion?becoming?unbalanced?(Hodson?et?al.?1999),?which?explains?the?presence? of? quadrupedal? support? (Clayton? 1989;? Hodson? et? al.? 1999;? Nicodemus? and? Clayton? 2003).??With? this? in? mind,? it? can? be? suggested? that? the? inclusion? of? quadrupedal?support?during?the?stride?of?stock?breed?western?pleasure?horses?at? the? jog? or? lope? indicates? a? loss? of? balance,? and,? therefore,? a? loss? of? dynamic? stability.????? Temporal?variables?are?a?separate?approach?to?classifying?walk?variations? of?non?gaited?and?gaited?horse?breeds.??Temporal?variables?of?the?slow?and?fast? walks? of? gaited? breeds,? (classic? fino? of? the? Paso? Fino? and? road? gait? of? the? American? Single?Footing? Horse)? indicate? all? walking? gaits? have? four?beats,? regular?rhythm,?and?lateral?footfall?sequences,?but?differentiation?between?gaits? is? facilitated? by? limb? support? and? stance? durations? (Nicodemus? et? al.? 2000).?? Morgan?Park?Horses?were?found?to?demonstrate?a?variation?of?the?walk?called? 35 the?park?walk?which?may?be?performed?with?two?or?four?beats?and?has?no?period? of?suspension?(Nicodemus?et?al.?2001).??While?temporal?variables?have?assisted?in? defining?the?walk?of?non?gaited?horse?breeds,?gaited?horses?have?been?subjected? to?a?greater?number?of?studies?that?evaluated?walking?gaits.??? Temporal?variables,?such?as?footfall?sequence?and?rhythm?have?been?used? to?evaluate?the?gaits?of?gaited?horses,?whose?gaits?have?been?misunderstood?and? incorrectly?defined?for?years?by?the?equine?industry.??Specifically,?fifteen?different? four?beat? stepping? gaits? performed? as? faster? variations? of? the? walk? by? gaited? horse? breeds? were? differentiated? from? each? other? by? examining? temporal? variables.??All?gaits?had?a?lateral?footfall?sequence?and?at?least?one?hoof?on?the? ground?throughout?the?stride,?but?it?was?the?rhythm?and?limb?support?sequences? that? assisted? in? distinguishing? between? these? gaits? (Nicodemus? and? Clayton? 2003).??While?the?majority?of?gaited?horse?studies?have?been?conducted?on?the? Tennessee?Walking?Horse?(TWH),?Nicodemus?and?Clayton?(2001b)?conducted?a? gaited?horse?study?looking?at?the?temporal?variables?of?Paso?Fino?stepping?gaits.?? All? gaits? exhibited? four? beats? and? were? distinguished? by? the? regularity? of? the? rhythm.??Motion?patterns?and?stride?characteristics?of?the?toelt,?a?gait?performed? by?Icelandic?horses,?were?evaluated?at?various?speeds?and?it?was?determined?that? the?toelt?at?all?speeds?was?a?four?beat,?symmetrical?gait?with?alternating?single? and?double?support?phases?(Zips?et?al.?2001).??Temporal?variable?studies?of?the? 36 TWH?have?included:?1)?yearlings?in?training?at?the?flat?walk?(Nicodemus?and? Holt? 2003a);? 2)? foals? at? the? flat? walk? (Nicodemus? and? Holt? 2002);? 3)? 3?gaited,? plantation?shod?horses?at?the?flat?walk,?running?walk,?and?canter?(Nicodemus? and? Holt? 2003b);? and? 4)? the? flat? shod? running? walk? and? the? relationship? of? velocity?on?the?gait?(Nicodemus?et?al.?2002).??A?fifth?study?evaluating?the?walk? and? running? walk? of? the? TWH? determined? that? temporal? variables? of? the? flat? walk?were?similar?to?those?found?in?previous?studies?(Roberson?et?al.?2007).??Each? of?the?TWH?studies?has?assisted?in?defining?the?specific?gaits?and?determining? the?effect?of?variables?on?gait.??? Temporal?variables,?including?the?number?of?beats?per?stride,?rhythm,?and? footfall?sequence,?have?been?used?at?length?to?evaluate?and?define?walking?gaits? for?non?gaited?and?gaited?horses.??Lateral?footfall?sequence?is?the?common?thread? no?matter?which?variation?of?the?walk?is?performed?or?by?which?breed,?and?while? the?stock?breed?western?pleasure?walk?will?not?be?evaluated?in?this?study,?there?is? importance?in?understanding?the?walk?and?its?variations?in?order?to?understand? the?relationship?between?the?walk?and?the?jog.??Additionally,?one?of?the?attempts? of?the?current?study?is?to?address?some?of?the?discrepancies?between?the?breed? definition? guidelines? and? the? scientific? definitions? of? the? stock? breed? western? pleasure?horse?jog,?so?there?is?value?in?understanding?how?temporal?variables? have?been?used?to?appropriately?define?and?evaluate?walking?gaits.??? 37 Trot and trot variations. As?defined?by?Deuel?(2001),?a?trot?is?a?symmetrical,?two?beat?leaping?gait? with? diagonal? pairs.??Holmstr?m? et? al.? (1995)? documented? that? elite? dressage? horses?performing?the?collected?trot?spent?a?greater?percentage?of?stride?on?the? forelimb?(297.5???17.4?ms)?than?when?performing?the?working?trot?(263.5???33.4? ms)?or?trot?in?hand?(227???24.2?ms).??Dressage?horses?performing?the?collected?trot? demonstrate?a?shorter?stride?length?(2.50???4?m)?and?reduced?stride?duration?(783? ??11?ms)?when?compared?to?the?performance?of?working?(2.73???0.04?m;?755???10? ms),?medium?(3.26???0.05?m;?733???17?ms),?or?extended?trots?(3.55???0.07?m;?722??? 15?ms)?(Clayton?1994b).??Parameters?indicating?the?quality?of?the?trot?have?been? used?to?categorize?horses.?? Holmstr?m? et? al.? (1994),? using? stride? length? and? duration,? detected? differences? between? warmblood? riding? horses? judged? as? ?good?? or? ?poor?? trotting?horses.??Horses?classified?as??good??had?a?longer?stride?duration?(794.0??? 13.4?ms?vs.?644.5???40.7?ms)?and?hind?stance?duration?(216.0???7.4?vs.?198.0???4.5? ms)?as?well?as?larger?positive?diagonal?advanced?placement?(29.8???7.6?vs.?11.5??? 5.8?ms)?than?those?classified?as??poor.???Low?stride?frequency?was?correlated?to? longer? stride? duration? and? is? required? for? good? gait? quality? (Back? et? al.? 1994;? Barrey? 1999;? Holmstr?m? et? al.? 1994).??Large? positive? diagonal? advanced? placements?may?be?an?indicator?of?a?horse?s?balance?and?ability?to?carry?more? 38 weight? on? the? hindlimbs? (Back? et? al.? 1994;? Holmstr?m? et? al.? 1993,? 1994,? 1995).?? While?warmblood?and?stock?breed?horses?are?physically?different,?both?breeds? have?the?ability?to?perform?a?collected?adaptation?of?the?trot.??Therefore,?when? comparing?the?jog?of?the?stock?breed?western?pleasure?horse?to?the?warmblood,? stock?breed?western?pleasure?horses?had?a?longer?stride?duration?(921???34?ms)? and? hind? stance? (559? ?? 47? ms)? than? those? classified? as? ?good?? trotters,? which? indicates?that?stock?breed?western?pleasure?horses?would?be?classified?as??good.???? However,? the? jog? had? a? negative? diagonal? advanced? placement,? longer? fore? stance?duration?(626???40?ms),?and?a?considerable?percent?of?stride?was?spent?in? tripedal? with? two? forelimb? support? (19? ?? 9%),? which,? unlike? the? ?good?? trot,? indicates?that?the?stock?breed?western?pleasure?horse?carried?more?weight?on?the? forelimbs,? or? forehand,? than? the? hindlimbs? during? the? jog? (Booker? 2005;? Nicodemus?and?Booker?2007).??? Gait?parameters?for?determining?the?quality?of?gait?as?mature?adult?horses? are?possibly?set?as?foals?(Back?et?al.?1994).??Dutch?Warmblood?foal?locomotion?at? the?trot?has?been?quantified?finding?kinematic?parameters?such?as?velocity,?stride? and?stance?duration,?stride?length,?and?joint?ranges?of?motion?for?the?shoulder? (humeral),? elbow? (cubital),? carpus? (antebrachiocarpal,? midcarpal,? carpometacarpal,?and?intercarpal),?and?fetlock?(metacarpophalangeal)?joints?are? set? as? early? as? 4? months? of? age.??Video? analysis? measured? the? kinematics? of? 39 superior?gait?in?young?trotting?Warmbloods?to?identify?criteria?for?determining? good?or?superior?gait?qualities.??Superior?gait?qualities?determined?at?a?young?age? may?reflect?future?performance?in?the?show?ring;?results?showed?that?fore?and? hindlimb?stride?and?swing?phases?correlated?with?aspects?of?a?gait?score?such?as? length,? suppleness,? and? strength? that? are? judged? visually.??As? well,? judging? scores? correlated? strongly? with? limb? durations,? protraction/retraction? angles,? scapular?angles,?forelimb?fetlock?angles,?stifle?angles,?and?tarsal?angles.??Horses? were? judged? as? well? as? scored? objectively? using? kinematics,? and? the? ranking? given? based? on? kinematics? closely? simulated? subjective? rankings? by? judges.?? Further? research? on? kinematic? response? in? trotting? Warmbloods? to? a? 70?day? training?period?found?that?limb?durations?and?protraction/retraction?angles?were? significantly?different?following?training?(Back?et?al.?1995).??Along?with?kinematic? changes? due? to? training,? studies? have? shown? kinematic? changes? including? increased?stride?length?and?flexion?of?the?shoulder,?elbow,?and?carpus?occur?with? growth?in?trotting?Andalusian?foals?as?they?aged?up?to?24?months?(Cano?et?al.? 2001).??A?horse?s?age?influences?gait,?but?the?mechanics?of?gait?development?as?a? horse? ages? has? not? been? kinematically? determined? (Barrey? 1999).??Measuring? locomotor? and? physiological? parameters? could? help? predict? the? future? performance?of?young?horses.??? 40 As?with?the?walk,?temporal?variables?of?the?trot?as?performed?by?different? breeds?and?types?of?horses?has?been?useful?in?defining?and?classifying?the?trot? and?its?variations.??Temporal?variables?have?been?used?to?define?the?trot?of?the? hunter?type?Arabian?and?Quarter?Horse?(Nicodemus?2007;?Nicodemus?and?Slater? 2006).??The?Arabian?hunter?trot?was?defined?as?a?leaping?gait?(suspension:??16??? 3%? of? stride)? with? symmetry? because? the? limbs? moved? in? diagonal? pairs? (Nicodemus?and?Slater?2006);?hunter?type?Quarter?Horses?also?performed?the?trot? as?a?leaping?gait?(suspension:?19???1%)?with?symmetry?because?the?limbs?moved? as?diagonal?pairs?(Nicodemus?2007).??During?stance?phase?Arabian?horses?used? diagonal? bipedal? limb? support? (84? ?? 3%)? but? most? of? the? stride? was? spent? in? swing?phase?(fore?stance:??40???3%,?hind?stance:??44???1%)?(Nicodemus?and?Slater? 2006);? Quarter? Horses? spent? a? comparable? time? to? that? of? the? Arabian? hunter? pleasure?horse?in?diagonal?bipedal?support?(81???1%)?(Nicodemus?2007).??Arabian? horses?performed?the?trot?with?a?velocity?of?2.36???0.07?m/s,?stride?duration?of?718? ??16?ms,?and?stride?length?of?1.70???0.04?m?while?Quarter?Horses?performed?with? a?velocity?of?2.83???0.31?m/s,?stride?duration?of?773???43?ms,?and?stride?length?of? 2.19???0.25?m.????The?hunter?trot?of?the?Arabian?and?Quarter?Horse?was?performed? as? a? similar? gait? when? comparing? velocity,? stride? length,? and? stride? duration? across? breeds.??These? similarities? indicate? that? the? hunter? trot? has? similar? gait? parameters?between?the?Arabian?and?Quarter?Horse?breeds,?so?whether?or?not? 41 the? horses? are? the? same? breed,? the? hunter? trot? is? similar? when? performed? negating?the?differences?in?conformation?and?gait?style?between?the?Arabian?and? Quarter?Horse.??Quarter?(stock)?Horses?also?perform?the?western?pleasure?jog,? which?is?considered?to?be?a?variation?of?the?collected?trot?by?the?equine?industry? and?science,?but?by?scientific?definition,?the?jog?cannot?be?a?variation?of?the?trot? because?the?jog?is?classified?as?a?stepping?gait?while?the?trot?is?a?leaping?gait.?? Performance? of? the? collected? trot? and? other? trot? variations? further? solidify? the? scientific?argument?that?the?jog?is?not?a?variation?of?the?trot.??? Trot?variations?performed?by?dressage?horses?include?the?piaffe,?passage,? collected,? working,? medium,? extended,? and? flying? trot? (Clayton? 1994b,? 1997;? Weishaupt?et?al.?2009).??Clayton?(1997)?classified?the?collected?trot,?passage,?and? piaffe?as?symmetrical?gaits.??The?passage?and?piaffe?were?determined?to?have? considerable? variations? in? fore? and? hind? stance? duration,? suspension,? and? diagonal? advanced? lift?off? between? individual? horses,? and? both? gaits? can? be? distinguished?from?the?collected?trot?through?stride?duration?differences.??While? the? collected,? medium,? working,? extended,? and? flying? trots? exhibit? diagonal? pairs,? the? passage? demonstrates? diagonal? couplets? with? the? hindlimbs? always? impacting?the?ground?before?the?diagonal?forelimb.??The?passage?is?performed?at? a?slower?velocity?than?the?trot?with?an?increase?in?collection?and?a?more?vertical? movement? than? forward? movement? (Clayton? 1997;? Weishaupt? et? al.? 2009).?? 42 Diagonal?couplets?seen?in?the?passage?are?likely?due?to?the?slow?velocity?in?which? the?gait?is?performed.??If?the?reduction?in?speed?results?in?diagonal?couplets?in?the? passage?of?dressage?horses?it?is?reasonable?to?conclude?that?the?diagonal?couplets? seen?in?the?stock?breed?western?pleasure?horse?jog?are?also?due?to?velocity.? A?specific?trot?adaptation?includes?the?jog?performed?by?western?pleasure? horses.??Nicodemus? and? Clayton? (2001a)? and? Nicodemus? and? Booker? (2007)? found?that?the?jog?of?stock?breed?western?pleasure?horses?had?a?four?beat?gait? with? lateral? footfall? sequence? and? irregular? rhythm? with? diagonal? couplets.?? Likewise,?Arabian?and?Morgan?western?pleasure?horses?performed?the?jog?with? four?beats,?lateral?footfalls,?and?irregular?rhythm?(Nicodemus?and?Luckett?2008).?? Limbs?during?the?jog?rarely?had?lift?off?or?contact?with?the?ground?at?precisely? the? same? time,? which? gave? the? gait? an? irregular? rhythm? (Hildebrand? 1965).?? Stride?duration?was?found?to?be?similar?between?jogs?(Nicodemus?and?Clayton:? 951? ?? 44.9? ms;? Nicodemus? and? Booker:? 921? ?? 34? ms;? Nicodemus? and? Luckett:?? Arabian?=?921???48?ms,?Morgan?=?971???42?ms)?performed?by?western?pleasure? horses? no? matter? their? breed.??In? all? previously? cited? studies,? horses? demonstrated?a?period?of?quadrupedal?limb?support?during?the?jog.??The?four? beat? rhythm,? due? to? diagonal? couplets,? and? lack? of? suspension? should,? by? definition,? classify? the? jog? as? a? stepping? gait? in? contrast? to? the? leaping? gait? classification?of?the?trot?(of?which?the?jog?is?a?variation)?(Nicodemus?and?Booker? 43 2007).??Diagonal?couplets?create?the?illusion?of?synchronization?in?diagonal?pairs? during?the?jog?because?the?fore?and?hind?limbs?on?opposite?sides?of?the?body? moved?closely?together?and?strike?the?ground?at?nearly?the?same?time.?? Other?trot?like?equine?gaits?demonstrate?diagonal?couplets?as?seen?in?stock? breed?western?pleasure?horses.??Early?studies?by?Grogan?(1951)?and?Hildebrand? (1965)?state?that?Standardbred?trotters?and?pacers?may?display?diagonal?or?lateral? couplets?with?the?hindlimb?striking?slightly?before?the?forelimb.??Holmstr?m?et.?al? (1995)?determined?that?elite?dressage?horses?performing?at?the?collected?trot?may? display?couplets?and?have?placement?of?the?fore?or?hind?limb?of?the?diagonal?pair? slightly?before?the?other?limb.??Another?dressage?study?found?that?when?high? speed?cinematography?was?used,?a?slight?diagonal?pair?disassociation?was?seen? at?impact?with?the?fore?or?hindlimb?moving?in?advance?(Clayton?1994b).??Paso? Fino? horses? perform? the? paso? corto? and? paso? largo? as? stepping? gaits? with? diagonal? couplets? similar? to? the? stock? breed,? Arabian,? and? Morgan? western? pleasure? jog? (Nicodemus? and? Booker? 2007;? Nicodemus? and? Clayton? 2001a,? b;? Nicodemus?and?Luckett?2008).??Diagonal?and?lateral?couplets?are?also?seen?in?the? Icelandic?horses?performing?the?toelt,?although?breed?standards?require?a?regular? rhythm.??Additionally,?the?toelt?is?described?by?the?industry?as?a?gait?with?no? suspension? (FEIF? 2009),? but? a? small? percentage? of? horses? showed? suspension? when? performing? the? toelt? with? suspension? increasing? as? speed? increased? 44 (Biknevicius?et?al.?2006;?Zips?et?al.?2001),?and?may?be?performed?at?speeds?ranging? from?0.89?to?5.98?m/s?with?a?lateral?footfall?sequence?(Biknevicius?et?al.?2006).??The? Icelandic?Horse?Association?considers?suspension?during?the?stride?of?the?toelt?a? fault;?however,?some?Icelandic?horses?are?performing?the?toelt?with?suspension.?? Similarly,?stock?breed?western?pleasure?horses?are?not?performing?the?jog?with?a? period?of?suspension?even?though?major?stock?breed?association?gait?definitions? for?the?jog?imply?that?the?gait?should?have?suspension.??This?lack?of?suspension? and? diagonal? couplets? seen? in? the? jog? of? stock? breed,? Arabian,? and? Morgan? western?pleasure?horses?likens?the?gait?more?to?the?fox?trot?performed?by?the? Missouri?fox?trotting?horse.? The? fox? trot? performed? by? the? Missouri? Fox? Trotter? has? no? period? of? suspension?and?is?diagonal?in?rhythm?due?to?diagonal?couplets?but?has?a?lateral? footfall?sequence.??Limb?support?phases?of?the?fox?trot?included?tripedal?with?two? hindlimbs? and? with? two? forelimbs? and? diagonal? and? lateral? bipedal? supports? (Clayton?and?Bradbury?1995;?Nicodemus?and?Clayton?2003).??Stride?duration?and? forelimb? stance? was? longer? for? the? Nicodemus? and? Clayton? (2003)? study? than? that? of? the? Clayton? and? Bradbury? (1995)? study? (Table? 2.1).??The? difference? in? stride?duration?seen?in?the?two?previously?mentioned?studies?for?the?fox?trot?is? most? likely? due? to? the? velocity? of? the? Missouri? Fox? Trotters;? stride? duration? decreases? as? velocity? increases,? so? it? is? reasonable? to? conclude? that? the? horses? 45 used?in?the?Clayton?and?Bradbury?(1995)?study?were?traveling?at?a?faster?rate? than?those?in?the?Nicodemus?and?Clayton?(2003)?study.??The?jog?performed?by? the?western?pleasure?horse?is?closely?related?to?the?fox?trot?of?the?Missouri?Fox? Trotter? in? limb? support,? footfall? sequence,? and? rhythm? because? both? have? diagonal?couplets?and?longer?periods?of?diagonal?bipedal?support?(Clayton?and? Bradbury? 1995;? Nicodemus? and? Booker? 2007;? Nicodemus? and? Clayton? 2001a).?? Similar? limb? support? phases? between? the? fox? trot? and? stock? breed? western? pleasure?jog?included?tripedal?with?two?hindlimbs?and?two?forelimbs?as?well?as? diagonal?and?lateral?bipedal?supports.??However,?stock?breed?western?pleasure? horses?had?a?considerably?longer?stride?duration?and?forelimb?stance?time?than? did?the?Missouri?Fox?Trotting?horse?(Table?2.1).??The?combination?of?longer?stride? duration? and? forelimb? stance? time? for? the? stock? breed? western? pleasure? horse? may? be? due? to? the? horse?s? headset? being? considerably? lower? than? that? of? the? Missouri?Fox?Trotter.??Neither?the?stock?breed?western?pleasure?jog?nor?the?fox? trot?has?a?period?of?suspension.??For?both?the?fox?trot?and?the?jog,?the?lack?of? suspension?means?there?is?no??bounce??in?the?stride?and?allows?for?a?smoother,? more?comfortable?ride.??It?is?the?synthesis?of?these?scientific?data?that?has?shown? that?the?jog?of?the?stock?breed?western?pleasure?horse,?a?non?gaited?horse?breed,? is?closely?related?to?the?fox?trot?of?the?Missouri?Fox?Trotter,?a?gaited?horse?breed.??? ? 46 ? Table?2.1:??Means?(SD)?for?stride?duration?(ms)?and?forelimb?stance?(%)?of?the?fox? trot?as?performed?by?the?Missouri?Fox?Trotter?and?jog?as?performed?by?the?stock? breed? western? pleasure? horse? (Clayton? and? Bradbury? 1995;? Nicodemus? and? Booker?2007;?Nicodemus?and?Clayton?2001a;?Nicodemus?and?Clayton?2003). Fox?Trot? Jog? ? Clayton? and? Bradbury? (1995)? Nicodemus? and? Clayton? (2003)? Nicodemus? and? Clayton? (2001a)? Nicodemus? and?Booker? (2007)? Stride?Duration?(ms)? 593?(17.40)? 639?(27)? 951?(44.9)? 921?(34)? Forelimb?Stance?(%)? 54.7?(1.80)? 58?(4)? 66?(7)? 68?(3)? The? Dutch? Warmblood? trot? and? stock? breed? western? pleasure? jog? have? also? been? evaluated? using? joint? kinematics.??Dutch? Warmbloods? at? the? trot? demonstrated?peak?flexion?angles?of?146???9.6 o ?for?the?fetlock,?109.7???5.9 o ,?for?the? carpus,?110.1???3.4 o ?for?the?elbow,?and?115.5???2.9 o ?for?the?shoulder?with?most?of? the? motion? occurring? during? swing? phase? (Lanovaz? et? al.? 1999).??Stock? breed? western?pleasure?horses?at?the?jog?flexed?the?carpus?(116.18???11.2 o )?and?fetlock? (181.19? ?? 8.3 o )? less? than? Dutch? Warmbloods,? while? showing? similar? shoulder? (114.69???3.93 o )?and?greater?elbow?flexion?(104.33???7.44 o )?(Nicodemus?and?Booker? 2007).??Differences?seen?between?trotting?Warmbloods?and?jogging?stock?breed? western? pleasure? horses? indicate? the? Warmbloods?? forelimb? range? of? motion? (ROM)? may? be? initiated? at? the? carpus? and? fetlock? joints? while? the? western? 47 pleasure?horse?s?motion?may?be?initiated?at?the?elbow?joint.??Both?breeds?utilized? the?shoulder?joint?for?forelimb?ROM.??Limited?flexion?of?the?carpus?and?fetlock? (Figure? 1.4)? was? found? in? the? stock? breed? western? pleasure? horse? and? is? consistent? with? judging? standards? because? the? horse?s? knees? should? be? flat? moving?during?the?jog?and?fetlocks?should?minimize?spring?and?lift?of?the?body? (Nicodemus?and?Booker?2007).??? The? trot? and? its? variations? are? performed? differently? when? evaluating? horses?within?and?between?breeds;?additionally,?the?visual?image?is?sometimes? deceiving,? so? it? is? important? to? evaluate? gait? based? on? scientific? parameters.?? Stride?length?and?duration,?velocity,?diagonal?advanced?placements?and?lift?offs,? and?limb?stance?phases?may?all?be?utilized?to?objectively?quantify?and?define?the? trot?and?it?is?variations.??While?the?stock?breed?western?pleasure?jog?has?been? subject? to? scientific? analyses? (Nicodemus? and? Booker? 2007;? Nicodemus? and? Clayton? 2001a),? the? extended? jog? has? not? been? evaluated.??Accurately? differentiating?between?the?collected?and?extended?jog?of?the?stock?breed?western? pleasure?horse?is?important?to?the?equine?industry?for?clinical?and?performance? applications?and?will?assist?in?understanding?gait?definitions?in?order?for?gaits?to? be?either?performed?according?to?breed?guidelines?or?for?the?gait?definitions?to?be? changed?to?better?reflect?what?horses?are?performing.? 48 Canter?and?canter?variations.? Stock? breed? western? pleasure? horses? perform? the? lope,? which? is? considered? by? science? and? the? industry? to? be? a? variation? of? the? canter? and? synonymous? with? the? collected? canter? of? the? dressage? horse.??While? the? similarities? of? asymmetry? as? well? as? leading? and? trailing? limbs? exist? between? performance?of?the?canter?and?the?lope,?the?lope?is?a?stepping?gait?because?there? is? not? period? of? suspension? (Nicodemus? and? Booker? 2007;? Nicodemus? and? Clayton? 2001a)? and? the? canter? is? considered? a? leaping? gait? because? there? is? a? period? of? suspension? in? the? medium? and? extended? canter? performed? by? the? dressage?horse?(Clayton?1994a).??However,?the?lack?of?suspension?found?in?the? collected? canter? of? elite? dressage? horses? and? the? lope? of? stock? breed? western? pleasure? horses? might? explain? why? the? western? pleasure? lope? is? commonly? referred? to? as? a? collected? canter? (Clayton? 1994a;? Nicodemus? and? Booker? 2007;? Nicodemus?and?Clayton?2001a).??Based?on?the?acceptance?of?stock?breed?western? pleasure?lope?being?a?variation?of?the?canter,?it?is?important?to?understand?how? the?canter?and?its?variations?are?performed.? ?The?canter?is?a?three?beat?asymmetrical?gait?with?a?footfall?sequence?of?a? trailing?hind,?diagonal?pair,?and?leading?forelimb.??The?trailing?limbs?are?defined? as?the?first?of?two?fore?or?hindlimbs?to?touch?and?leave?the?ground?during?each? stride?of?asymmetrical?gaits;?whereas,?leading?limbs?are?the?second?of?two?fore?or? 49 hindlimbs?to?touch?and?leave?the?ground?(Deuel?2001).??Similarities?in?stance?and? swing?duration?have?been?found?between?horses?cantering?on?the?left?lead?and? those?on?the?right?lead?(Back?et?al.?1997).??Dutch?Warmbloods?were?used?in?gait? studies? to? quantify? and? set? parameters? such? as? velocity,? stride? length,? stride? duration,?stance?duration,?and?scapula,?elbow,?carpus,?and?fetlock?joint?angles?of? the?canter?(Back?et?al.?1993)?and?to?determine?flexion/extension,?lateral?bending,? and? axial? rotation? of? the? spine? during? the? canter? (Faber? et? al.? 2001).??Further? canter?studies?compared?the?extended?canter?in?horses?trained?for?dressage?to? those?trained?for?racing?and?found?differences?between?velocity,?stance?durations? and?overlaps,?suspension,?and?time?between?impacts?of?the?diagonal?pair?due?to? training.??Specifically,? racehorses? had? longer? suspension? phases? and? shorter? stance? durations? and? limb? overlaps? when? performing? the? extended? canter? (Clayton? 1993).??Nicodemus? (2007)? looked? at? the? hunter? canter? of? the? Quarter? Horse? and? found? that? the? trailing? fore? and? leading? hindlimb? worked? as? a? diagonal?pair?because?each?limb?spent?the?same?amount?of?time?in?stance?(fore:?? 46???5%;?hind:??46???5%);?the?leading?forelimb?(42???4%)?and?trailing?hindlimb?(41? ??3%)?spent?less?time?in?stance?phase.??Limb?support?phases?throughout?the?stride? included?suspension,?diagonal?bipedal,?single?fore,?single?hind,?and?tripedal?with? two?forelimbs?(Nicodemus?2007).??The?canter?is?performed?differently?based?on? breed?and?type?of?horse?within?breed;?further,?variations?of?the?canter?exist.??? 50 The? canter? may? be? performed? as? a? collected,? medium,? extended,? or? disunited? gait? with? all? variations? having? periods? of? suspension.??Advanced? placement? in? the? dressage? canter? was? found? to? be? the? longest? between? the? leading? fore? and? trailing? hindlimb? for? the? medium? and? extended? canters;? however,? a? period? of? suspension? was? found? during? this? phase? between? placement? of? the? leading? fore? and? trailing? hindlimb? in? dressage? horses? at? the? canter? (Clayton? 1994a)? that? is? not? present? in? the? plantation? shod? TWH? canter? (Nicodemus?and?Holt?2003b),?or?stock?breed?western?pleasure?lope,?which?is?a? canter?variation?(Nicodemus?and?Booker?2007;?Nicodemus?and?Clayton?2001a).?? Advanced?placement?of?the?leading?fore?and?trailing?hindlimb?shortened?for?the? working? canter,? and? at? the? collected? canter? no? suspension? was? recorded? for? advanced? dressage? horses.??Stride? length? and? duration? as? well? as? velocity? for? dressage?horses?at?the?canter?was?1.98?m,?609?ms,?and?3.27?m/s?for?collected;?2.35? m,?608?ms,?and?3.91?m/s?for?working;?2.93?m,?595?ms,?and?4.90?m/s?for?medium;? and?3.46?m,?572?ms,?and?5.97?m/s?for?extended?(Clayton?1994a).???? Considered?to?be?another?variation?of?the?canter?is?the?lope?of?the?western? pleasure?horse.??Research?has?found?that?western?pleasure?horses?demonstrated?a? four?beat? lope,? lateral? footfall? sequence,? and? no? periods? of? suspension? (Nicodemus? and? Williams? 2009;? Nicodemus? and? Clayton? 2001a).??Stock? breed? western? pleasure? horses? perform? the? lope? as? a? four?beat? stepping? gait? but? a? 51 period?of?quadrupedal?support?(2%?of?stride)?was?found?in?the?Nicodemus?and? Clayton?(2001a)?study?unlike?the?horses?in?Nicodemus?and?Booker?(2007)?where? no? (0%)? quadrupedal? support?was?found.??It?should?be?noted?that?differences? seen?between?the?two?stock?breed?western?pleasure?horse?studies?may?be?due?to? changes?in?show?trends?from?2001?to?2007.??Interestingly,?Arabian?and?Morgan? western? pleasure? horses? also? do? not? show? a? period? of? quadrupedal? support? during?the?lope?(Nicodemus?and?Williams?2009).??The?lope?was?performed?with?a? velocity?of?1.74???0.13?m/s?and?stride?duration?of?715???38?ms?(Nicodemus?and? Booker,?2007);?Nicodemus?and?Clayton?(2001a)?found?a?stride?duration?of?721.4??? 26.7?ms,?which?was?longer?than?the?stride?duration?found?by?Nicodemus?and? Booker?(2007)?and?indicates?that?horses?in?the?Nicodemus?and?Booker?study?were? traveling? at? a? faster? velocity? than?those?in?the?Nicodemus?and?Clayton?study.? Velocity?was?slower?and?stance?duration?was?longer?for?the?stock?breed?western? pleasure?horse?lope?than?for?the?collected?canter?of?the?dressage?horse?(velocity?=? 3.27?m/s;?stance?duration?=?609?ms)?(Clayton?1994a)?however,?the?equine?industry? considers? these? gaits? to? be? synonymous.??Based? on? the? velocity? and? stance? durations? it? is? possible? that? the? stock? breed? western? pleasure? lope? was? misclassified? by? the? equine? industry? because? of? its? visual? similarities? to? the? collected?canter?of?the?dressage?horse.???Limb?support?throughout?the?stride?of? the?stock?breed?western?pleasure?lope?was?diagonal?and?lateral?bipedal,?unipedal? 52 fore?and?hind,?and?tripedal?with?two?fore?and?two?hindlimbs,?and?horses?spent? the?greatest?percentage?of?this?stride?in?diagonal?bipedal?support?(44???6%),?just? as?observed?in?the?collected?canter?of?the?dressage?horse,?however,?the?velocity?is? the?telling?variable.??? Other? similarities? exist? between? the? Nicodemus? and? Booker? (2007)? and? Nicodemus?and?Clayton?(2001a)?studies?for?stance?durations?for?the?leading?hind? (2001a?=?59???4%,?2007?=?60???3%),?leading?fore?(2001a?=?62???1%,?2007?=?57???6%),? and? trailing? forelimb? (2001a? =? 62? ?? 1%,? 2007? =? 59? ?? 5%).??However,? the? limb? beginning?the?stride?cycle?for?the?lope,?the?trailing?hind,?was?found?to?have?a? longer?stance?duration?during?the?Nicodemus?and?Clayton?(2001a)?lope?(69???2%)? when?compared?to?the?Nicodemus?and?Booker?(2007)?(50???4%)?study.??Similar? limb?support?phases?between?the?lope?in?Nicodemus?and?Clayton?(2001a)?and?the? Nicodemus?and?Booker?(2007)?study?include?single?forelimb,?diagonal?and?lateral? bipedal,? and? tripedal? with? two? fore? and? two? hindlimbs.? Advanced? placement? was?found?in?stock?breed?western?pleasure?horses?at?the?lope?to?be?the?shortest? between? the? leading? fore? and? trailing? hindlimb,? the? period? where? suspension? usually? occurs? (Nicodemus? and? Booker,? 2007),? instead? of? being? the? longest? as? seen? in? the? Nicodemus? and? Clayton? (2001a)? study.??Nicodemus? and? Clayton? (2001a)? completed? the? temporal? variable? study? of? the? stock? breed? western? pleasure?lope?before?stock?breed?associations?attempted?to?improve?performance? 53 of?the?gait?by?including?the??forward?motion??clause?in?the?gait?definition.??The? Nicodemus? and? Booker? (2007)? evaluation? of? the? stock? breed? western? pleasure? lope? occurred?after?the?definition?change?by?breed?associations.??Comparisons? between? the? two? western? pleasure?studies?indicate?that?while?there?was?some? improvement?in?the?lope,?such?as?no?quadrupedal?support,?after?the?rule?changes? the?lope?was?still?not?being?performed?according?to?breed?association?guidelines.?? The?disassociation?of?the?diagonal?pair?gives?the?gait?four?beats?rather?than?three? and?likens?the?gait?to?the?canter?of?the?plantation?shod?TWH.? The? canter? of? the? plantation? shod? TWH? was? found? to? be? a? four?beat? stepping?gait?(Nicodemus?and?Holt,?2003a)?and?performed?at?a?velocity?of?3.8??? 0.7?m/s?and?a?stride?duration?of?679???58?ms;?stock?breed?western?pleasure?horses? perform? the? lope? at? a? slower? velocity? (1.74? ?? 0.13? m/s)? and? a? longer? stride? duration? (715? ?? 38? ms)? than? the? TWH? performs? the? canter? (Nicodemus? and? Booker? 2007).??Both? the? TWH? canter? and? stock? breed? western? pleasure? lope? exhibited?diagonal?and?lateral?bipedal,?unipedal?fore?and?hind,?and?tripedal?with? two?fore?and?two?hindlimb?limb?support?phases.??The?TWH?spent?the?greatest? percentage? of? stride? in? lateral? bipedal? support? (34%),? while? the? stock? breed? western?pleasure?horses?performed?with?diagonal?bipedal?support?(44???6%)?as? the?greatest?percentage?of?stride.??Splan?and?Hunter?(2003)?continued?TWH?gait? studies? by? comparing? the? canter? of? horses? trained? for? performance? classes? to? 54 those?trained?for?light?shod?classes.??Stock?breed?western?pleasure?horses?perform? the?lope?with?a?stride?duration?between?that?of?the?performance?(879???0.183?ms)? and?light?(654??0.006?ms)?shod?TWH?canter.??Performance?(38.25???1.67%)?and? light? (22.73? ?? 2.01%)? shod? horses? spent? a? great? percent? of? stride? in? diagonal? bipedal? support? just? as? the? stock? breed? western? pleasure? horse.??Limb? stance? durations?for?the?lope?(trailing?fore?=?59???5%,?leading?fore?=?57???6%,?trailing?hind? =?50???4%,?leading?hind?=?60???3%)?were?longer?than?the?limb?stance?durations?for? the? performance? trained? (trailing? fore? =? 41.32? ?? 0.54%,? leading? fore? =? 38.07? ?? 0.80%,?trailing?hind?=?48.86???1.15%,?leading?hind?=?49.03???0.43%)?and?light?shod? trained?TWH?(trailing?fore?=?37.89???0.79,?leading?fore?=?26.38???1.20%,?trailing? hind?=?48.07???1.20%,?trailing?fore?=?37.89???0.79%)?performing?the?canter.??The? low,?flat?line?of?motion?required?in?stock?breed?western?pleasure?necessitates?a? lower,?shorter?limb?swing?phase.??In?the?TWH?canter?studies,?light?shod?horses? exhibited?suspension,?but?plantation?and?performance?shod?horses,?similar?to?the? stock? breed? western? pleasure? horse? at? the? lope,? performed? the? canter? with? no? period? of? suspension? (Nicodemus? and? Booker? 2007;? Nicodemus? and? Clayton? 2001a;?Splan?and?Hunter?2004).??In?short,?the?stock?breed?western?pleasure?horse? performs? the? lope? with? similarities? and? differences? between? the? plantation,? performance,? and? light? shod? TWH.??The? velocity? of? the? stock? breed? western? pleasure?horse?is?slower?than?that?of?the?plantation?shod?TWH,?but?performed? 55 with? a? stride? duration? between? that? of? the? performance? and? light? shod? TWH.?? Limb? support? phases? between? the? stock? breed? western? pleasure? lope? and? the? plantation,? performance,? and? light? shod? TWH? are? similar? with? the? greatest? similarities? to? the? stock? breed? western? pleasure? lope? found? in? the? amount? of? diagonal? bipedal? support? seen? in? the? performance? and? light? shod? TWH.?? However,? the? stock? breed? western? pleasure? horse? had? longer? limb? stance? durations?than?either?the?performance?or?light?shod?TWH.??? In?addition?to?temporal?variables,?kinematic?measures?have?been?used?to? evaluate? Dutch? Warmbloods? at? the? canter? and? stock? breed? western? pleasure? horses? at? the? lope.??Leading? forelimb? joints? of? Warmbloods? at? the? canter? had? greater?ROM?with?more?distinctive?flexion?peaks?for?the?shoulder?and?fetlock;? more?gradual?flexion?peaks?of?the?elbow,?carpus,?and?fetlock;?and?more?gradual? extension?peaks?for?the?elbow?than?did?the?stock?breed?western?pleasure?horse?s? leading? forelimb.??Both? the? elbow? and? carpus? demonstrated? close? pattern? similarities,? while? the? fetlock? of? the? stock? breed? western? pleasure? horse? demonstrated?a?double?peak?of?extension?during?stance?that?was?not?present?in? the?canter.??In?stock?breed?western?pleasure?horse?s?leading?hindlimb,?the?stifle? (femoropatellar? and? femorotibial),? hock? (proximal?intertarsal,?distal?intertarsal,? tarsometatarsal,?and?tarsocrural),?and?fetlock?joints?demonstrated?less?ROM?than? the?Warmblood?canter,?while?the?hip?(coxofemoral)?showed?similar?ROM.??The? 56 hip?and?stifle?flexed?and?extended?more?gradually?throughout?the?lope?stride,? similar?to?the?patterns?demonstrated?during?the?Dutch?Warmblood?canter?for?the? hip?and?stifle?joints.??Less?distinction?was?seen?during?flexion?peaks?of?stance?and? swing?for?the?hock?joint?at?the?lope,?which?demonstrated?a?similar?motion?pattern? to? the? canter? of? the? Dutch? Warmblood.??Fetlock? flexion? peaks? were? less? distinctive?at?the?lope,?and?the?fetlock?lacked?a?double?peak?of?flexion?during?the? loping?swing?phase?that?was?present?in?the?Warmblood?canter?(Back?et?al.?1997;? Nicodemus?and?Booker?2007).??Both?the?canter?and?lope?were?performed?with?a? high? degree? of? engagement? from? the? hindquarters,? which? may? explain? the? similarity?in?joint?motion?of?the?leading?hindlimbs?of?the?Dutch?Warmblood?and? the?stock?breed?western?pleasure?horse.??Slower?velocity?of?the?lope?and?lack?of? suspension,? when? compared? to? the? canter,? may? explain? the? decrease? in? joint? ROM?and?more?gradual?and?less?distinctive?flexion?and?extension?peaks.??? The?canter?and?its?variations?are?performed?differently?when?evaluating? horses?within?and?between?breeds;?however,?asymmetry?and?leading?limbs?are? always? present? no? matter? the? variation.??Stride? length? and? duration,? velocity,? advanced? placements? and? lift?offs,? and? limb? stance? phases? are? all? utilized? to? objectively?quantify?and?define?the?canter?and?the?variations.??While?the?stock? breed?western?pleasure?lope?has?been?subjected?to?scientific?analysis?(Nicodemus? and?Booker?2007;?Nicodemus?and?Clayton?2001a),?the?extended?lope?has?not?been? 57 evaluated.??Based? on? previous? research? (Nicodemus? and? Booker? 2007;? Nicodemus?and?Clayton?2001a)?that?indicates?that?stock?breed?western?pleasure? horses? do? not? exhibit? a? period? of? suspension? further? analysis? is? warranted? to? accurately? differentiate? between? the? collected? and? extended? lope? of? the? stock? breed? western? pleasure? horse.??The? importance? of? correctly? identifying? loping? gaits? of? stock? breed? western? pleasure? horses? has? clinical? and? performance? applications;? correct? gait? identification? will? assist? in? understanding? gait? definitions? so? that? the? lope? may? either? be? performed? according? to? breed? guidelines?or?for?the?gait?definition?to?be?changed?to?better?reflect?how?horses?are? performing?the?lope.? In? summary,? by? defining? gaits? using? temporal? variables? and? kinematic? analysis,?researchers?have?created?an?objective?basis?for?comparison?of?gaits?and? horses?between?and?within?breeds.??Gait?analysis?defines?footfall?sequence,?limb? support,? rhythm,? stride? durations,? displacements,? and? joint? angles? of? the? gait.?? Stock? breed? western? pleasure? horses? have? been? the? subject? of? several? studies? (Nicodemus? and? Booker? 2007;? Nicodemus? and? Clayton? 2001a);? however,? discrepancies? still? exist? between? the? industry? and? scientific? definitions? and? classifications?of?the?stock?breed?western?pleasure?jog?and?lope.??Because?change? takes? time,? gait? classifications? are? not? likely? to? be? affected? in? the? near? future;? however,?through?the?presentation?of?research?and?dissemination?of?information? 58 regarding?these?inconsistencies,?perhaps?change?can?be?enacted?that?will?provide? more?consistent?gait?definitions.??Further,?the?extended?jog?and?lope?have?yet?to? be? evaluated? scientifically.??Kinematic? research? associated? with? stock? breed? western?pleasure?is?important?to?the?equine?industry?for?clinical?and?performance? applications?and?will?assist?in?understanding?gait?definitions?in?order?for?gaits?to? be?either?performed?according?to?breed?guidelines?or?for?the?gait?definitions?to?be? changed?to?better?reflect?what?horses?are?performing.? ? Head?Carriage? ? Reins?are?used?to?modify?head?placement?during?locomotion;?and?in?turn,? has?a?direct?impact?on?limb?activity?(Biau?et?al.?2002?).??Roepstorff?et?al.?(2002)? determined? that? forelimb? activity? was? influenced? significantly? more? than? hindlimb?activity?with?rein?adjustment.??Specifically,?when?using?draw?reins?to? lower? headset? and? increase? collection,? horses? performed? the? trot? with? longer? forelimb? (87.25? ?? 3.25? ms)? than? hindlimb? (78.93? ?? 3.21? ms)? stance? durations? (Roepstorff? et? al.? 2002).??A? low? headset,? characteristic? of? stock? breed? western? pleasure?horses,?may?have?similar?effects?to?those?of?draw?reins?on?gait?since?the? jog?exhibited?a?longer?forelimb?stance?(626???40?ms)?duration?than?hindlimb?(559? ??47?ms)?stance?duration?(Booker?2005).??Although?no?scientific?literature?exists? that?links?the?stock?breed?western?pleasure?horse?to?a?shift?in?weight,?stock?breed? 59 western? pleasure? horses? at? the? jog? have? been? found? to? spend? a? considerable? amount?of?time?in?fore?stance?(626???40?ms)?when?compared?to?the?hind?(559???47? ms)?and?implies?a?greater?amount?of?weight?being?carried?on?the?forelimbs,?or? forehand? (Booker? 2005).??Increased? weight? on? the? forelimbs? would? result? in? a? heavier? gait? than? is? acceptable? according? to? stock? breed? western? pleasure? standards? and? may? be? linked? to? the? injuries? seen? in? the? forelimbs? of? western? pleasure?horses.??Contrastingly,?head?and?neck?positions?that?have?been?found?to? induce? a? weight? shift? from? the? forehand? to? the? hindquarters? in? unridden? dressage? horses? at? the? walk? and? trot? include? positions? where:? (a)? the? neck? is? moderately?elevated?and?the?poll?is?flexed?or?extended?slightly?and?(b)?a?low,? flexed?head?and?neck?with?the?poll?extremely?flexed?behind?vertical?(Waldern?et? al.?2009).??At?first?glance?these?findings?seem?counterintuitive?since?it?has?been? hypothesized? that? the? increased? forelimb? stance? seen? in? stock? breed? western? pleasure?horses?when?compared?to?hindlimb?stance?is?due?to?the?horse?s?head?set;? however,? a? dressage? horse?s? ?low?? headset? is? going?to?be?higher?than?a?stock? breed?western?pleasure?horse?s??normal??headset.??Further?studies?by?Rhodin?et? al.?(2005)?used?side?reins?to?determine?head?and?neck?positions,?range?of?motion? for?flexion?extension,?lateral?bending,?and?axial?rotation?of?the?back?during?the? walk?and?trot.? 60 Rhodin?et?al.?(2005)?evaluated?back?kinematics?at?the?walk?and?trot?using? side?reins?and?determined?that?horses?that?were?forced?to?work?in?a?low?headset,? like?the?stock?breed?western?pleasure?horse,?had?decreased?lateral?bending?in?the? lumbar?region?and?decreased?flexion?extension?of?the?back?when?compared?to?a? free?position.??Decreased?back?movement?is?evident?in?the?minimal?vertical?ROM? for?the?withers?(9.06???2.84?cm),?loin?(9.10???2.41?cm),?and?croup?(8.97???2.63?cm)?of? the?stock?breed?western?pleasure?horse?(Booker?2005);?however,?the?headset?of? horses?in?the?Rhodin?et?al.?(2005)?study?had?the?head?and?neck?fixed?in?the?low? position,?while?stock?breed?western?pleasure?horses?naturally?carry?their?head?in? a?low?position?without?restraint.??Decreased?back?movements?seen?in?stock?breed? western?pleasure?horses?may?be?a?direct?result?of?this?collected?frame?required?to? execute? the? jog? and? lope? correctly,? according? to? stock? breed? association? guidelines.??The?collected?frame?is?a?result?of?restriction?by?the?horse?of?vertical? displacement?of?the?head,?spine,?and?hip.??It?is?possible?that?the?collected?frame?of? the? stock? breed? western? pleasure? horse? also? has? implications? to? balance.??As? horses?begin?traveling?at?slower?velocities,?as?seen?in?the?walking?half?pirouette? and?passage?of?dressage?horses?(Clayton?1989;?Hodson?et?al.?1999)?and?western? pleasure?jog?and?lope?(Nicodemus?2007;?Nicodemus?and?Booker?2007),?there?is?a? loss? of? forward? motion? that? causes? the? horse? to? become? unbalanced.??This? unbalanced?posture?results?in?a?loss?of?dynamic?stability?and?has?been?linked?to? 61 the?presence?of?quadrupedal?support?during?gaits?with?slow?velocities?(Clayton? 1989;? Hodson? et? al.? 1999;? Nicodemus? and? Booker? 2007).??Ultimately,? judging? standards?that?allow?for?a?less?collected?frame?and?higher?headset?in?stock?breed? western?pleasure?horses?may?produce?differences?in?gait.? ? Injuries? ? Modern?stock?breed?western?pleasure?horses?are?being?bred?specifically? for?western?pleasure?competition?and?thus?have?a?different?body?type?than?other? stock? horses,? which? may? predispose? them? to? skeletal? injuries.??This? modern? western?pleasure?horse?is?taller?and?has?less?muscle?mass?over?the?shoulders?and? hindquarters? with? steeper? shoulder? (scapular)? and? pastern? (proximal? phalanx,? P1)?angles?than?typical?stock?horses?(Figure?1.4)?(Black?1999).??Western?pleasure? horses?tend?to?be?shod?at?steep?hoof?angles?with?aluminum?shoes,?which?further? increases?hoof?angle?and?decreases?breakover?time?for?carpus?flexion?to?allow?for? the??flat?kneed??appearance?of?the?stock?breed?western?pleasure?horse.??Stock? breed?horses?also?have?a?smaller?foot?size,?when?compared?to?body?size,?which? increases?the?propensity?for?hoof?lameness?including?inflammation?of?the?distal? coffin? (interphalangeal)? joint,? which? is? the? articulation?of?the?distal?end?of?the? middle?phalanx,?proximal?end?of?distal?phalanx,?and?the?distal?sesamoid?bone? and?may?have?implications?for?balance.?Other?injury?locations?that?are?common? 62 due? to? the? combination? of? conformational? aspects,? fatigue,? early? training,? and? shoeing?techniques?are?the?proximal?origin?of?the?suspensory?ligament?as?well?as? the?pastern?(proximal?interphalangeal)?joint?and?hock?(tarsus)?of?the?hindlimb? (Figure? 1.4).??Back? soreness? due? to? inflammation? of? the? hock? or? pastern? joint,? inexperienced? or? overweight? riders,? and? improper? saddle? fit? are? also? major? contributors? to? injuries? in? stock? breed? western? pleasure? horses;? however,? osteoarthritis?due?to?trauma?is?the?most?common?cause?of?stifle?(femoropatellar? and? femorotibial)? joint? lameness? in? the? stock? breed? western? pleasure? horse? (Noble?2001).??? Osteoarthritis? or? degenerative? joint? disease? (DJD)? makes? up? 33%? of? all? equine?lameness?and?is?the?inflammation?of?moveable?weight?bearing?joints?due? to? the? degeneration? of? articular? cartilage? and? the? subsequent? exposure? and? formation?of?subchondral?bone?in?the?weak?areas?(Alwan?et?al.?1991;?Clyne?1987).?? Primary? causes? of? DJD? include? normal? wear? and? tear,? ageing,? or? heredity;? secondary? causes? include? trauma,? joint? overload? and? instability,? acute? inflammatory?joint?disease,?infection,?or?other?bone?disease.??Young?horses?are? susceptible? to? DJD? in? highly? moveable? joints? such? as? the? carpus? and? fetlock? (metacarpophalangeal)?joints?(Figure?1.4)?while?older?horses?are?more?susceptible? to?injury?at?the?hock?(intertarsal?and?interphalangeal)?joint?(Auer?and?Fackelman? 1981;?Clyne?1987).??Some?predispositions?to?developing?DJD?are?fatigue,?chronic? 63 joint?overuse,?early?training,?conformation?defects,?and?shoeing?techniques;?stock? breed?western?pleasure?horses?fall?into?each?predisposition?category?(Auer?and? Fackelman?1981).??? ? While? no? scientific? literature? exists? directly? linking? western? pleasure? to? osteoarthritis,?it?is?accepted?in?the?equine?industry?that?elite?performance?horses? that?have?been?showing?at?the?national?level?since?the?age?of?two?do?not?often? maintain? a? show? career? after? the? age? of? five.??This? lack? of? senior? aged? performance?horses?is?anecdotally?linked?to?osteoarthritis?induced?by?the?intense? training?these?horses?receive?early?in?the?show?career?and?the?ultra?slow?gait?they? are? expected? to? achieve.??This? investigation? will? lead? to? insight? in? the? performance? of? these? gaits? and? help? determine? whether? the? high? level? of? collection?required?to?perform?the?jog?and?lope,?coupled?with?the?speed?of?the? gait,?increases?the?horse?s?risk?for?joint?injury?and?trauma.??? ? Summary? ? ? In? light? of? the? limited? previous? scientific? work? evaluating? stock? breed? western?pleasure?horses?the?need?for?further?research?is?evident.??The?jog?and? lope? of? the? stock? breed? western? pleasure? horse? are? highly? specialized? gaits? performed?by?an?elite?sector?of?the?equine?industry.??Identifying,?defining,?and? contrasting?the?collected?and?extended?jog?and?lope?as?well?as?evaluating?the?role? 64 of?head?position?may?have?implications?for?mechanisms?of?injury?in?stock?breed? western?pleasure?horses.??There?are?apparent?contradictions?in?classification?of? the?jog?and?lope?by?the?industry?as?well?as?breed?association?definitions.??The? equine?industry?views?the?stock?breed?western?pleasure?jog?and?lope?as?collected? versions?of?the?dressage?horse?trot?and?canter,?respectively.??Based?on?kinematic? evidence,? this? classification? is? accurate;? however,? when? compared? to? temporal? variables,?the?jog?and?lope?are?not?just?slower?more?collected?versions?of?the?trot? and?canter;?the?trot?and?canter?are?classified?as?leaping?gaits?while?the?jog?and? lope? are? stepping? gaits.??Further,? the? breed? association? definitions? imply? suspension?in?these?gaits?because?the?jog?should?be?a?two?beat?gait?and?the?lope? should?be?a?three?beat?gait.??In?order?to?perform?the?jog?and?lope?correctly,?the? gaits?would?have?to?exhibit?a?period?of?suspension?between?each?beat?of?the?trot? and?after?the?third?beat?of?the?lope.?The?extended?jog?and?lope?of?the?stock?breed? western? pleasure? horse? have? not? been? previously? evaluated? and? may? more? closely? follow? the? breed? association? definitions? for? performance? and? head? position.??Additionally,? the? performance? of? the? extended? jog? and? lope? should? conform?to?a?more?natural?way?of?going?for?the?horse,?have?more?forward?motion? and?range?of?motion,?thereby?reducing?the?risk?of?joint?injury.? 65 Chapter?III? ? Materials?and?Methods? ? ? ? The? purpose? of? this? study? was? to? collect? temporal,? linear,? and? angular? kinematics?for?each?gait?of?the?stock?breed?western?pleasure?horse?in?order?to? compare?the?variables?of?the?collected?and?extended?jog?and?the?collected?and? extended? lope? as? well? as? head? position? to? determine? consistency? with? current? rulebooks?of?major?stock?breed?associations.??Additionally,?this?study?sought?to? determine?if?the?extended?jog?and?lope?conform?to?a?more?natural?way?of?going? for?stock?breed?western?pleasure?horses,?which?may?reduce?the?risk?of?joint?injury? and?trauma?than?does?the?collected?jog?and?lope.??The?current?chapter?presents? the? materials? and? methods? and? includes? sections? a)? animals,? b)? recording? techniques,?c)?data?collection,?d)?data?analysis,?and?e)?statistics.? ? ? ? ? 66 Animals? ? Six? stock? breed? western? pleasure? horses,? four? geldings? and? two? mares,? (5.50???1.87?years;?1.54???0.02?m;?417.98???20.13?kg)?were?used?for?this?study?based? on? the? horse?s? current? status? as? a? western? pleasure? horse? in? training? or? competition?(Table?3.1).??Three?strides?from?each?horse?for?each?gait,?collected? and?extended?jog?and?lope?(right?and?left?leads),?were?analyzed.??Horses?selected? for?this?study?1)?were?located?at?a?nationally?known?stock?breed?western?pleasure? trainer?s? facility,? 2)? demonstrated? desirable? jogging? and? loping? qualities? according? to? what? is? currently? being? seen? in? stock? breed? western? pleasure? competition,? 3)? determined? to? be? ?healthy?? for? the? purpose? of? this? research? project?on?data?collection?day?by?a?licensed?veterinarian,?4)?are?actively?training? for? or? competing? in? stock? breed? western? pleasure? competition,? and? 5)? demonstrated?visual?soundness.??The?research?team?included?individuals?who? are? actively? involved? in? the? equine? industry? and? are? qualified? to? render? judgments? concerning? gait? quality? and? acceptability? in? stock? breed? western? pleasure?as?well?as?soundness.??To?insure?consistency,?the?same?person?affixed? the?markers?on?the?horses,?and?the?same?rider?rode?all?horses.?? An? owner/agent? consent? form? was? signed? for? each? equine? subject? (Appendix?A.1),?and?information?regarding?age,?breed,?sex,?show?history,?height,? 67 and? weight? was? gathered? and? documented? by? the? research? team? before? each? horse?was?analyzed?(Table?3.1,?Appendix?A.2).??Weight?was?estimated?prior?to? videotaping?using?a?commercially?available?standard?equine?measure?tape?while? height?was?determined?using?a?standard?equine?height?stick;?the?same?researcher? recorded? each? measurement.??All? horses? wore? aluminum? wedge? shoes? on? the? fore? hooves;? four? of? the? six? horses? wore? light? steel? racing? plates? on? the? hind? hooves? while? the? remaining? two? did? not? wear? hind? shoes? at? all.??No? intra? articular?joint?injections?of?any?kind?were?noted?for?the?stifle,?hock,?fetlock,?or? coffin?joints?within?the?last?year.??? ? Table? 3.1:??Subject? information? and? means? (?? s.d.)? on? research? animals? including?randomly?assigned?horse?number,?age?(years),?gender?(M?=?mare,?G? =?gelding),?height?(meters),?weight?(kilograms),?and?breed?registry?(AQHA?=? American? Quarter? Horse? Association,? PHBA? =? Palomino? Horse? Breeders? Association;?APHA?=?American?Paint?Horse?Association).??? Horse?#? Age? (yrs)? Gender? (M/G)? Height? (m)? Weight?? (kg)? Breed? Registry? 1? 5? M? 1.53? 441.80? AQHA? 2? 4? G? 1.54? 428.64? AQHA? 3? 8? G? 1.53? 396.43? AQHA/P HBA? 4? 6? G? 1.51? 390.54? APHA? 5? 7? M? 1.57? 428.64? APHA/P HBA? 6? 3? G? 1.57? 421.84? AQHA? Means?? (??s.d.)? 5.50? (1.87)? ? 1.54? (0.02)? 417.98? (20.13)? ? ? 68 Recording?Techniques? ? Flat? retroreflective? markers? comprised? of? Polyken? (Tyco? Adhesives,? Norwood? MA)? and? Johnson? &? Johnson? Athletic? tape? (Johnson? &? Johnson? Services,?New?Brunswick,?NJ)?were?placed?over?seven?points?on?the?lateral?side? of?the?left?and?right?forelimb?following?the?recommendations?of?Back?et?al.?(1995)? and?were?used?to?calculate?angles?between?the?proximal?and?distal?segments?of? the?joints?tracked:??the?proximal?end?of?the?spine?of?the?scapula,?posterior?aspect? of?the?tuberculum?majus?of?the?humerus?(shoulder?joint),?transition?between?the? proximal? and? the? middle? thirds? of? the? lateral? collateral? ligament? (LCL)? of? the? cubital?joint?(elbow?joint),?midway?between?the?site?of?attachment?of?the?LCL?of? the?carpal?joint?and?the?styloid?process?(carpal?joint),?site?of?attachment?of?the? LCL?of?the?metacarpophalangeal?joint?(fore?fetlock?joint),?estimated?center?of?the? rotation?of?the?distal?interphalangeal?joint?(coffin?joint),?and?proximal?aspect?of? the?lateral?hoof?wall?(fore?hoof)?(Figures?3.1????3.3).?Seven?markers?of?the?same? materials? were? placed? on? the? lateral? side? of? the? left? and? right? hindlimb:??the? ventral?aspect?of?the?tuber?coxae?(point?of?the?hip),?lateral?aspect?of?the?greater? trochanter?(hip?joint),?lateral?condyle?of?the?femur?(stifle?joint),?talus?(hock?joint),? metatarsal?attachment?of?the?LCL?of?the?metacarpophalangeal?joint?(hind?fetlock? joint),? over? the? estimated? center? of? rotation? of? the? distal? interphalangeal? joint? (coffin?joint),?and?proximal?aspect?of?the?lateral?hoof?wall?(hind?hoof)?(Figures?3.1? 69 ?? 3.3)? (Back? et? al.? 1995).??Additional? markers? tracked? the? medial? aspect? of? the? coffin?bone?on?the?right?and?left?fore?and?hindlimbs?(Figure?3.1?&?3.2).??A?marker? was?placed?on?the?right?and?left?side?of?the?temporal?bone,?along?the?zygomatic? process?to?determine?head?position?(Figure?3.1?&?3.2).??Markers?comprised?of?one? half?of?a?styrofoam?ball?covered?with?Scotchlite?8850?retroreflective?tape?(Motion? Lab? Systems,? Inc.,? Baton? Rouge,? LA)? and? mounted? on? black? foam? were? used? along?the?vertebral?column?at?the?withers,?lumbar?sacral?junction,?and?point?of? the?croup?(Figure?3.3).?? Figure?3.1:??Retroreflective?marker?locations?for?data?collection.??Marker? placement?was?the?same?for?each?side?of?the?horse.??? 70 Figure? 3.2:? Horse? 1? during? data? collection? demonstrating? placement? of? the? reflective? markers? on? the? lateral? side?fore?and?hindlimbs,?along?the?vertebral? column,? and? at? the? zygomatic? process.??Flat? retroreflective? markers? were? comprised?of?polyken?(Tyco?Adhesives,?Norwood?MA)?and?Johnson?&?Johnson? Athletic?tape?(Johnson?&?Johnson?Services,?New?Brunswick,?NJ).? Figure?3.3:??Three?dimensional?markers?comprised?of?one?half?of?a?styrofoam? ball?covered?with?Scotchlite?8850?retroreflective?tape?(Motion?Lab?Systems,?Inc.,? Baton?Rouge,?LA)?and?mounted?on?black?foam?were?used?along?the?vertebral? column?at?the?withers,?lumbar?sacral?junction,?and?point?of?the?croup.? 71 Data?Collection? ? In?order?to?obtain?video?footage?of?each?horse?performing?at?an?optimal? level,?the?same?rider?who?trains?the?horse?rode?each?horse?at?the?collected?and? extended?jog?and?lope?through?the?capture?volume.??All?equine?subjects?wore?the? same?saddle?and?saddle?pad?(20.41?kg)?as?well?as?bridle?and?correction?bit?(1.36? kg)?during?data?collection.??The?capture?volume?was?created?using?four?orange? cones?set?in?a?3.05?m?x?3.35?m?rectangle?(Figure?3.4).??Horses?were?videotaped? using? two? 30? Hz? Canon? 3CCD? digital? video? camcorders? (GL2? NTSC,? Canon,? Lake?Success,?New?York,?USA).??Camcorders?were?set?perpendicular?to?the?plane? of?motion?at?7.16?m?from?the?edge?of?the?capture?volume?to?the?center?of?the? tripod,?one?on?either?side?of?the?horse?(Figure?3.4).??Cameras?were?set?to?capture? two?full?strides?at?a?height?of?1.37?m,?and?videotaped?the?horses?performing?the? collected? and? extended? jog? and?lope?through?the?capture?volume?(Figure?3.4).?? The?capture?volume?was?calibrated?using?a?1?m?x?1?m?calibration?frame?that?was? placed?in?the?center?of?the?capture?volume?before?each?trial.??The?runway?(5?cm? deep? when? packed? and? 6? cm? deep? when? unpacked)? was? raked? and? packed? between?each?trial?to?ensure?noticeable?hoof?placement?and?lift?off.??For?each?gait? considered,? horses? were? allowed? a? practice? trial? to? acclimate? the? horse? to? the? capture?volume.??A?successful?trial?was?determined?visually?by?the?research?team? and? required? consistency? of? the? collected? and? extended? jog? and? lope? using? 72 3.05?m 3.35?m 3.35?m 3.05?m Camera?1? 7.16?m? Camera?2? 7.16?m? noticeable? hoof? contact? and? lift?off,? correctness? of? gait,? and? sustained? marker? attachment.??Three?successful?trials?of?the?collected?and?extended?jog?and?lope? were?captured?for?each?horse.??? ? Figure?3.4:??Depiction?of?the?capture?volume?with?orange?cones?set?at?a?3.05?m?x? 3.35?m?rectangle,?and?cameras?set?7.16?m?from?the?edge?of?the?capture?volume?for? data?collection?of?the?collected?and?extended?jog?and?lope?of?stock?breed?western? pleasure? horses.??Center? arrow? indicates? direction? of? travel;? drawing? is? not?to? scale.? ? ? Data?Analysis? ? Three?successful?strides?of?the?collected?(n?=?18)?and?extended?(n?=?18)?jog? and?the?collected?lope?right?lead?(n?=?18)?and?left?lead?(n?=?18)?and?extended?lope? right?lead?(n?=?18)?and?left?lead?(n?=?18)?were?analyzed?using?the?Peak?Motus ? ? 1994?2004? motion? analysis? system? (Peak? Performance? Technologies,? Inc.,? Englewood,? Colorado,? USA).??Digitization,? transformation,? smoothing,? and? 73 normalization? techniques? followed? standard? kinematic? techniques? when? using? the?Peak?Motus?system?(Schamhardt?et?al.?1993).??? Temporal? variables? were? visually? determined? for? all? strides? of? the? collected? and? extended? jog? and? lope? using? frame?by?frame? analysis? of? video? frames?to?document?hoof?placement?and?lift?off?for?calculation?of?stride?duration,? fore? and? hindlimb? stance? and? swing? durations,? diagonal? advanced? placement? and? lift?off,? lateral? advanced? placement? and? lift?off,? and? limb? support? phases.?? The?gait?cycle?was?considered?to?be?hind?hoof?contact?to?the?next?contact?of?the? ipsilateral?hind?hoof.??Hoof?placement?was?determined?to?take?place?during?the? frame?where?any?part?of?the?hoof?visually?made?contact?with?the?ground,?and?lift? off?was?documented?as?the?frame?where?all?parts?of?the?hoof?were?visually?not?in? contact?with?the?ground.??Stride?duration?was?calculated?as?the?time?it?takes?to? make? one? full? stride? cycle? and? was? measured? in? seconds? (s).??Forelimb? and? hindlimb? stance? was? determined? as? the? time? from? hoof? placement? to? lift?off.?? Diagonal?advanced?placement?was?calculated?as?the?time?between?placement?of? the? forelimb? and? the? placement? of? the? diagonal? hindlimb;? whereas,? lateral? advanced? placement? was? calculated? as? the? time? between? placement? of? the? hindlimb?and?the?placement?of?the?lateral?forelimb.??Diagonal?advanced?lift?off? was? determined? as? the? time? between? lift?off? of? the? forelimb? and? diagonal? hindlimb.??Lateral?advanced?lift?off?was?determined?as?the?time?between?lift?off? 74 of?the?hindlimb?and?lateral?forelimb.?The?number?of?limbs?supporting?the?body? sequentially? through? the? stride? determined? limb? support? sequence? (Clayton? 2004).??? The? shoulder? joint? was? calculated? using? the? markers? at? spine? of? the? scapula,?shoulder,?and?elbow,?and?the?elbow?joint?was?calculated?using?markers? at?the?shoulder,?elbow,?and?carpus?(Figure?3.5).??Markers?at?the?elbow,?carpus,? and?fetlock?were?used?to?calculate?the?carpal?joint?while?the?fore?fetlock?joint?was? calculated?using?the?markers?at?the?carpus,?fore?fetlock,?and?fore?coffin?(Figure? 3.5).??The?hip?joint?was?calculated?using?the?markers?at?the?point?of?the?hip,?hip,? and?stifle,?and?the?stifle?joint?was?calculated?using?the?markers?at?the?hip,?stifle,? and?hock?(Figure?3.6).??Markers?at?the?stifle,?hock,?and?hind?fetlock?were?used?to? calculate?the?hock?joint?while?the?markers?at?hock,?fetlock,?and?hind?coffin?were? used?to?calculate?the?hind?fetlock?joint?(Figure?3.6).? Graphical? depictions? of? the? joint? motion? were? used? to? create? models? of? limb?coordination.??Joint?angles?were?measured?on?the?flexor?side?of?the?joint?and? upward?curves?indicate?flexion?while?downward?curves?indicate?extension?of?the? joint.??Displacements?of?the?limbs,?spine,?and?head?were?tracked?with?horizontal? displacement? taken? from? the? most? caudal? to? the? most? cranial? location? of? the? tracked?marker.??Vertical?displacement?was?taken?from?the?most?proximal?to?the? most?distal?location?of?the?tracked?marker.??? 75 Fore?Hoof Fore?Coffin?Joint Fore?Fetlock?Joint? Carpal?Joint? Elbow?Joint?? Shoulder?Joint? Spine?of?the?Scapula Hind?Hoof Hind?Coffin?Joint? Hind?Fetlock?Joint? Hock?Joint Stifle?Joint? Hip?Joint? Point?of?the?Hip ? ? Figure?3.5:??Depiction?of?forelimb?joint?angles?for?calculation?of?joint?kinematics? of?the?stock?breed?western?pleasure?horse:??the?proximal?end?of?the?spine?of?the? scapula,?shoulder?joint,?elbow?joint,?carpal?joint,?forelimb?fetlock?joint,?forelimb? coffin?joint,?and?lateral?fore?hoof.? ? ? ? ? ? ? ? Figure?3.6:??Depiction?of?hindlimb?joint?angles?for?calculation?of?joint?kinematics? of?the?stock?breed?western?pleasure?horse:??point?of?the?hip,?hip?joint,?stifle?joint,? hock?joint,?hindlimb?fetlock?joint,?hindlimb?coffin?joint,?and?lateral?hind?hoof.? ? 76 Statistics? Means? and? standard? deviations? of? the? temporal,? linear,? and? angular? kinematic?variables?of?the?jog?(collected?and?extended)?and?lope?(collected?and? extended)? were? calculated.??A? paired?samples? T? test? was? used? to? determine? symmetry?of?the?collected?and?extended?jog?by?comparing?the?stance?and?swing? durations? of? the? right? and? left? fore? and? hindlimbs.??Since? gait? symmetry? was? determined,?the?left?and?right?variables?of?the?collected?and?extended?jog?were? collapsed.??Paired?samples?T?test?were?used?to?compare?the?collapsed?variables?of? fore?to?hindlimb?stance?and?swing?durations,?diagonal?advanced?placement?to? lateral? advanced? placement,? as? well? as? diagonal? advanced? lift?off? to? lateral? advanced?lift?off?to?assist?in?defining?the?collected?and?extended?jog.???Vertical? excursions?of?the?head,?withers,?and?hip?were?examined?via?paired?samples?T? tests? to? determine? topline? variability? within? the? collected? and? extended? jog.?? Temporal?variables?of?the?collected?and?extended?jog?were?differentiated?using?a? multivariate? repeated? measures? ANOVA? to? examine? stride? duration;? diagonal? and?lateral?advanced?placements?and?lift?offs;?and?bipedal,?quadrupedal,?tripedal? with?two?fore,?and?tripedal?with?two?hindlimb?support.??Linear?variables?of?the? collected? and? extended? jog? were? differentiated? using? a? multivariate? repeated? measures?ANOVA?to?examine?stride?length,?velocity,?and?vertical?excursions?for? the? head,? withers,? hip,? and? fore? and? hind? coffin.??One? multivariate? repeated? 77 measures? ANOVA? was? conducted? to? determine? the? angular? kinematic? differences?between?the?collected?and?extended?jog?for?the?shoulder,?carpus,?hip,? stifle,?and?hock?joint?angles.??? A?paired?samples?T?test?was?used?to?determine?asymmetry?of?the?collected? and?extended?lope?by?comparing?the?stance?and?swing?durations?of?the?right?and? left? fore? and? hindlimbs.??Paired?samples? T? test? were? used? to? compare? fore? to? hindlimb? stance? and? swing? durations,? diagonal? advanced? placement? to? lateral? advanced? placement,? as? well? as? diagonal? advanced? lift?off? to?lateral?advanced? lift?off?to?assist?in?defining?the?collected?and?extended?lope.???Vertical?excursions? of? the? head,? withers,? and? hip? were? examined? via? paired?samples? T? tests? to? determine?topline?variability?within?the?collected?and?extended?lope.??Temporal? variables? of? the? collected? and? extended? lope? were? differentiated? using? a? multivariate? repeated? measures? ANOVA? to? examine? stride? duration;? diagonal? and? lateral? advanced? placements? and? lift?offs;? and? bipedal,? tripedal? with? two? fore,?tripedal?with?two?hindlimb,?and?unipedal?support.??Linear?variables?of?the? collected? and? extended? lope? were? differentiated? using? a? multivariate? repeated? measures?ANOVA?to?examine?stride?length,?velocity,?and?vertical?excursions?for? the? head,? withers,? hip,? and? fore? and? hind? coffin.??Two? multivariate? repeated? measures? ANOVAs? were? conducted? to? determine? the? angular? kinematic? differences?between?the?collected?and?extended?lope,?one?for?leading?limbs?and? 78 one? for? trailing? limbs.??For? the? forelimb,? shoulder? and? carpus? angles? were? evaluated,?and?for?the?hindlimb,?hip,?stifle,?and?hock?angles?were?evaluated.??? Due? to? the? large?number?of?variables?analyzed?and?the?relatively?small? sample? size,? there? were? insufficient? residual? degrees? of? freedom? to? perform? a? multivariate? ANOVA? for? the? temporal,? linear,? or? angular? variables? of? the? collected? and? extended? jog? and? lope.??Therefore,? the? univariate? results? are? presented? cautiously? and? with? the? understanding? of? the? risk? of? type? 1? errors? being? increased? due? to? the? number? of? comparisons? being? performed.??A? significance?level?of?95%?was?chosen?for?statistical?comparisons,?all?variables?that? were? deemed? significant? had? a? univariate? P? value? less? than? or? equal? to? 0.04.?? Therefore,?the?risk?of?type?1?errors?is?rather?small,?even?considering?the?number? of?comparisons?being?performed.??All?statistical?procedures?were?calculated?by? PASW?software?(Version?18.0;?SPSS?Inc.,?Chicago,?Illinois,?USA),?and?statistical? significance?will?be?determined?by?a?P?value?less?than?0.05?(P?0.05).? 79 Chapter?IV? ? Results? ? ? ? The? purpose? of? this? study? was? to? collect? temporal,? linear,? and? angular? kinematics?for?each?gait?of?the?stock?breed?western?pleasure?horse?in?order?to? compare?the?variables?of?the?collected?and?extended?jog?and?the?collected?and? extended? lope? as? well? as? head? position? to? determine? consistency? with? current? rulebooks?of?major?stock?breed?associations.??Additionally,?this?study?sought?to? determine?if?the?extended?jog?and?lope?conform?to?a?more?natural?way?of?going? for?stock?breed?western?pleasure?horses,?which?may?reduce?the?risk?of?joint?injury? and?trauma?than?does?the?collected?jog?and?lope.??The?current?chapter?presents? the? results? and? includes? sections? a)? collected? jog,? b)? extended? jog,? c)? collected? versus?extended?jog,?d)?collected?lope,?e)?extended?lope,?and?f)?collected?versus? extended?lope.? 80 Collected?Jog? ? Temporal?and?linear?kinematics.? ? ? In? accordance? with? past? stock? breed? western? pleasure? research? (Nicodemus?and?Booker?2007;?Nicodemus?and?Clayton?2003),?the?collected?jog? (n=6)? in? the? present? study? had? a? lateral? footfall? sequence? due? to? hind? limb? touchdown?followed?by?the?touchdown?of?the?front?limb?on?the?ipsilateral?side? (Figure?4.1).??Horses?performed?the?collected?jog?with?a?mean?stride?length?of?1.28? ??0.17?m,?duration?of?1.91???0.12?s,?and?frequency?of?0.53???0.03?stride/s.??Velocity? of?the?collected?jog?was?0.67???0.01?m/s.??Hind?step?length?was?0.55????0.20?m?and? fore?step?length?was?0.58???0.10?m,?each?consisting?of?approximately?one?half?of? the? total? stride? length.??Consistent? with? a? symmetrical? gait,? no? statistical? significance? was? found? between? the? stance? or? swing? durations? of? the? left? and? right? fore? (stance? P=0.41;? swing? P=0.22)? or? left? and? right? hind? (stance? P=0.41;? swing? P=0.50)? limbs? (Table? 4.2? &? 4.3).??Since? the? gait? is? determined? to? be? symmetrical,?temporal?variables?were?collapsed?for?the?left?and?right?variables.?? A?significant?difference?was?found?between?the?collapsed?variables?for?fore?and? hind?limb?stance?(P?0.05)?and?swing?(P?0.05)?durations?(Table?4.2).? ? ? 81 LH LF RH RF 1 LH LF RH RF 4 LH LF RH RF 2 LH LF RH RF 3 Figure?4.1:?Lateral?footfall?sequence?of?the?collected?jog?as?performed?by?the? stock?breed?western?pleasure?horse.??Each?circle?is?representative?of?a?horse?s? hoof?(LH???left?hind,?LF???left?fore,?RH???right?hind,?RF???right?fore).??? ? ? ? Table?4.1:??Means?(??s.d.)?for?stance?durations?(s)?for?the?following?limbs?of?each? stock?breed?western?pleasure?horse?(Subject?1?6)?at?the?collected?jog:?right?hind? (RH),?left?hind?(LH),?right?fore?(RF),?and?left?fore?(LF).??? Subject? RH?(s) ? LH?(s) ? RF?(s) ? LF?(s) ? 1? 1.12?(0.02) a 1.10?(0.03) a ? 1.17?(0.06) b 1.18?(0.05) b 2? 1.29?(0.04) a 1.31?(0.11) a ? 1.28?(0.02) b 1.27?(0.07) b 3? 1.22?(0.05) a 1.20?(0.09) a ? 1.34?(0.17) b 1.49?(0.20) b 4? 1.17?(0.03) a 1.19?(0.02) a ? 1.42?(0.05) b 1.38?(0.05) b 5? 1.22?(0.04) a 1.24?(0.07) a ? 1.30?(0.09) b 1.34?(0.14) b 6? 1.11?(0.15) a 0.78?(0.50) a ? 1.22?(0.12) b 1.22?(0.04) b 1.18?(0.07) a? 1.14??(0.19) a? 1.29?(0.09) b? 1.31?(0.11) b? Mean?(??s.d.)? 1.16?(0.12) a? 1.30?(0.20) b ? Means? within? the? same? row? followed? by? different? letters? are? significantly? different?at?P?0.05.??? ? ? 82 Table?4.2:??Means?(??s.d.)?for?swing?durations?(s)?for?the?following?limbs?of?each? stock?breed?western?pleasure?horse?(Subject?1?6)?at?the?collected?jog:?right?hind? (RH),?left?hind?(LH),?right?fore?(RF),?and?left?fore?(LF).??? Subject? RH?(s) ? LH?(s) ? RF?(s) ? LF?(s) ? 1? 0.59?(0.02) a 0.59?(0.07) a 0.52?(0.02) b 0.54?(0.04) b 2? 0.65?(0.02) a 0.63?(0.03) a 0.64?(0.02) b 0.61?(0.04) b 3? 0.68?(0.05) a 0.70?(0.03) a 0.64?(0.05) b 0.64?(0.05) b 4? 0.90?(0.06) a 0.84?(0.04) a 0.63?(0.00) b 0.67?(0.03) b 5? 0.74?(0.04) a 0.72?(0.02) a 0.65?(0.05) b 0.69?(0.05) b 6? 0.74?(0.07) a 1.10?(0.58) a 0.63?(0.00) b 0.68?(0.07) b 0.72?(0.11) a? 0.76?(0.19) a? 0.62?(0.10) b? 0.64?(0.10) b? Mean?(??s.d.)? 0.74?(0.13) a? 0.63?(0.05) b? Means? (?? s.d.)? within? the? same? row? followed? by? different? letters? are? significantly?different?at?P?0.05.??? ? ? Lateral? advanced? placement? was? 0.88? ?? 0.14? s? and? showed? statistical? significance?(P?0.05)?from?diagonal?advanced?placement,?0.13???0.05?s.??Lateral? advanced?lift?off?(0.90???0.12?s)?and?diagonal?advanced?lift?off?(0.09???0.05?s)?also? showed? statistical? significance? (P?0.05).??Advanced? placements? and? lift?offs? indicate?that?footfalls?of?the?collected?jog?occurred?as?diagonal?couplets,?instead? of?diagonal?pairs?that?are?dictated?by?the?breed?standard,?so?the?gait?had?a?four? beat? rhythm? instead? of? a? two? beat? rhythm.??Only? 16.67%? of? strides? showed? a? diagonal? pair? during? hoof? placement? and? 16.67%? during? lift?off.??The? longest? limb? support? phase? during? the? collected? jog? was? diagonal? bipedal? (57.78? ?? 10.48%)?followed?by?quadrupedal?(19.26???4.35%),?tripedal?with?two?forelimbs? (16.72???12.71%),?and?tripedal?with?two?hindlimbs?(6.24???7.28%)?(Figure?4.2).??As? expected,?there?was?no?period?of?suspension?found?in?the?collected?jog.??? 83 LH LF RH RF 1 LH LF RH RF 4 LH LF RH RF 2 LH LF RH RF 3 LH LF RH RF 5 LH LF RH RF 7 LH LF RH RF 8 LH LF RH RF 6 ? ? ? ? ? ? ? ? Figure?4.2:?Limb?support?phases?of?the?stock?breed?western?pleasure?collected? jog.??Each?circle?is?representative?of?a?horse?s?hoof?(LH???left?hind,?LF???left?fore,? RH???right?hind,?RF???right?fore).??Filled?circles?represent?stance?phase?while? open?circles?represent?swing?phase.??? ? ? Vertical?excursion?was?greatest?for?the?head?(0.12???0.05?m)?followed?by? the?hind?coffin?(0.11???0.01?m),?fore?coffin?(0.09???0.01?m),?croup?(0.08???0.01?m),? and?withers?(0.07???0.01?m)?during?the?collected?jog.??A?statistical?difference?was? not? found? when? comparing? the? vertical? excursions? of? the? withers? to? croup? (P=0.45),?withers?to?head?(P=0.94),?or?croup?to?head?(P=0.18),?which?indicates?that? horses? exhibited? a? balanced? topline? when? performing? the? collected? jog? and,? therefore,?conform?to?breed?standards?concerning?gait?performance.? ? 84 Angular?kinematics.? Peak?flexion?and?extension?as?well?as?joint?range?of?motion?(ROM)?for?the? shoulder,?elbow,?carpus,?fore?fetlock,?hip,?stifle,?hock,?and?hind?fetlock?joints?for? collected?jog?are?shown?in?Table?4.3.??The?greatest?ROM?was?seen?for?the?hind? fetlock?followed?by?the?fore?fetlock,?carpus,?and?elbow?joints;?the?shoulder?joint? exhibited?the?least?ROM.??? Representative?fore?and?hindlimb?joint?kinematics?for? horses? at? the? collected? jog? are? presented? graphically? in? Figures? 4.3? and? 4.4.?? Graphs?were?plotted?from?hoof?contact?to?the?next?contact?of?the?same?hoof?as?a? percent? of? stride? and? represent? joint? flexion? or? extension? during? a? complete? stride.??The?black?vertical?line?indicates?the?initiation?of?stance?phase?for?forelimb? graphs? and? the? initiation? of? swing? phase? for? hindlimb? graphs.??Upward? inclinations? in? graphs? indicate? extension? of? the? joint? while? downward? inclinations?indicate?flexion.??Forelimb?joint?motion?graphs?indicate?that?swing? phase?occurred?from?0???33%?of?the?stride?while?the?shoulder?gradually?extended? and?the?elbow,?carpus,?and?fetlock?gradually?flexed?(Figure?4.3).??Peak?flexion?of? the?carpus?occurred?prior?to?peak?flexion?of?the?elbow?and?fetlock?joints.??Stance? phase?occurred?from?34???100%?of?the?stride?with?the?fore?hoof?making?contact? with?the?ground?at?around?33%?of?stride.??Gradual?extension?of?the?elbow?and? carpus?and?flexion?of?the?shoulder?continued?throughout?stance;?peak?extension? of?the?fetlock?occurred?at?mid?stance.? 85 Hindlimb? joint? motion? graphs? indicate? that? the? first? 61%? of? stride? was? spent? in? stance? phase;? the? hip? gradually? extended? throughout? stance? to? reach? peak?extension?at?late?stance?(Figure?4.4).??The?hock?reached?peak?extension?at? 40%?of?stride?and?then?gradually?flexed?to?reach?peak?flexion?at?mid?swing?phase.?? Swing?phase?occurred?from?62???100%?of?the?stride?while?the?hip,?stifle,?and?hock? gradually?flexed.??Peak?extension?of?the?fetlock?occurred?during?mid?stance,?and? peak?flexion?occurred?during?early?swing?phase.??? ? ? ? ? Table? 4.3:??Means? (? s.d.)? for? peak? flexion? and? extension? joint? angles? (deg)? measured?on?the?flexor?side?of?the?joint?and?range?of?motion?(ROM)?(deg)?for? fore?and?hindlimbs?at?the?collected?jog.? Joint? Peak?Flexion?(deg)? Peak?Extension?(deg)? Joint?ROM?(deg)? Forelimb? Shoulder? 110.04?(7.93)? 118.63?(7.54)? 8.60?(1.77)? Elbow? 93.97?(8.60)? 148.67?(6.78)? 54.70?(4.87)? Carpus? 116.73?(4.75)? 181.63?(2.26)? 64.90?(4.94)? Fetlock? 149.58?(4.34)? 228.18?(8.94)? 78.61?(7.04)? Hindlimb Hip? 100.16?(3.82)? 115.48?(3.46)? 15.32?(1.42)? Stifle? 136.81?(7.93)? 168.81?(6.90)? 32.00?(4.48)? Hock? 133.43?(4.98)? 167.53?(3.85)? 34.10?(4.29)? Fetlock? 145.60?(5.32)? 226.66?(8.02)? 81.06?(8.80)? ? ? ? ? 86 ? ? Collected?Jog?Forelimb?Joint?Motion 80 100 120 140 160 180 200 220 240 260 0% 20% 40% 60% 80% 100% Stride?(%) Angle ? (deg) Shoulder Elbow Carpus Fetlock Figure? 4.3:??Representative? forelimb? motion? graph? of? the? shoulder,? elbow,? carpus,?and?fetlock?joints?(deg)?as?a?percentage?of?stride?(%)?for?one?stride?of? the?collected?jog?of?the?stock?breed?western?pleasure?horse.??The?gait?cycle?was? right?hind?hoof?contact?to?the?next?contact?of?the?right?hind?hoof,?and?the?black? vertical?line?indicates?the?initiation?of?stance?phase.??? ? ? 87 Collected?Jog?Hindlmb?Joint?Motion 80 100 120 140 160 180 200 220 240 260 0% 20% 40% 60% 80% 100% Stride?(%) Angle ? (deg) Hip Stifle Hock Fetlock Figure?4.4:??Representative?hindlimb?motion?graph?of?the?hip,?stifle,?hock,?and? fetlock?joints?(deg)?as?a?percentage?of?stride?(%)?for?one?stride?of?the?collected? jog?of?the?stock?breed?western?pleasure?horse.??The?gait?cycle?was?right?hind? hoof?contact?to?the?next?contact?of?the?right?hind?hoof,?and?the?black?vertical? line?indicates?the?initiation?of?swing?phase.??? ? Extended?Jog? ? Temporal?and?linear?kinematics.? The?extended?jog?(n=6)?had?a?lateral?footfall?sequence?due?to?hind?limb? touchdown?followed?by?the?touchdown?of?the?front?limb?on?the?ipsilateral?side? (Figure?4.1).??Horses?performed?the?extended?jog?with?a?mean?stride?length?of? 1.42? ?? 0.16? m,? duration? of? 1.75? ?? 0.08? s,? and? frequency? of? 0.57? ?? 0.03? stride/s.?? Velocity?of?the?extended?jog?was?0.82???0.01?m/s.??Hind?step?length?was?0.75???? 0.13?m?and?fore?step?length?was?0.65???0.13?m,?with?hind?step?length?not?being? 88 statistically? different? from? fore? step? length? (P=0.28).??Consistent? with? a? symmetrical? gait,? no? statistical? significance? was? found? between? the? stance? or? swing?durations?of?the?left?and?right?fore?(stance???P=0.36;?swing???P=0.52)?or?left? and?right?hind?(stance???P=0.85;?swing???P=0.60)?limbs?(Table?4.4?&?4.5).??Since?the? gait?was?determined?to?be?symmetrical,?temporal?variables?were?collapsed?for?the? left? and? right? variables.??A? significant? difference? was? found? between? the? collapsed? variables? for? fore? and? hind? limb? stance? (P?0.05)? and? swing? (P?0.05)? durations?(Table?4.4?&?4.5).? ? ? Table?4.4:??Means?(??s.d.)?for?stance?durations?(s)?for?the?following?limbs?of?each? stock?breed?western?pleasure?horse?(Subject?1?6)?at?the?extended?jog:?right?hind? (RH),?left?hind?(LH),?right?fore?(RF),?and?left?fore?(LF).??? Subject? RH?(s) ? LH?(s) ? RF?(s) ? LF?(s) ? 1? 1.01?(0.05) a 1.01?(0.04) a ? 1.07?(0.07) b 1.03?(0.00) b 2? 1.11?(0.04) a 1.18?(0.05) a ? 1.11?(0.05) b 1.55?(0.02) b 3? 0.99?(0.05) a 1.03?(0.00) a ? 1.11?(0.04) b 1.07?(0.00) b 4? 1.05?(0.05) a 1.05?(0.07) a ? 1.19?(0.08) b 1.22?(0.10) b 5? 0.98?(0.02) a 0.92?(0.02) a ? 1.08?(0.07) b 1.09?(0.15) b 6? 1.00?(0.00) a 0.97?(0.03) a ? 1.03?(0.00) b 1.08?(0.04) b 1.02?(0.05) a? 1.03??(0.09) a? 1.10?(0.05) b? 1.12?(0.20) b? Mean?(??s.d.)? 1.02?(0.07) a? 1.13?(0.11) b ? Means? (?? s.d.)? within? the? same? row? followed? by? different? letters? are? significantly?different?at?P?0.05.??? ? ? ? ? 89 Table?4.5:??Means?(??s.d.)?for?swing?durations?(s)?for?the?following?limbs?of?each? stock?breed?western?pleasure?horse?(Subject?1?6)?at?the?extended?jog:?right?hind? (RH),?left?hind?(LH),?right?fore?(RF),?and?left?fore?(LF).??? Subject? RH?(s) ? LH?(s) ? RF?(s) ? LF?(s) ? 1? 0.62?(0.02) a 0.61?(0.04) a 0.57?(0.03) b 0.54?(0.02) b 2? 0.64?(0.05) a 0.68?(0.04) a 0.67?(0.06) b 0.69?(0.04) b 3? 0.73?(0.03) a 0.69?(0.02) a 0.64?(0.04) b 0.63?(0.00) b 4? 0.82?(0.04) a 0.83?(0.00) a 0.68?(0.02) b 0.67?(0.03) b 5? 0.75?(0.02) a 0.77?(0.00) a 0.62?(0.02) b 0.69?(0.02) b 6? 0.77?(0.03) a 0.81?(0.05) a 0.69?(0.02) b 0.70?(0.00) b 0.72?(0.08) a? 0.73?(0.09) a? 0.64?(0.05) b? 0.65?(0.06) b? Mean?(??s.d.)? 0.73?(0.08) a? 0.65?(0.05) b? Means?(??s.d.)?within?the?same?row?followed?by?different?letters?are? significantly?different?at?P?0.05.? ? ? Lateral? advanced? placement? was? 0.89? ?? 0.06? s? and? showed? statistical? significance?(P?0.05)?from?diagonal?advanced?placement,?0.06???0.03?s.??Lateral? advanced?lift?off?(0.88???0.05?s)?and?diagonal?advanced?lift?off?(0.07???0.05?s)?also? showed? statistical? significance? (P?0.05).??Advanced? placements? and? lift?offs? indicate?that?footfalls?of?the?extended?jog?occurred?as?diagonal?couplets,?instead? of? diagonal? pairs? as? dictated? by? the? breed? standard.??This? footfall? sequence? yielded? a? gait? with? a? four? beat? rhythm.??Only? 33.33%? of? strides? showed? a? diagonal? pair? during? hoof? placement? and? 33.33%? during? lift?off,? which? again? indicates?that?the?extended?jog?was?not?performed?with?diagonal?pairs?and?does? not?conform?to?the?breed?standard.??The?longest?limb?support?phase?during?the? extended? jog? was? diagonal? bipedal? (70.20? ?? 7.37%)? followed? by? quadrupedal? (14.07???5.47%),?tripedal?with?two?forelimbs?(13.31???12.68%),?and?tripedal?with? 90 two?hindlimbs?(2.41???4.80%)?(Figure?4.2).??As?expected,?there?was?no?period?of? suspension?found?in?the?extended?jog.??? Vertical?excursion?was?greatest?for?the?withers?(0.16???0.20?m)?followed?by? the?head?(0.12???0.05?m),?hind?coffin?(0.11???0.01?m),?fore?coffin?(0.10???0.02?m),? and?the?croup?(0.10???0.01?m)?during?the?extended?jog.??A?statistical?difference? was?not?found?when?comparing?the?vertical?excursions?of?the?withers?to?croup? (P=0.99),?withers?to?head?(P=0.25),?or?croup?to?head?(P=0.31),?which?indicates?that? horses? exhibited? a? balanced? topline? when? performing? the? extended? jog? and,? therefore,?conform?to?breed?standards?concerning?gait?performance.? Angular?kinematics.? Peak? flexion? and? extension? as? well? as? joint? range? of? motion? for? the? shoulder,?elbow,?carpus,?fore?fetlock,?hip,?stifle,?hock,?and?hind?fetlock?joints?for? extended?jog?are?shown?in?Table?4.6.??The?greatest?ROM?was?seen?for?the?hind? fetlock?followed?by?the?fore?fetlock,?carpus,?and?elbow?joints;?the?shoulder?joint? exhibited?the?least?ROM.??Representative?fore?and?hindlimb?joint?kinematics?for? horses? at? the? extended? jog? are? graphically? presented? in? Figures? 4.5? and? 4.6.?? Graphs? were? plotted? from? consecutive? right? hind? touchdowns? as? a? percent? of? stride?and?represent?joint?flexion?or?extension?during?a?complete?stride.??Upward? inclinations? in? graphs? indicate? extension? of? the? joint? while? downward? 91 inclinations? indicate? flexion.??The? black? vertical? line? indicates? the? initiation? of? stance?phase?for?forelimb?graphs?and?the?initiation?of?swing?phase?for?hindlimb? graphs.??Forelimb?joint?motion?graphs?indicate?that?swing?phase?occurred?from?0? ??37%?of?the?stride?while?the?shoulder?gradually?extended?and?the?elbow,?carpus,? and?fetlock?gradually?flexed?(Figure?4.5).??Peak?flexion?of?the?carpus?occurred? prior?to?peak?flexion?of?the?elbow?and?fetlock?joints.??Stance?phase?occurred?from? 38???100%?of?the?stride?with?the?fore?hoof?making?contact?with?the?ground?at? around?37%?of?stride.??Gradual?extension?of?the?elbow?and?carpus?and?flexion?of? the?shoulder?continued?throughout?stance;?peak?extension?of?the?fetlock?occurred? at?mid?stance.? ? Hindlimb? joint? motion? graphs? indicate? that? the? first? 59%? of? stride? was? spent? in? stance? phase;? the? hip? gradually? extended? throughout? stance? to? reach? peak?extension?at?late?stance?(Figure?4.6).??The?hock?reached?peak?extension?at? 45%? of? stride? and? then? gradually? flexed? to? reach? peak? flexion? at? early? swing? phase.??Swing?phase?occurred?from?60???100%?of?the?stride?while?the?shoulder,? stifle,?and?hock?gradually?flexed.??Peak?extension?of?the?fetlock?occurred?during? mid? stance,? and? peak? flexion? occurred? during? early? swing? phase? just? prior? to? peak?flexion?of?the?stifle?and?hock.? ? 92 Table? 4.6:??Means? (?? s.d.)? for? peak? flexion? and? extension? joint? angles? (deg)? measured?on?the?flexor?side?of?the?joint?and?range?of?motion?(ROM)?(deg)?for? fore?and?hindlimbs?at?the?extended?jog.? Joint? Peak?Flexion?(deg)? Peak?Extension?(deg)? Joint?ROM?(deg)? Forelimb? ?????Shoulder? 110.32?(7.15)? 118.48?(7.14)? 8.16?(1.59)? ?????Elbow? 93.12?(8.09)? 148.48?(6.59)? 55.37?(4.07)? ?????Carpus? 117.15?(4.50)? 181.84(2.71)? 64.70?(4.68)? ?????Fetlock? 151.07?(5.18)? 231.27?(9.45)? 80.20?(6.77)? Hindlimb? ?????Hip? 99.99?(4.29)? 116.21?(3.56)? 16.22?(1.55)? ?????Stifle? 135.44?(7.88)? 172.60?(6.54)? 37.16?(4.53)? ?????Hock? 131.35?(6.13)? 167.36?(4.35)? 36.01?(4.38)? ?????Fetlock? 144.62?(4.96)? 232.49?(10.11)? 87.87?(9.77)? ? Extended?Jog?Forelimb?Joint?Motion 80 100 120 140 160 180 200 220 240 260 0% 20% 40% 60% 80% 100% Stride?(%) Angle ? (deg) Shoulder Elbow Carpus Fetlock Figure? 4.5:??Representative? forelimb? motion? graph? of? the? shoulder,? elbow,? carpus,?and?fetlock?joints?(deg)?as?a?percentage?of?stride?(%)?for?one?stride?of? the?extended?jog?of?the?stock?breed?western?pleasure?horse.??The?gait?cycle?was? right?hind?hoof?contact?to?the?next?contact?of?the?right?hind?hoof,?and?the?black? vertical?line?indicates?the?initiation?of?stance?phase.??? 93 Extended?Jog?Hindlimb?Joint?Motion 80 100 120 140 160 180 200 220 240 260 0% 20% 40% 60% 80% 100% Stride?(%) Angle ? (deg) Hip Stifle Hock Fetlock Figure?4.6:??Representative?hindlimb?motion?graph?of?the?hip,?stifle,?hock,?and? fetlock?joints?(deg)?as?a?percentage?of?stride?(%)?for?one?stride?of?the?extended? jog?of?the?stock?breed?western?pleasure?horse.??The?gait?cycle?was?right?hind? hoof?contact?to?the?next?contact?of?the?right?hind?hoof,?and?the?black?vertical? line?indicates?the?initiation?of?stance?phase.??? Collected?versus?Extended?Jog? ? Temporal?and?linear?kinematics.? Both?the?collected?and?extended?jog?exhibited?a?lateral?footfall?sequence? (Figure? 4.1);? however,? due? to? the? large? number? of? variables? analyzed? and? the? relatively?small?sample?size,?there?were?insufficient?residual?degrees?of?freedom? to? perform? a? multivariate? ANOVA? for? either? the? temporal? or? linear? variables.?? Therefore,? the? univariate? results? are? presented? cautiously? and? with? the? 94 understanding?of?the?risk?of?type?1?errors?being?increased?due?to?the?number?of? comparisons?being?performed.??Although?a?significance?level?of?95%?was?chosen? for? statistical? comparisons,? all? variables? that? were? deemed? significant? had? a? univariate?P?value?less?than?or?equal?to?0.009.??Therefore,?the?risk?of?type?1?errors? is? acceptably? small,? even? considering? the? number? of? comparisons? being? performed.??? Stride? length? was? longer? for? the? extended? jog? and? indicated? significant? statistical? significance? (P?0.05)? from? the? collected? jog? (Table? 4.7).??Horses? also? performed? the? extended? jog? with? a? velocity? that? was? statistically? significant? (P?0.05)?from?the?velocity?of?the?collected?jog.??As?well,?vertical?excursion?of?the? hip? indicated? statistical? significance? (P?0.05).??The? display? of? greater? vertical? excursion? at? the? hip? when? at? the? extended? jog? than? when? performing? the? collected? jog? indicates? that? the? extended? jog? exhibited? greater? lift? in? the? hindlimbs? than? did? the? collected? jog.??Stride? duration,? diagonal? advanced? placement? and? bipedal? limb? support?indicated?temporal?statistical?significance? (P?0.05)?when?compared?between?the?collected?and?extended?jog.??The?shorter? time?seen?for?diagonal?advanced?placement?when?performing?the?extended?than? when? performing? the? collected? jog? indicates? that? diagonal? pairs? moved? more? closely? together? in? time? during? the? extended? jog? than? in? the? collected? jog.?? Additionally,?the?increase?in?percentage?of?stride?spent?in?diagonal?bipedal?limb? 95 support?at?extended?jog?infers?that?horses?were?exhibiting?a??more?diagonal??gait? than?seen?in?the?collected?jog.??No?statistical?significance?was?found?between?the? collected?and?extended?jogs?for?the?linear?variables?of?vertical?excursions?for?the? head?(P=0.61),?withers?(P=0.33),?fore?coffin?(P=0.38),?or?hind?coffin?(P=0.68);?no? statistical? significance? was? found? for? the? temporal? variables? of? diagonal? advanced?lift?off?(P=0.34),?lateral?advanced?placement?(P=0.15),?lateral?advanced? lift?off?(P=0.07),?or?limb?support?phases?of?tripedal?with?two?hindlimbs?(P=0.31),? tripedal?with?two?forelimbs?(P=0.46),?or?quadrupedal?(P=0.10).?Similarities?and? differences? in? temporal? and? linear? kinematics? between? the? collected? and? extended? jog? were? congruent? with? the? scientific,? breed? association,? and? visual? interpretation?of?the?gait?due?to?the?collected?jog?being?a?slower,?less?forward? moving?gait?than?the?extended?jog.? 96 Table?4.7:??Statistically?significant?different?(P?0.05)?means?(??s.d.)?for?temporal? and? linear? variables? of? stride? length? (m),? stride? duration? (s),? velocity? (m/s),? vertical?excursion?of?the?hip?(m),?diagonal?advanced?placement?(s),?and?diagonal? bipedal?limb?support?for?stock?breed?western?pleasure?horses?at?the?collected?and? extended?jog?(LH???left?hind,?LF???left?fore,?RH???right?hind,?RF???right?fore).??? ? Collected?Jog ? Extended?Jog ? Stride?Length?(m)? 1.28?(0.17) ? 1.42?(0.16)? Stride?Duration?(s)? 1.91?(0.12)? 1.75?(0.08)? Velocity?(m/s)? 0.67?(0.01)? 0.82?(0.01)? Vertical?Excursion?of?the?Hip?(m)? 0.08?(0.01)? 0.10?(0.01)? Diagonal?Advanced?Placement?(s)? 0.13?(0.05)? 0.06?(0.03)? Diagonal?Bipedal?Limb?Support?(%)? 57.78?(10.48)? 70.20?(7.37)? ? Angular?kinematics.? ? Due? to? the? large?number?of?variables?analyzed?and?the?relatively?small? sample? size,? there? were? insufficient? residual? degrees? of? freedom? to? perform? a? multivariate?ANOVA?for?the?angular?variables.??Therefore,?the?univariate?results? are?presented?cautiously?and?with?the?understanding?of?the?risk?of?type?1?errors? being?increased?due?to?the?number?of?comparisons?being?performed.??Although?a? significance?level?of?95%?was?chosen?for?statistical?comparisons,?all?variables?that? were? deemed? significant? had? a? univariate? P? value? less? than? or? equal? to? 0.02.?? Therefore,? the? risk? of? type? 1? errors? is? acceptably? small,? even? considering? the? number?of?comparisons?being?performed.??? Angular?variables?indicating?statistical?significance?(P?0.05)?between?the? collected?and?extended?jog?include?peak?hip?extension?and?peak?stifle?flexion,? 97 extension,?and?ROM?(Table?4.8).??Differences?in?these?joints?seem?to?indicate?that? the? distinction? between? the? collected? and? extended? jog? are? most? likely? due? to? variation?in?hindlimb?kinematics.??No?statistical?significance?was?seen?for?peak? extension?of?the?shoulder?(P=0.69),?carpus?(P=0.36),?or?hock?(P=0.38);?peak?flexion? of?the?shoulder?(P=0.42),?carpus?(P=0.27),?hip?(P=0.72),?or?hock?(P=0.22);?or?ROM? of? the? shoulder? (P=0.20),? carpus? (P=0.60),? hip? (P=0.07),? or? hock? (P=0.07)? joints? when? compared? between? the? collected? and? extended? jogs.??Motion? graphs? indicated?the?same?trends?in?joint?motion?between?the?collected?and?extended? jogs?(Figures?4.3???4.6).?? ? Table?4.8:??Statistically?significant?(P?0.05)?means?(??s.d.)?for?angular?variables? (deg)?of?peak?flexion,?peak?extension,?and?range?of?motion?(ROM)?for?stock?breed? western?pleasure?horses?at?the?collected?and?extended?jog.??? ? Collected?Jog ? Extended?Jog ? Hip? ?????Peak?Extension? 115.48?(3.46)? 116.21?(3.56)? Stifle? ?????Peak?Flexion? 136.81?(7.93)? 135.44?(7.88)? ?????Peak?Extension? 168.81?(6.90)? 172.60?(6.54)? ?????ROM? 32.00?(4.48)? 37.16?(4.53)? ? ? ? ? ? 98 LH LF RH RF 2 LH LF RH RF 1 LH LF RH RF 3 LH LF RH RF 4 Collected?Lope? ? Right?lead?temporal?and?linear?kinematics.? ? Horses? performed? the? right? lead? collected? lope? with? right? limbs? on? the? leading? side? of? the? body? and? left? limbs? on? the? trailing? side;? the? right? lead? collected?lope?(n=6)?had?a?diagonal?footfall?sequence?of?trailing?hind?(left?hind)? followed?by?leading?hind?(right?hind)?and?trailing?fore?(left?fore),?working?as?a? diagonal? pair,? followed? by? the? leading? forelimb? (right? fore)? (Figure? 4.7).?? Disuniting? of? the? diagonal? pair? was? seen? in? 72.22%? of? strides? with? 61.54%? of? those?strides?showing?a?diagonal?footfall?sequence?as?the?leading?hindlimb?(right? hind)?made?contact?with?the?ground?an?instant?before?the?trailing?fore?(left?fore).?? Disuniting?of?the?diagonal?pair?gave?the?lope?a?four?beat?rhythm,?which?does?not? conform?to?the?breed?standard?for?gait?performance.??? ? ? Figure? 4.7:? Diagonal? footfall? sequence? of? the? right? lead? collected? lope? as? performed? by? the? stock? breed? western? pleasure? horse.??Each? circle? is? representative?of?a?horse?s?hoof?(LH???left?hind,?LF???left?fore,?RH???right?hind,?RF? ??right?fore).? ? 99 ? Mean?stride?length?was?1.57???0.18?m?when?calculated?from?consecutive? right?hind?down?placements?and?1.44???0.11?m?when?calculated?from?consecutive? left? hind? down? placements? and? approached? statistical? significance? when? compared? (P=0.05).??This? longer? stride? length? seen? for? the? right? hind? when? compared?to?the?left?hind?seems?visually?counterintuitive?because?the?left?hind,? as?the?trailing?hind,?appears?to?have?the?longer?stride?length.??Stride?duration? indicated? a? significant? statistical? difference? (P?0.05)? when? calculated? from? consecutive? right? hind? down? placements? (1.35? ?? 0.07? s)? than? when? calculated? from? consecutive? left? hind? down? placements? (1.37? ?? 0.06? s).??These? measures? indicate?that?while?the?stride?length?was?longer?when?calculated?from?right?hind? to? right? hind? than? left? hind? to? left? hind,? stride? duration? was? shorter? when? calculated?from?right?hind?to?right?hind?than?left?hind?to?left?hind?and?indicates? that? the? lope? is? performed? according? to? breed? and? scientific? standards? as? an? asymmetrical?gait.??Stride?frequency?also?showed?statistical?significance?(P?0.05)? when? calculated? from? consecutive? right? hind? down? placements? (0.74? ?? 0.04? stride/s)?than?when?calculated?from?consecutive?left?hind?down?placements?(0.73? ??0.03?stride/s).??Horses?performed?the?right?lead?collected?lope?with?a?velocity?of? 1.16???0.15?m/s.??Hind?step?length?was?0.60????0.19?m?and?fore?step?length?was?0.59? ??0.15?m,?each?consisting?of?approximately?one?half?of?the?total?stride?length.??? 100 Statistical?significance?was?found?between?the?stance?and?swing?durations? of? the? left? and? right? hind? (P?0.05),? and? interestingly,? the? only? swing? duration? comparison? not?yielding?statistical?significance?(P=0.14)?was?between?the?right? and?left?fore?limbs?(Table?4.9?&?4.10).??Statistical?significance?was?found?between? left? and? right? lateral? advanced? placement,? diagonal? advanced? placement,? and? diagonal?advanced?lift?off?(P?0.05)?(Table?4.11).??Significant?differences?observed? between?left?and?right?variables?of?hind?stance?and?swing?durations?as?well?as?the? differences? between? lateral? and? diagonal? advanced? placement? and? lift?off? indicated?that?the?lope?was?asymmetrical?as?dictated?by?both?scientific?and?breed? definitions.?? ? Table?4.9:??Means?(??s.d.)?for?stance?durations?(s)?for?the?following?limbs?of?each? stock? breed? western? pleasure? horse? (Subject? 1?6)? at? the? right? lead? collected? lope:?right?hind?(RH)?and?left?hind?(LH).??? Subject? RH?(s) ? LH?(s) ? 1? 0.83?(0.03) a 0.72?(0.02) b 2? 0.89?(0.02) a 0.83?(0.03) b 3? 0.81?(0.05) a 0.75?(0.02) b 4? 0.73?(0.03) a 0.69?(0.04) b 5? 0.81?(0.02) a 0.72?(0.07) b 6? 0.81?(0.04) a 0.75?(0.05) b Mean?(??s.d.) 0.81?(0.05) a? 0.75?(0.05) b Means? (?? s.d.)? within? the? same? row? followed? by? different? letters? are? significantly?different?at?P?0.05.??? ? ? ? 101 Table?4.10:??Means?(??s.d.)?for?swing?durations?(s)?for?the?following?limbs?of? each?stock?breed?western?pleasure?horse?(Subject?1?6)?at?the?right?lead?collected? lope:?right?hind?(RH),?left?hind?(LH),?right?fore?(RF),?and?left?fore?(LF).??? Subject? RH?(s) ? LH?(s) ? RF?(s) ? LF?(s) ? 1? 0.54?(0.02) a? 0.69?(0.04) b 0.82?(0.04) c 0.81?(0.02) c 2? 0.56?(0.04) a 0.63?(0.06) b 0.84?(0.04) c 0.82?(0.02) c 3? 0.49?(0.02) a 0.56?(0.04) b 0.67?(0.15) c 0.83?(0.00) c 4? 0.52?(0.02) a 0.61?(0.02) b 0.72?(0.02) c 0.77?(0.00) c 5? 0.57?(0.00) a 0.65?(0.02) b 0.74?(0.02) c 0.81?(0.02) c 6? 0.57?(0.03) a 0.63?(0.03) b 0.83?(0.00 ?c ? 0.88?(0.02) c Mean?(??s.d.)? 0.54?(0.03) a? 0.62?(0.04) b? 0.77?(0.07) c? 0.82?(0.04) c? Means?(??s.d.)?within?the?same?row?followed?by?different?letters?are? significantly?different?at?P?0.05.??? ? ? Table?4.11:??Means?(??s.d.)?for?left?and?right?lateral?and?diagonal?advanced? placements?and?lift?offs?(s)?for?stock?breed?western?pleasure?horses?at?the?right? lead?collected?lope:??left?lateral?=?LF?LH,?right?lateral?=?RF?RH,?left?diagonal?=? RF?LH,?and?right?diagonal?=?LF?RH.?? ? Left? Right? Lateral?Advanced?Placement?(s)? 0.40?(0.05) a? 0.49?(0.04) b? Diagonal?Advanced?Placement?(s)? 0.82?(0.15) a? 0.19?(0.39) b? Lateral?Advanced?Lift?off?(s)? 0.49?(0.04) a ? 0.49?(0.06) a ? Diagonal?Advanced?Lift?off?(s)? 0.85?(0.18) a? 0.09?(0.12) b? Means?(??s.d.)?within?the?same?row?followed?by?different?letters?are? significantly?different?at?P?0.05.??? ? ? During?the?right?lead?collected?lope,?horses?exhibited?eight?different?limb? support?phases:??1)?diagonal?bipedal?(RF?LH),?2)?unipedal?hind?(LH),?3)?bipedal? hind?(RH?LH),?4)?tripedal?with?two?hindlimbs?(LF?RH?LH),?5)?diagonal?bipedal? (LF?RH),?6)?tripedal?with?two?forelimbs?(RF?LF?RH),?7)?lateral?bipedal?(RF?RH),? and?8)?unipedal?fore?(RF)?(Figure?4.8).??However,?some?horses?displayed?alternate? limb? support? strategies? in? place? of? phases? three? and? seven.??Two? horses? 102 LH LF RH RF 2 LH LF RH RF 3 1 LH LF RH RF LH LF RH RF 5 LH LF RH RF 6 LH LF RH RF 7 LH LF RH RF 8 RH LH LF 4 RF exchanged? phase? three,? one? stride? each,? with? lateral? bipedal? (LF?LH)? support;? four? horses? exchanged? phase? seven,? 2.25? ?? 0.96? strides? each,? with? bipedal? forelimb? (RF?LF)? support.??Tripedal? with? two? hindlimb? (LF?RH?LH)? support? occupied?the?greatest?percent?of?stride?followed?closely?by?diagonal?bipedal?(RF? LH),? tripedal? with? two? forelimbs? (RF?LF?RH),? diagonal? bipedal? (LF?RH),? unipedal? fore? (RF),? unipedal? hind? (LH),? bipedal? hind? (RH?LH),? and? lateral? bipedal? (RF?RH)? (Table? 4.12).??There? was? no? period? of? suspension? or? quadrupedal?limb?support?during?the?right?lead?collected?lope.? ? ? ? ? ? ? ? Figure?4.8:?Limb?support?phases?of?the?right?lead?collected?lope?as?performed? by?the?stock?breed?western?pleasure?horse.??Each?circle?is?representative?of?a? horse?s?hoof?(LH???left?hind,?LF???left?fore,?RH???right?hind,?RF???right?fore).??? ? ? ? 103 Table?4.12:??Means?(??s.d.)?for?limb?support?phases?as?a?percent?(%)?of?stride?for? stock?breed?western?pleasure?horses?at?the?right?lead?collected?lope.?? Limb?Support?Phase? Percent?of?Stride?(%)? Tripedal?with?two?Hindlimbs?(LF?RH?LH)? 22.54?(3.26)? Diagonal?Bipedal?(RF?LH)? 22.35?(3.41)? Tripedal?with?two?Forelimbs?(RF?LF?RH)? 22.14?(2.04)? Diagonal?Bipedal?(LF?RH)? 11.74?(4.87)? Unipedal?Fore?(RF)? 9.20?(2.16)? Unipedal?Hind?(LH)? 5.74?(2.71)? Bipedal?Fore?(LF?RF)*? 2.76?(2.69)? Bipedal?Hind?(LH?RH)? 2.05?(1.36)? Lateral?Bipedal?(RF?RH)? 1.18?(1.81)? Lateral?Bipedal?(LF?LH)*? 0.30?(0.46)? *?indicates?alternate?limb?support?strategies?utilized?by?some?horses.??? ? Vertical?excursion?was?greatest?for?the?head?(0.41???0.09?m)?followed?by? the?croup?(0.40???0.08?m),?trailing?hind?(LH)?coffin?(0.15???0.05?m),?leading?fore? (RF)?coffin?(0.15???0.02?m),?trailing?fore?(LF)?coffin?(0.15???0.03?m),?leading?hind? (RH)?coffin?(0.13???0.02?m),?and?the?withers?(0.12???0.01?m)?during?the?right?lead? collected?lope.??A?statistical?difference?was?found?when?comparing?the?vertical? excursions?of?the?head?to?withers?and?withers?to?croup?(P?0.05)?but?not?when? comparing?the?croup?to?head?(P=0.73),?which?indicates?that?horses?did?not?exhibit? a? balanced? topline? when? performing? the? right? lead? collected? lope? and? do? not? conform?to?the?breed?standard?concerning?gait?performance.? ? ? ? 104 Right?lead?angular?kinematics.? ? Peak? flexion? and? extension? as? well? as? joint? range? of? motion? (ROM)? for? shoulder,?elbow,?carpus,?fore?fetlock,?hip,?stifle,?hock,?and?hind?fetlock?joints?for? the?right?lead?collected?lope?are?shown?in?Table?4.13.??The?greatest?ROM?was?seen? for?the?fetlock?joint?of?all?four?limbs?followed?by?the?right?and?left?carpus?joints;? the?shoulder?joints?exhibited?the?least?ROM.??? ? Table? 4.13:??Means? (?? s.d.)? for? peak? flexion? and? extension? joint? angles? (deg)? measured?on?the?flexor?side?of?the?joint?and?range?of?motion?(ROM)?(deg)?for? fore?and?hindlimbs?at?the?right?lead?collected?lope:?right?hind?(RH),?left?hind? (LH),?right?fore?(RF),?and?left?fore?(LF).??? Joint? Peak?Flexion?(deg)? Peak?Extension?(deg)? Joint?ROM?(deg)? Leading Forelimb (RF)? ?????Shoulder? 113.26?(10.05)? 123.46?(8.92)? 10.21?(1.61)? ?????Elbow? 87.45?(10.61)? 148.23?(9.53)? 60.78?(3.59? ?????Carpus? 109.77?(6.76)? 181.98?(2.97)? 72.21?(5.02)? ?????Fetlock? 143.51?(5.93)? 229.28?(11.19)? 85.76?(9.44)? Trailing?Forelimb?(LF)? ?????Shoulder? 108.09?(7.89)? 117.87?(6.66)? 9.78?(2.59)? ?????Elbow? 100.28?(9.43)? 144.89?(6.00)? 44.62?(4.73)? ?????Carpus? 121.82?(5.83)? 182.75?(2.81)? 60.93?(5.87)? ?????Fetlock? 144.97?(10.51)? 233.44?(10.34)? 88.47?(10.48)? Leading?Hindlimb?(RH)? ?????Hip? 100.44?(3.25)? 116.60?(5.64)? 16.16?(2.49)? ?????Stifle? 139.94?(8.42)? 176.53?(5.07)? 36.59?(6.52)? ?????Hock? 134.38?(4.19)? 167.25?(3.67)? 32.87?(3.14)? ?????Fetlock? 149.26?(7.72)? 233.80?(13.37)? 84.53?(17.73)? Trailing?Hindlimb?(LH)? ?????Hip? 102.95?(3.82)? 121.41?(3.39)? 18.45?(3.70)? ?????Stifle? 136.35?(7.78)? 167.88?(10.05)? 31.54?(4.69)? ?????Hock? 137.74?(6.24)? 168.37?(4.25)? 30.62?(6.75)? ?????Fetlock? 150.03?(11.88)? 233.38?(8.52)? 83.35?(17.76)? ? 105 Representative?fore?and?hindlimb?joint?kinematics?for?horses?at?the?right? lead?collected?lope?are?graphically?presented?in?Figures?4.9?through?4.12.??Graphs? were?plotted?from?hoof?contact?to?the?next?contact?of?the?same?hoof?as?a?percent? of?stride?and?represent?joint?flexion?or?extension?during?a?complete?stride;?the? black?vertical?line?indicates?the?initiation?of?swing?phase.??Upward?inclinations?in? graphs? indicate? extension? of? the? joint? while? downward? inclinations? indicate? flexion.??Leading?forelimb?(right?fore)?joint?motion?graphs?indicate?that?stance? phase? occurred? from? 0? ?? 50%? of? stride? during? which? the? elbow? and? carpus? gradually?extended?and?the?fetlock?reached?peak?extension?(Figure?4.9).???Swing? phase?occurred?from?51???100%?of?the?stride?while?the?elbow,?carpus,?and?fetlock? gradually?flexed.??The?shoulder?reached?peak?flexion?at?mid?swing;?peak?flexion? of?the?carpus?occurred?prior?to?peak?flexion?of?the?elbow?and?fetlock?joints.?? ? Trailing?forelimb?(left?fore)?joint?motion?graphs?indicate?that?stance?phase? occurred?from?0???47%?of?stride?during?which?the?elbow?and?carpus?gradually? extended? and? the? fetlock? reached? peak? extension? (Figure? 4.10).??The? shoulder? reached?peak?flexion?at?mid?stance?and?then?gradually?extended?throughout?the? remainder? of? the? stride.??Swing? phase? occurred? from? 48? ?? 100%? of? the? stride? during?which?time?the?elbow,?carpus,?and?fetlock?gradually?flexed.??Peak?flexion? of?the?carpus?occurred?prior?to?peak?flexion?of?the?elbow?and?fetlock?joints.? 106 Right?Lead?Collected?Lope?Leading?Forelimb?Joint?Motion 80 100 120 140 160 180 200 220 240 260 0% 20% 40% 60% 80% 100% Stride?(%) Angle ? (deg) Shoulder Elbow Carpus Fetlock Figure?4.9:??Representative?leading?forelimb?(right?fore)?motion?graph?of?the? shoulder,?elbow,?carpus,?and?fetlock?joints?(deg)?as?a?percentage?of?stride?(%)? for? one? stride? of? the? right? lead? collected? lope? of? the? stock? breed? western? pleasure?horse.??The?gait?cycle?was?right?fore?hoof?contact?to?the?next?contact?of? the?right?fore?hoof,?and?the?black?vertical?line?indicates?the?initiation?of?swing? phase.??? ? ? 107 Right?Lead?Collected?Lope?Trailing?Forelimb?Joint?Motion 80 100 120 140 160 180 200 220 240 260 0% 20% 40% 60% 80% 100% Stride?(%) Angle ? (deg) Shoulder Elbow Carpus Fetlock Figure?4.10:??Representative?trailing?forelimb?(left?fore)?motion?graph?of?the? shoulder,?elbow,?carpus,?and?fetlock?joints?(deg)?as?a?percentage?of?stride?(%)? for? one? stride? of? the? right? lead? collected? lope? of? the? stock? breed? western? pleasure?horse.??The?gait?cycle?was?left?fore?hoof?contact?to?the?next?contact?of? the?left?fore?hoof,?and?the?black?vertical?line?indicates?the?initiation?of?swing? phase.??? ? ? Leading? hindlimb? (right? hind)? joint? motion? graphs? indicate? that? stance? phase? occurred? from? 0? ?? 53%? of? stride? during? which? the? stifle,? and? hock? gradually?flexed?(Figure?4.11).??The?hip?reached?peak?extension?at?late?stance?and? then?gradually?flexed?throughout?the?stride;?the?fetlock?reached?peak?flexion?in? mid? stance? and? then? gradually? extended? throughout? the? stride.??Swing? phase? occurred?from?54???100%?of?the?stride?with?the?stifle?and?hock?indicating?double? 108 peaks?of?extension?one?in?early?swing?and?one?in?late?swing.??The?fetlock?reached? peak?flexion?in?early?swing.??? ? Trailing? hindlimb? (left? hind)? joint? motion? graphs? indicate? that? stance? phase?occurred?from?0???48%?of?stride?during?which?the?stifle?and?hock?gradually? flexed?and?then?extended?to?reach?peak?extension?at?late?stance?(Figure?4.12).??The? fetlock? reached? peak? extension? during? early? stance.??The? hip? reached? peak? extension? at? 25%? of? stride? and? then? gradually? flexed? throughout? the? stride.?? Swing?phase?occurred?from?49???100%?of?the?stride?while?the?stifle,?hock,?and? fetlock?gradually?flexed?with?peak?flexion?of?the?fetlock?occurring?prior?to?peak? flexion?of?the?stifle?and?hock?joints.? ? ? ? ? ? ? ? ? ? ? 109 ? ? ? Right?Lead?Collected?Lope?Leading?Hindlimb?Joint?Motion 80 100 120 140 160 180 200 220 240 260 0% 20% 40% 60% 80% 100% Stride?(%) Angle ? (deg) Hip Stifle Hock Fetlock Figure?4.11:??Representative?leading?hindlimb?(right?hind)?motion?graph?of?the? hip,?stifle,?hock,?and?fetlock?joints?(deg)?as?a?percentage?of?stride?(%)?for?one? stride?of?the?right?lead?collected?lope?of?the?stock?breed?western?pleasure?horse.?? The?gait?cycle?was?right?hind?hoof?contact?to?the?next?contact?of?the?right?hind? hoof,?and?the?black?vertical?line?indicates?the?initiation?of?swing?phase.??? ? ? ? ? ? ? ? ? ? ? 110 Right?Lead?Collected?Lope?Trailing?Hindlimb?Joint?Motion 80 100 120 140 160 180 200 220 240 260 0% 20% 40% 60% 80% 100% Stride?(%) Angle ? (deg) Hip Stifle Hock Fetlock Figure?4.12:??Representative?trailing?hindlimb?(left?hind)?motion?graph?of?the?hip,? stifle,?hock,?and?fetlock?joints?(deg)?as?a?percentage?of?stride?(%)?for?one?stride?of? the?right?lead?collected?lope?of?the?stock?breed?western?pleasure?horse.??The?gait? cycle?was?left?hind?hoof?contact?to?the?next?contact?of?the?left?hind?hoof,?and?the? black?vertical?line?indicates?the?initiation?of?swing?phase.??? ? ? Left?lead?temporal?and?linear?kinematics.? ? Horses? performed? the? left? lead? collected? lope? with? left? limbs? on? the? leading?side?of?the?body?and?right?limbs?on?the?trailing?side;?in?accordance?with? past? stock? breed? western? pleasure? research? (Nicodemus? and? Booker? 2007;? Nicodemus?and?Clayton?2001a),?the?left?lead?collected?lope?(n=6)?had?a?lateral? footfall?sequence?of?trailing?hind?(right?hind)?followed?by?trailing?fore?(right?fore)? and?leading?hind?(left?hind),?working?as?a?diagonal?pair,?followed?by?the?leading? forelimb? (left? fore)? (Figure? 4.13).??Disuniting? of? the? diagonal? pair? was? seen? in? 111 LH LF RH RF 3 LH LF RH RF 1 LH LF RH RF 4 LH LF RH RF 2 77.78%?of?strides?with?71.43%?of?those?strides?showing?a?lateral?footfall?sequence? as? the? trailing? forelimb? (right? fore)? made? contact? with? the? ground? an? instant? before?the?leading?hindlimb?(left?hind).??Disuniting?of?the?diagonal?pair?gave?the? lope?a?four?beat?rhythm,?which?does?not?conform?to?the?breed?standard?for?gait? performance.??Horses?performed?the?left?lead?collected?lope?with?a?mean?stride? length?of?1.50???0.17?m,?stride?duration?of?1.39???0.08?s,?stride?frequency?of?0.72??? 0.04?stride/s,?and?velocity?of?1.09???0.13?m/s.??No?statistically?significant?difference? was? found? between? stride? length? (P=0.35),? duration? (P=0.61),? or? frequency? (P=0.64)? when? calculated? from? consecutive? right? hind? placements? than? when? calculated?from?consecutive?left?hind?placements.?Hind?step?length?was?0.82???? 0.29?m?and?fore?step?length?was?0.60???0.35?m,?with?hind?step?length?making?up?a? greater?percent?of?the?stride.? ? ? ? ? Figure? 4.13:? Lateral? footfall? sequence? of? the? left? lead? collected? lope? as? performed? by? the? stock? breed? western? pleasure? horse.??Each? circle? is? representative?of?a?horse?s?hoof?(LH???left?hind,?LF???left?fore,?RH???right?hind,? RF???right?fore). ? ? 112 Statistical?significance?was?found?between?the?stance?and?swing?durations? of?the?left?and?right?hind?(P?0.05),?swing?duration?of?the?left?fore?and?left?hind,? and?swing?duration?of?the?right?fore?and?left?hind,?indicating?that?the?diagonal? pair?exhibited?significantly?different?swing?times?(Table?4.14?&?4.15).??Statistical? significance? was? found? between? left? and? right? diagonal? advanced? placements? and?lift?offs?(P?0.05)?(Table?4.16).??Significant?differences?observed?between?left? and?right?variables?of?hind?stance?and?swing?durations?and?diagonal?advanced? placements?and?lift?offs?indicated?that?the?lope?was?asymmetrical?as?dictated?by? both?scientific?and?breed?definitions.? ? ? Table?4.14:??Means?(??s.d.)?for?stance?durations?(s)?for?the?following?limbs?of? each?stock?breed?western?pleasure?horse?(Subject?1?6)?at?the?left?lead?collected? lope:?right?hind?(RH)?and?left?hind?(LH).????? Subject? RH?(s) ? LH?(s) ? 1? 0.64?(0.02) a 0.90?(0.06) b 2? 0.81?(0.02) a 0.96?(0.05) b 3? 0.74?(0.02) a 0.81?(0.02) b 4? 0.70?(0.03) a 0.77?(0.03) b 5? 0.71?(0.04) a 0.84?(0.04) b 6? 0.80?(0.00) a 0.81?(0.10) b Mean?(??s.d.) 0.73?(0.06) a 0.85?(0.07) b Means? (?? s.d.)? within? the? same? row? followed? by? different? letters? are? significantly?different?at?P?0.05.? ? ? ? ? ? ? 113 Table?4.15:??Means?(??s.d.)?for?swing?durations?(s)?for?the?following?limbs?of? each?stock?breed?western?pleasure?horse?(Subject?1?6)?at?the?left?lead?collected? lope:?right?hind?(RH),?left?hind?(LH),?right?fore?(RF),?and?left?fore?(LF).??? Subject? RH?(s) ? LH?(s) ? RF?(s) ? LF?(s) ? 1? 0.77?(0.00) a 0.52?(0.05) b 0.67?(0.15) b 0.62?(0.18) ac 2? 0.66?(0.07) a 0.62?(0.07) b 0.83?(0.06) b 0.90?(0.03) ac 3? 0.53?(0.00) a 0.48?(0.02) b 0.80?(0.03) b 0.76?(0.05) ac 4? 0.61?(0.02) a 0.57?(0.03) b 0.69?(0.20) b 0.69?(0.14) ac 5? 0.70?(0.06) a 0.56?(0.05) b 0.81?(0.05) b 0.79?(0.02) ac 6? 0.66?(0.08) a 0.58?(0.02) b 0.90?(0.12) b 0.83?(0.09) ac Mean?(??s.d.)? 0.65?(0.08) a 0.55?(0.05) b 0.78?(0.09) b? 0.76?(0.20) ac Means? (?? s.d.)? within? the? same? row? followed? by? different? letters? are? significantly?different?at?P?0.05.? ? ? Table? 4.16:??Means? (?? s.d.)? for? left? and? right? lateral? and? diagonal? advanced? placements?and?lift?offs?(s)?for?stock?breed?western?pleasure?horses?at?the?left? lead?collected?lope:??left?lateral?=?LF?LH,?right?lateral?=?RF?RH,?left?diagonal?=? RF?LH,?and?right?diagonal?=?LF?RH.????? ? Left? Right? Lateral?Advanced?Placement?(s)? 0.58?(0.17) a ? 0.47?(0.14) a ? Diagonal?Advanced?Placement?(s)? 0.16?(0.19) a? 0.80?(0.14) b? Lateral?Advanced?Lift?off?(s)? 0.47?(0.03) a ? 0.55?(0.12) a ? Diagonal?Advanced?Lift?off?(s)? 0.17?(0.21) a? 0.76?(0.23) b? Means? (?? s.d.)? within? the? same? row? followed? by? different? letters? are? significantly?different?at?P?0.05.? During?the?left?lead?collected?lope,?horses?exhibited?eight?different?limb? support?phases:??1)?diagonal?bipedal?(LF?RH),?2)?unipedal?hind?(RH),?3)?lateral? bipedal? (RF?RH),? 4)? tripedal? with? two? hindlimbs? (RF?RH?LH),? 5)? diagonal? bipedal?(RF?LH),?6)?tripedal?with?two?forelimbs?(RF?LF?LH),?7)?lateral?bipedal? (LF?LH),? and? 8)? unipedal? fore? (LF)? (Figure? 4.14).??However,? some? horses? displayed?alternate?limb?support?strategies?in?place?of?phases?three?and?seven.?? 114 LH LF RH RF 1 LH LF RH RF 2 LH LF RH RF 3 LH LF 4 LH LF RH RF 5 LH LF RH RF 6 LH LF RH RF 7 LH LF RH RF 8 Two?horses?exchanged?phase?three?(1.5???0.71?strides?each)?with?bipedal?hind? (RH?LH)? support;? two? horses? exchanged? phase? seven,? two? strides? each,? with? bipedal? forelimb? (RF?LF)? support.??Diagonal? bipedal? (LF?RH)? limb? support? occupied? the? greatest? percent? of? stride? followed? closely? by? tripedal? with? two? hindlimbs? (RF?RH?LH),? tripedal? with? two? forelimbs? (LF?RF?LH),? diagonal? bipedal?(RF?LH),?unipedal?fore?(LF),?unipedal?hind?(RH),?left?lateral?bipedal?(LF? LH),? and? right? lateral? bipedal? (RF?RH)? (Table? 4.17).??There? was? no? period? of? suspension?or?quadrupedal?limb?support?during?the?left?lead?collected?lope.? ? ? ? ? ? ? ? ? ? ? ? Figure?4.14:?Limb?support?phases?of?the?left?lead?collected?lope?as?performed? by?the?stock?breed?western?pleasure?horse.??Each?circle?is?representative?of?a? horse?s?hoof?(LH???left?hind,?LF???left?fore,?RH???right?hind,?RF???right?fore).? ? ? ? ? 115 Table?4.17:??Means?(??s.d.)?for?limb?support?phases?as?a?percent?(%)?of?stride?for? stock?breed?western?pleasure?horses?at?the?left?lead?collected?lope.??? Limb?Support?Phase? Percent?of?Stride?(%)? Diagonal?Bipedal?(LF?RH)? 22.29?(4.94)? Tripedal?with?two?Hindlimbs?(RF?RH?LH)? 20.85?(4.04)? Tripedal?with?two?Forelimbs?(RF?LF?LH)? 20.70?(3.50)? Diagonal?Bipedal?(RF?LH)? 14.12?(4.44)? Unipedal?Fore?(LF)? 10.00?(3.78)? Unipedal?Hind?(RH)? 5.52?(3.96)? Lateral?Bipedal?(LF?LH)? 2.66?(2.72)? Lateral?Bipedal?(RF?RH)? 2.06?(1.56)? Bipedal?Fore?(LF?RF)*? 1.39?(2.67)? Bipedal?Hind?(LH?RH)*? 0.40?(0.67)? *?indicates?alternate?limb?support?strategies?utilized?by?some?horses? ? ? Vertical?excursion?was?greatest?for?the?croup?(0.51???0.13?m)?followed?by? the?head?(0.42???0.11?m),?trailing?fore?(RF)?coffin?(0.17???0.02?m),?leading?hind? (LH)?(0.16???0.04?m),?trailing?hind?(RH)?coffin?(0.14???0.02?m),?withers?(0.12???0.01? m),?and?the?leading?fore?(LF)?coffin?(0.12???0.02?m)?during?the?left?lead?collected? lope.??A?statistical?difference?was?found?when?comparing?the?vertical?excursions? of?the?head?to?withers?and?withers?to?croup?(P?0.05)?but?not?when?comparing?the? croup?to?head?(P=0.72),?which?indicates?that?horses?did?not?exhibit?a?balanced? topline?when?performing?the?left?lead?collected?lope?and?do?not?conform?to?the? breed?standard.? ? ? ? ? ? 116 Left?lead?angular?kinematics.?? ?? Peak? flexion? and? extension? as? well? as? joint? range? of? motion? (ROM)? for? shoulder,?elbow,?carpus,?fore?fetlock,?hip,?stifle,?hock,?and?hind?fetlock?joints?for? the?left?lead?collected?lope?are?shown?in?Table?4.18.??The?greatest?ROM?was?seen? for?the?fetlock?joint?of?all?four?limbs?followed?by?the?right?and?left?carpus?joints;? the?shoulder?joints?exhibited?the?least?ROM.??? ? Table? 4.18:??Means? (? s.d.)? for? peak? flexion? and? extension? joint? angles? (deg)? measured?on?the?flexor?side?of?the?joint?and?range?of?motion?(ROM)?(deg)?for? fore? and? hindlimbs? at? the? left? lead? collected? lope:? right? hind? (RH),? left? hind? (LH),?right?fore?(RF),?and?left?fore?(LF).??? Joint? Peak?Flexion?(deg)? Peak?Extension?(deg)? Joint?ROM?(deg)? Leading Forelimb (LF)? ?????Shoulder? 110.07?(5.81)? 119.62?(5.93)? 9.53?(1.10)? ?????Elbow? 88.27?(8.30)? 147.97?(9.75)? 59.70?(2.97)? ?????Carpus? 112.89?(6.40)? 182.56?(3.83)? 69.67?(4.66)? ?????Fetlock? 143.47?(7.73)? 227.60?(7.74)? 84.13?(6.74)? Trailing?Forelimb?(RF)? ?????Shoulder? 109.82?(9.61)? 119.86?(8.73)? 10.04?(2.69)? ?????Elbow? 95.19?(11.64)? 145.44?(8.24)? 50.25?(6.08)? ?????Carpus? 118.63?(3.67)? 181.69?(2.75)? 63.06?(3.92)? ?????Fetlock? 142.65?(8.53)? 234.02?(10.85)? 91.37?(6.39)? Leading?Hindlimb?(LH)? ?????Hip? 99.78?(3.16)? 113.55?(3.43)? 13.77?(2.01)? ?????Stifle? 141.51?(7.19)? 177.65?(10.45)? 36.15?(3.99)? ?????Hock? 139.34?(4.68)? 168.57?(4.27)? 29.23?(3.72)? ?????Fetlock? 147.53?(8.98)? 232.57?(7.56)? 85.04?(10.83)? Trailing?Hindlimb?(RH)? ?????Hip? 103.84?(3.86)? 122.80?(4.96)? 18.96?(2.86)? ?????Stifle? 133.34?(5.50)? 166.46?(3.60)? 33.12?(3.43)? ?????Hock? 131.80?(6.38)? 167.23?(5.31)? 35.43?(5.46)? ?????Fetlock? 153.95?(8.29)? 234.33?(13.88)? 80.38?(16.02)? 117 Representative? fore? and? hindlimb? joint? kinematics? for? horses? at? the? left? lead? collected? lope? are? graphically? presented? in? Figures? 4.15? through? 4.18.?? Graphs?were?plotted?from?hoof?contact?to?the?next?contact?of?the?same?hoof?as?a? percent? of? stride? and? represent? joint? flexion? or? extension? during? a? complete? stride;? the? black? vertical? line? indicates? the? initiation? of? swing? phase.??Upward? inclinations? in? graphs? indicate? extension? of? the? joint? while? downward? inclinations? indicate? flexion.??Leading? forelimb? (left? fore)? joint? motion? graphs? indicate? that? stance? phase? occurred? from? 0? ?? 49%? of? stride? during? which? the? elbow? and? carpus? gradually? extended? and? the? fetlock? reached? peak? extension? (Figure?4.15).??The?shoulder?gradually?flexed?throughout?stance.??Swing?phase? occurred? from? 51? ?? 100%? of? the? stride? while? the? elbow,? carpus,? and? fetlock? gradually?flexed.??Peak?flexion?of?the?carpus?occurred?prior?to?peak?flexion?of?the? elbow?and?fetlock?joints;?peak?extension?of?the?shoulder?occurred?in?early?swing.? Trailing? forelimb? (right? fore)? joint? motion? graphs? indicate? that? stance? phase? occurred? from? 0? ?? 47%? of? stride? during? which? the? elbow? and? carpus? gradually?extended?and?the?fetlock?reached?peak?extension?(Figure?4.16).??The? shoulder?reached?peak?flexion?at?19%?of?stride?and?then?extended?throughout?the? stride.??Swing? phase? occurred? from? 48? ?? 100%? of? the? stride? while? the? elbow,? carpus,?and?fetlock?gradually?flexed.??Peak?flexion?of?the?carpus?occurred?prior?to? peak?flexion?of?the?elbow?and?fetlock?joints.? 118 Collected?Lope?Left?Lead?Leading?Forelimb?Joint?Motion 60 80 100 120 140 160 180 200 220 240 260 0% 20% 40% 60% 80% 100% Stride?(%) Angle ? (deg) Shoulder Elbow Carpus Fetlock Figure?4.15:??Representative?leading?forelimb?(left?fore)?motion?graph?of?the? shoulder,?elbow,?carpus,?and?fetlock?joints?(deg)?as?a?percentage?of?stride?(%)? for?one?stride?of?the?left?lead?collected?lope?of?the?stock?breed?western?pleasure? horse.??The?gait?cycle?was?left?fore?hoof?contact?to?the?next?contact?of?the?left? fore?hoof,?and?the?black?vertical?line?indicates?the?initiation?of?swing?phase.??? ? ? ? ? ? ? ? ? 119 Collected?Lope?Left?Lead?Trailing?Forelimb?Joint?Motion 60 80 100 120 140 160 180 200 220 240 260 0% 20% 40% 60% 80% 100% Stride?(%) Angle ? (deg) Shoulder Elbow Carpus Fetlock Figure?4.16:??Representative?trailing?forelimb?(right?fore)?motion?graph?of?the? shoulder,?elbow,?carpus,?and?fetlock?joints?(deg)?as?a?percentage?of?stride?(%)? for? one? stride? of? the? left? lead? collected? lope? of? the? stock? breed? western? pleasure?horse.??The?gait?cycle?was?right?fore?hoof?contact?to?the?next?contact? of? the? right? fore? hoof,? and? the? black? vertical? line?indicates?the?initiation?of? swing?phase.??? ? Leading? hindlimb? (left? hind)? joint? motion? graphs? indicate? that? stance? phase? occurred? from? 0? ?? 57%? of? stride? during? which? the? hip,? stifle,? and? hock? gradually? flexed? and? then? extended? (Figure? 4.17).??The? hip? reached? peak? extension?in?late?stance?and?then?gradually?flexed?throughout?swing?phase;?the? fetlock? reached? peak? extension? at? late? stance? and? then? gradually? flexed? throughout?swing?phase.??Swing?phase?occurred?from?58???100%?of?the?stride? with? the? stifle? and? hock? reaching? peak? flexion? at? mid? swing,? and? the? fetlock? reaching?peak?flexion?in?early?swing.??? 120 Trailing? hindlimb? (right? hind)? joint? motion? graphs? indicate? that? stance? phase?occurred?from?0???49%?of?stride?during?which?the?stifle?and?hock?gradually? flexed?and?then?extended,?and?the?fetlock?reached?peak?extension?at?20%?of?stride? (Figure? 4.18).??The? hip? reached? peak? extension? at? 30%? of? stride? and? then? gradually?flexed?throughout?the?stride.??Swing?phase?occurred?from?50???100%?of? the?stride?while?the?stifle,?hock,?and?fetlock?gradually?flexed.??Peak?flexion?of?the? fetlock?occurred?prior?to?peak?flexion?of?the?stifle?and?hock?joints.? Collected?Lope?Left?Lead?Leading?Hindlimb?Joint?Motion 60 80 100 120 140 160 180 200 220 240 260 0% 20% 40% 60% 80% 100% Stride?(%) Angle ? (deg) Hip Stifle Hock Fetlock Figure?4.17:??Representative?leading?hindlimb?(left?hind)?motion?graph?of?the? hip,?stifle,?hock,?and?fetlock?joints?(deg)?as?a?percentage?of?stride?(%)?for?one? stride?of?the?left?lead?collected?lope?of?the?stock?breed?western?pleasure?horse.?? The?gait?cycle?was?left?hind?hoof?contact?to?the?next?contact?of?the?left?hind? hoof,?and?the?black?vertical?line?indicates?the?initiation?of?swing?phase.??? ? ? ? 121 Collected?Lope?Left?Lead?Trailing?Hindlimb?Joint?Motion 60 80 100 120 140 160 180 200 220 240 260 0% 20% 40% 60% 80% 100% Stride?(%) Angle ? (deg) Hip Stifle Hock Fetlock Figure?4.18:??Representative?trailing?hindlimb?(right?hind)?motion?graph?of?the? hip,? stifle,? hock,? and? fetlock? joints? (deg)? as? a? percentage? of? stride? (%)? for? one? stride?of?the?left?lead?collected?lope?of?the?stock?breed?western?pleasure?horse.?? The?gait?cycle?was?right?hind?hoof?contact?to?the?next?contact?of?the?right?hind? hoof,?and?the?black?vertical?line?indicates?the?initiation?of?swing?phase. ? ? ? Extended?Lope? ? Right?lead?temporal?and?linear?kinematics.? ? Horses? performed? the? right? lead?extended?lope?with?right?limbs?on?the? leading? side? of? the? body? and? left? limbs? on? the? trailing? side;? the? right? lead? collected? lope? (n=6)? had? a? lateral? footfall? sequence? of? trailing? hind? (left? hind)? followed?by?trailing?fore?(left?fore)?and?leading?hind?(right?hind),?working?as?a? diagonal? pair,? followed? by? the? leading? forelimb? (right? fore)? (Figure? 4.19).?? 122 LH LF RH RF 1 LH LF RH RF 2 LH LF RH RF 3 LH LF RH RF 4 Disuniting? of? the? diagonal? pair? was? seen? in? 77.78%? of? strides? with? 57.14%? of? those? strides? showing? a? lateral? footfall? sequence? as? the? trailing? fore? (left? fore)? made? contact? with? the? ground? an? instant? before? the? leading? hindlimb? (right? hind).??Disuniting?of?the?diagonal?pair?gave?the?lope?a?four?beat?rhythm,?which? does?not?conform?to?the?breed?standard?for?gait?performance.??Horses?performed? the?right?lead?extended?lope?with?a?mean?stride?length?of?1.68???0.15?m,?stride? duration?of?1.32???0.08?s,?stride?frequency?of?0.76???0.05?stride/s,?and?velocity?of? 1.28???0.12?m/s.??No?statistically?significant?difference?was?found?between?stride? length?(P=0.07),?duration?(P=0.18),?or?frequency?(P=0.18)?when?calculated?from? consecutive? right? hind? placements? than? when? calculated? from? consecutive? left? hind?placements.??Hind?step?length?was?0.80????0.26?m?and?fore?step?length?was? 0.76???0.19?m,?with?hind?step?length?making?up?a?greater?percent?of?the?stride.? ? ? ? ? Figure? 4.19:? Lateral? footfall? sequence? of? the? right? lead? extended? lope? as? performed? by? the? stock? breed? western? pleasure? horse.??Each? circle? is? representative?of?a?horse?s?hoof?(LH???left?hind,?LF???left?fore,?RH???right?hind,? RF???right?fore).? ? ? ? 123 Statistical?significance?was?found?between?the?stance?and?swing?durations? of? the? left? and? right? hind? (P?0.05),? and? interestingly,? the? only? swing? duration? comparison? not?yielding?statistical?significance?(P=0.28)?was?between?the?right? and?left?fore?limbs?(Table?4.19?&?4.20).??Statistical?significance?was?found?between? left?and?right?lateral?advanced?placement?and?diagonal?advanced?lift?off?(P?0.05)? (Table?4.21).??Significant?differences?observed?between?left?and?right?variables?of? hind?stance?and?swing?durations?and?lateral?and?diagonal?advanced?placement? and?lift?off?indicated?that?the?lope?was?asymmetrical?as?dictated?by?both?scientific? and?breed?definitions.?? Table?4.19:??Means?(??s.d.)?for?stance?durations?(s)?for?the?following?limbs?of? each?stock?breed?western?pleasure?horse?(Subject?1?6)?at?the?right?lead? extended?lope:?right?hind?(RH)?and?left?hind?(LH).??? Subject? RH?(s) ? LH?(s) ? 1? 0.81?(0.05) a 0.64?(0.02) b 2? 0.84?(0.04) a 0.72?(0.02) b 3? 0.71?(0.02) a 0.63?(0.03) b 4? 0.67?(0.03) a 0.60?(0.03) b 5? 0.74?(0.07) a 0.68?(0.02) b 6? 0.76?(0.05) a 0.68?(0.04) b Mean?(??s.d.) 0.75?(0.06) a 0.66?(0.04) b Means? (?? s.d.)? within? the? same? row? followed? by? different? letters? are? significantly?different?at?P?0.05.? ? ? ? ? ? ? ? 124 ? ? Table?4.20:??Means?(??s.d.)?for?swing?durations?(s)?for?the?following?limbs?of? each? stock? breed? western? pleasure? horse? (Subject? 1?6)? at? the? right? lead? extended?lope:?right?hind?(RH),?left?hind?(LH),?right?fore?(RF),?and?left?fore? (LF).??? Subject? RH?(s) ? LH?(s) ? RF?(s) ? LF?(s) ? 1? 0.58?(0.02) a 0.70?(0.03) b 0.86?(0.07) c 0.74?(0.02) c 2? 0.57?(0.00) a 0.67?(0.03) b 0.77?(0.67) c 0.80?(0.03) c 3? 0.50?(0.03) a 0.56?(0.04) b 0.67?(0.03) c 0.74?(0.04) c 4? 0.58?(0.02) a 0.62?(0.02) b 0.67?(0.03) c 0.74?(0.02) c 5? 0.56?(0.02) a 0.64?(0.05) b 0.69?(0.04) c 0.77?(0.03) c 6? 0.60?(0.06) a 0.68?(0.02) b 0.77?(0.03) c 0.83?(0.03) c Mean?(??s.d.)? 0.56?(0.03) a 0.64?(0.05) b 0.73?(0.07) c 0.77?(0.04) c Means? (?? s.d.)? within? the? same? row? followed? by? different? letters? are? significantly?different?at?P?0.05.??? Table? 4.21:??Means? (?? s.d.)? for? left? and? right? lateral? and? diagonal? advanced? placements?and?lift?offs?(s)?for?stock?breed?western?pleasure?horses?at?the?right? lead?extended?lope:??left?lateral?=?LF?LH,?right?lateral?=?RF?RH,?left?diagonal?=? RF?LH,?and?right?diagonal?=?LF?RH.??? ? Left? Right? Lateral?Advanced?Placement?(s)? 0.35?(0.07) a? 0.48?(0.05) b? Diagonal?Advanced?Placement?(s)? 0.71?(0.19) a ? 0.38?(0.51) a ? Lateral?Advanced?Lift?off?(s)? 0.58?(0.15) a ? 0.46?(0.05) a ? Diagonal?Advanced?Lift?off?(s)? 0.78?(0.26) a? 0.04?(0.03) b? Means?(??s.d.)?within?the?same?row?followed?by?different?letters?are? significantly?different?at?P?0.05.? ? ? ? ? ? 125 ? During?the?right?lead?extended?lope,?horses?exhibited?eight?different?limb? support?phases:??1)?diagonal?bipedal?(RF?LH),?2)?unipedal?hind?(LH),?3)?lateral? bipedal?hind?(LF?LH),?4)?tripedal?with?two?hindlimbs?(LF?RH?LH),?5)?diagonal? bipedal?(LF?RH),?6)?tripedal?with?two?forelimbs?(RF?LF?RH),?7)?bipedal?fore?(RF? LF),?and?8)?unipedal?fore?(RF)?(Figure?4.20).??However,?some?horses?displayed? alternate? limb? support? strategies? in? place? of? phases? three? and? seven.??Three? horses?exchanged?phase?three,?1.67???0.58?strides?each,?with?bipedal?hind?(RH? LH)?support;?two?horses?exchanged?phase?seven,?2.50???0.0.71?strides?each,?with? lateral? bipedal??(RF?RH)? support.??Tripedal? with? two? hindlimb? (LF?RH?LH)? support?occupied?the?greatest?percent?of?stride?followed?closely?by?tripedal?with? two?forelimbs?(RF?LF?RH),?diagonal?bipedal?(RF?LH),?diagonal?bipedal?(LF?RH),? unipedal?fore?(RF),?unipedal?hind?(LH),?bipedal?fore?(RF?LF),?and?lateral?bipedal? (RF?RH)?(Table?4.22).??There?was?no?period?of?suspension?or?quadrupedal?limb? support?during?the?right?lead?extended?lope.? ? ? ? ? ? ? 126 LH LF RH RF 2 LH LF RH RF 3 1 LH LF RH RF LH LF RH RF 5 LH LF RH RF 6 LH LF RH RF 7 LH LF RH RF 8 RH LH LF 4 RF ? ? ? ? ? ? ? ? Figure?4.20:?Limb?support?phases?of?the?right?lead?extended?lope?as?performed? by?the?stock?breed?western?pleasure?horse.??Each?circle?is?representative?of?a? horse?s?hoof?(LH???left?hind,?LF???left?fore,?RH???right?hind,?RF???right?fore).?? ? ? ? Table?4.22:??Means?(??s.d.)?for?limb?support?phases?as?a?percent?(%)?of?stride?for? stock?breed?western?pleasure?horses?at?the?right?lead?extended?lope.??? Limb?Support?Phase? Percent?of?Stride?(%)? Tripedal?with?two?Hindlimbs?(LF?RH?LH)? 20.52?(3.62)? Tripedal?with?two?Forelimbs?(RF?LF?RH)? 19.59?(2.81)? Diagonal?Bipedal?(RF?LH)? 18.79?(3.72? Diagonal?Bipedal?(LF?RH)? 14.77?(5.01)? Unipedal?Fore?(RF)? 14.37?(2.45)? Unipedal?Hind?(LH)? 7.20?(2.87)? Bipedal?Fore?(LF?RF)? 1.68?(2.01)? Lateral?Bipedal?(RF?RH)*? 1.23?(2.23)? Lateral?Bipedal?(LF?LH)? 1.18?(0.93)? Bipedal?Hind?(LH?RH)*? 0.66?(0.78)? *?indicates?alternate?limb?support?strategies?utilized?by?some?horses? ? ? 127 Vertical?excursion?was?greatest?for?the?head?(0.40???0.05?m)?followed?by? the?croup?(0.32???0.20?m),?trailing?hind?(LH)?coffin?(0.15???0.04?m),?trailing?fore? (LF)?coffin?(0.15???0.02?m),?leading?fore?(RF)?coffin?(0.15???0.03?m),?leading?hind? (RH)?coffin?(0.13???0.03?m),?and?the?withers?(0.12???0.01?m)?during?the?right?lead? extended?lope.??A?statistical?difference?was?found?when?comparing?the?vertical? excursions?of?the?head?to?withers?(P?0.05)?but?not?when?comparing?the?croup?to? head? (P=0.46)? or? withers? to? croup? (P=0.54).??These? significant? differences? in? vertical?excursions?indicate?that?horses?did?not?exhibit?a?balanced?topline?when? performing? the? right? lead? extended? lope? and? do? not? conform? to? the? breed? standard?concerning?gait?performance.? Right lead angular kinematics. Peak? flexion? and? extension? as? well? as? joint? range? of? motion? (ROM)? for? shoulder,?elbow,?carpus,?fore?fetlock,?hip,?stifle,?hock,?and?hind?fetlock?joints?for? the?right?lead?extended?lope?are?shown?in?Table?4.23.??The?greatest?ROM?was? seen?for?the?fetlock?joint?of?all?four?limbs?followed?by?the?right?and?left?carpus? joints;?the?shoulder?joints?exhibited?the?least?ROM.??? 128 Table? 4.23:??Means? (? s.d.) for? peak? flexion? and? extension? joint? angles? (deg)? measured?on?the?flexor?side?of?the?joint?and?range?of?motion?(ROM)?(deg)?for? fore?and?hindlimbs?at?the?right?lead?extended?lope:?right?hind?(RH),?left?hind? (LH),?right?fore?(RF),?and?left?fore?(LF).??? Joint? Peak?Flexion?(deg)? Peak?Extension?(deg)? Joint?ROM?(deg)? Leading?Forelimb?(RF)? ?????Shoulder? 112.60?(9.92)? 122.22?(8.36)? 9.61?(2.07)? ?????Elbow? 85.58?(11.18)? 147.82?(8.66)? 62.24?(3.58)? ?????Carpus? 109.45?(5.32)? 182.38?(2.62)? 72.93?(4.68)? ?????Fetlock? 142.37?(5.69)? 230.50?(10.99)? 88.13?(9.11)? Trailing?Forelimb?(LF)? ?????Shoulder? 106.71?(6.37)? 117.84?(5.83)? 11.13?(1.83)? ?????Elbow? 97.97?(8.087)? 144.23?(7.54)? 46.26?(4.23)? ?????Carpus? 120.00?(4.39)? 183.06?(2.61)? 63.05?(5.41)? ?????Fetlock? 142.69?(7.16)? 235.89?(9.57)? 93.20?(9.89)? Leading?Hindlimb?(RH)? ?????Hip? 100.12?(3.3.6)? 115.73?(4.38)? 15.62?(1.86)? ?????Stifle? 138.70?(7.45)? 178.89?(6.55)? 40.18?(8.28)? ?????Hock? 135.21?(6.00)? 167.51?(3.75)? 32.30?(6.45)? ?????Fetlock? 147.35?(9.88)? 238.63?(9.71)? 91.28?(15.86)? Trailing?Hindlimb?(LH)? ?????Hip? 101.55?(4.22)? 121.20?(2.46)? 19.65?(4.83)? ?????Stifle? 135.25?(4.62)? 168.45?(8.93)? 33.20?(4.61)? ?????Hock? 138.05?(4.78)? 169.04?(4.01)? 30.99?(7.74)? ?????Fetlock? 149.37?(10.16)? 232.06?(8.60)? 82.69?(12.44)? Representative?fore?and?hindlimb?joint?kinematics?for?horses?at?the?right? lead? extended? lope? are? graphically? presented? in? Figures? 4.21? through? 4.24.?? Graphs?were?plotted?from?hoof?contact?to?the?next?contact?of?the?same?hoof?as?a? percent? of? stride? and? represent? joint? flexion? or? extension? during? a? complete? stride;? the? black? vertical? line? indicates? the? initiation? of? swing? phase.??Upward? 129 inclinations? in? graphs? indicate? extension? of? the? joint? while? downward? inclinations?indicate?flexion.??Leading?forelimb?(right?fore)?joint?motion?graphs? indicate? that? stance? phase? occurred? from? 0? ?? 56%? of? stride? during? which? the? elbow? and? carpus? gradually? extended? and? the? fetlock? reached? peak? extension? (Figure? 4.21).???Swing? phase? occurred? from? 57? ?? 100%? of? the? stride? while? the? elbow,?carpus,?and?fetlock?gradually?flexed.??The?shoulder?reached?peak?flexion? at?mid?swing;?peak?flexion?of?the?carpus?occurred?prior?to?peak?flexion?of?the? elbow?and?fetlock?joints.?? Trailing?forelimb?(left?fore)?joint?motion?graphs?indicate?that?stance?phase? occurred?from?0???54%?of?stride?during?which?the?elbow?and?carpus?gradually? extended? and? the? fetlock? reached? peak? extension? (Figure? 4.22).??The? shoulder? reached?peak?flexion?at?mid?stance?and?then?gradually?extended?throughout?the? remainder?of?the?stride.??Swing?phase?occurred?from?55???100%?of?the?stride?while? the? elbow,? carpus,? and? fetlock? gradually? flexed.??Peak? flexion? of? the? carpus? occurred?prior?to?peak?flexion?of?the?elbow?and?fetlock?joints.?? ?? ? 130 Right?Lead?Extended?Lope?Leading?Forelimb?Joint?Motion 80 100 120 140 160 180 200 220 240 260 0% 20% 40% 60% 80% 100% Stride?(%) Angle ? (deg) Shoulder Elbow Carpus Fetlock Figure?4.21:??Representative?leading?forelimb?(right?fore)?motion?graph?of?the? shoulder,?elbow,?carpus,?and?fetlock?joints?(deg)?as?a?percentage?of?stride?(%)? for? one? stride? of? the? right? lead? extended? lope? of? the? stock? breed? western? pleasure?horse.??The?gait?cycle?was?right?fore?hoof?contact?to?the?next?contact?of? the?right?fore?hoof,?and?the?black?vertical?line?indicates?the?initiation?of?swing? phase. 131 Right?Lead?Extended?Lope?Trailing?Forelimb?Joint?Motion 80 100 120 140 160 180 200 220 240 260 0% 20% 40% 60% 80% 100% Stride?(%) Angle ? (deg) Shoulder Elbow Carpus Fetlock Figure?4.22:??Representative?trailing?forelimb?(left?fore)?motion?graph?of?the? shoulder,?elbow,?carpus,?and?fetlock?joints?(deg)?as?a?percentage?of?stride?(%)? for? one? stride? of? the? right? lead? extended? lope? of? the? stock? breed? western? pleasure?horse.??The?gait?cycle?left?fore?hoof?contact?to?the?next?contact?of?the? left?fore?hoof,?and?the?black?vertical?line?indicates?the?initiation?of?swing?phase.? ? ? Leading? hindlimb? (right? hind)? joint? motion? graphs? indicate? that? stance? phase? occurred? from? 0? ?? 45%? of? stride? during? which? the? hip,? stifle,? and? hock? gradually?flexed?(Figure?4.23).??The?hip?reached?peak?flexion?at?mid?stance?and? then?extended?to?reach?peak?extension?at?late?stance;?the?fetlock?reached?peak? extension? at? mid? stance? and? then? flexed? to? reach? peak? flexion? just? after? the? initiation?of?swing?phase.??Swing?phase?occurred?from?46???100%?of?the?stride? with?the?stifle?and?hock?reaching?peak?extension?in?late?swing?and?the?fetlock? gradually?extending?throughout?the?stride.??? 132 Trailing? hindlimb? (left? hind)? joint? motion? graphs? indicate? that? stance? phase?occurred?from?0???39%?of?stride?during?which?the?stifle?and?hock?gradually? flexed?and?the?hip?gradually?extended?(Figure?4.24).??Peak?flexion?during?stance? phase?of?the?stifle?and?hock?occurred?in?early?stance;?the?fetlock?reached?peak? extension?during?mid?stance?phase.??Swing?phase?occurred?from?40???100%?of?the? stride? while? the? stifle,? hock,?and?fetlock?gradually?flexed.??Peak?flexion?of?the? fetlock?occurred?prior?to?peak?flexion?of?the?stifle?and?hock?joints.? Right?Lead?Extended?Lope?Leading?Hindlimb?Joint?Motion 80 100 120 140 160 180 200 220 240 260 0% 20% 40% 60% 80% 100% Stride?(%) Angle ? (deg) Hip Stifle Hock Fetlock Figure?4.23:??Representative?leading?hindlimb?(right?hind)?motion?graph?of?the? hip,?stifle,?hock,?and?fetlock?joints?(deg)?as?a?percentage?of?stride?(%)?for?one? stride? of? the? right? lead? extended? lope? of? the? stock? breed? western? pleasure? horse.??The?gait?cycle?right?hind?hoof?contact?to?the?next?contact?of?the?right? hind?hoof,?and?the?black?vertical?line?indicates?the?initiation?of?swing?phase.? ? ? 133 Right?Lead?Extended?Lope?Trailing?Hindlimb?Joint?Motion 80 100 120 140 160 180 200 220 240 260 0% 20% 40% 60% 80% 100% Stride?(%) Angle ? (deg) Hip Stifle Hock Fetlock Figure?4.24:??Representative?trailing?hindlimb?(left?hind)?motion?graph?of?the? hip,?stifle,?hock,?and?fetlock?joints?(deg)?as?a?percentage?of?stride?(%)?for?one? stride? of? the? right? lead? extended? lope? of? the? stock? breed? western? pleasure? horse.??The?gait?cycle?was?left?hind?hoof?contact?to?the?next?contact?of?the?left? hind?hoof,?and?the?black?vertical?line?indicates?the?initiation?of?swing?phase.? ? ? Left?lead?temporal?and?linear?kinematics.? Horses? performed? the? left? lead? extended? lope? with? left? limbs? on? the? leading?side?of?the?body?and?right?limbs?on?the?trailing?side;?in?accordance?with? past? stock? breed? western? pleasure? research? (Nicodemus? and? Booker? 2007;? Nicodemus?and?Clayton?2001a),?the?left?lead?collected?lope?(n=6)?had?a?lateral? footfall?sequence?of?trailing?hind?(right?hind)?followed?by?trailing?fore?(right?fore)? and?leading?hind?(left?hind),?working?as?a?diagonal?pair,?followed?by?the?leading? forelimb? (left? fore)? (Figure? 4.25).??Disuniting? of? the? diagonal? pair? was? seen? in? 134 LH LF RH RF 3 LH LF RH RF 1 LH LF RH RF 4 LH LF RH RF 2 72.22%?of?strides?with?84.62%?of?those?strides?showing?a?lateral?footfall?sequence? as? the? trailing? forelimb? (right? fore)? made? contact? with? the? ground? an? instant? before?the?leading?hindlimb?(left?hind).??Disuniting?of?the?diagonal?pair?gave?the? lope?a?four?beat?rhythm,?which?does?not?conform?to?the?breed?standard?for?gait? performance.??Horses?performed?the?left?lead?extended?lope?with?a?mean?stride? length?of?1.70???0.21?m,?stride?duration?of?1.33???0.08?s,?stride?frequency?of?0.76??? 0.05?stride/s,?and?velocity?of?1.28???0.19?m/s.??No?statistically?significant?difference? was? found? between? stride? length? (P=0.07),? duration? (P=0.40),? or? frequency? (P=0.45)? when? calculated? from? consecutive? right? hind? placements? than? when? calculated?from?consecutive?left?hind?placements.??Hind?step?length?was?0.96???? 0.18?m?and?fore?step?length?was?0.91???0.29?m,?with?hind?step?length?making?up? only?a?slightly?greater?percent?of?the?stride?than?fore?step?length.? ? ? Figure? 4.25:? Lateral? footfall? sequence? of? the? left? lead? extended? lope? as? performed? by? the? stock? breed? western? pleasure? horse.??Each? circle? is? representative?of?a?horse?s?hoof?(LH???left?hind,?LF???left?fore,?RH???right?hind,? RF???right?fore).? ? 135 Statistical?significance?was?found?between?the?stance?and?swing?durations? of? the? left? and? right? hind? (P?0.05),? and? interestingly,? the? only? swing? duration? comparison? not?yielding?statistical?significance?(P=0.09)?was?between?the?right? and?left?fore?limbs?(Table?4.24?&?4.25).??Statistical?significance?was?found?between? left?and?right?diagonal?advanced?placements?and?lift?offs?(P?0.05)?(Table?4.26).?? Significant?differences?observed?between?left?and?right?variables?of?hind?stance? and?swing?durations?and?diagonal?advanced?placements?and?lift?offs?indicated? that? the? lope? was? asymmetrical? as? dictated? by? both? scientific? and? breed? definitions.? ? Table?4.24:??Means?(??s.d.)?for?stance?durations?(s)?for?the?following?limbs?of? each?stock?breed?western?pleasure?horse?(Subject?1?6)?at?the?left?lead?extended? lope:?right?hind?(RH)?and?left?hind?(LH).?? ? Means? (?? s.d.)? within? the? same? row? followed? by? different? letters? are? significantly?different?at?P?0.05.? ? ? ? ? ? ? ? Subject? RH?(s) ? LH?(s) ? 1? 0.63?(0.03) a 0.78?(0.20) b 2? 0.78?(0.05) a 0.83?(0.06) b 3? 0.68?(0.02) a 0.74?(0.02) b 4? 0.63?(0.03) a 0.67?(0.00) b 5? 0.63?(0.00) a 0.72?(0.02) b 6? 0.74?(0.04) a 0.77?(0.00) b Mean?(??s.d.) 0.68?(0.06) a 0.75?(0.06) b 136 ? ? ? Table?4.25:??Means?(??s.d.)?for?swing?durations?(s)?for?the?following?limbs?of? each?stock?breed?western?pleasure?horse?(Subject?1?6)?at?the?left?lead?extended? lope:?right?hind?(RH),?left?hind?(LH),?right?fore?(RF),?and?left?fore?(LF).??? Subject? RH?(s) ? LH?(s) ? RF?(s) ? LF?(s) ? 1? 0.77?(0.00) a 0.58?(0.08) b 0.79?(0.02) c 0.79?(0.05) ac 2? 0.68?(0.04) a 0.60?(0.00) b 0.77?(0.12) c 0.79?(0.02) ac 3? 0.58?(0.05) a 0.49?(0.02) b 0.77?(0.03) c 0.72?(0.04) ac 4? 0.62?(0.02) a 0.61?(0.02) b 0.74?(0.02) c 0.71?(0.02) ac 5? 0.64?(0.02) a 0.57?(0.00) b 0.73?(0.00) c 0.67?(0.03) ac 6? 0.59?(0.02) a 0.57?(0.00) b 0.82?(0.02) c 0.78?(0.02) ac Mean?(??s.d.)? 0.65?(0.07) a 0.57?(0.04) b 0.77?(0.03) c 0.74?(0.05) ac Means? (?? s.d.)? within? the? same? row? followed? by? different? letters? are? significantly?different?at?P?0.05.? Table? 4.26:??Means? (?? s.d.)? for? left? and? right? lateral? and? diagonal? advanced? placements?and?lift?offs?(s)?for?stock?breed?western?pleasure?horses?at?the?left? lead?extended?lope:??left?lateral?=?LF?LH,?right?lateral?=?RF?RH,?left?diagonal?=? RF?LH,?and?right?diagonal?=?LF?RH.??? ?? Left? Right? Lateral?Advanced?Placement?(s)? 0.47?(0.05) a ? 0.43?(0.26) a ? Diagonal?Advanced?Placement?(s)? 0.12?(0.20) a? 0.85?(0.12) b? Lateral?Advanced?Lift?off?(s)? 0.48?(0.08) a ? 0.45?(0.06) a ? Diagonal?Advanced?Lift?off?(s)? 0.03?(0.01) a? 0.87?(0.10) b? Means? (?? s.d.)? within? the? same? row? followed? by? different? letters? are? significantly?different?at?P?0.05.??? ? ? ? ? ? 137 During?the?left?lead?extended?lope,?horses?exhibited?eight?different?limb? support?phases:??1)?diagonal?bipedal?(LF?RH),?2)?unipedal?hind?(RH),?3)?lateral? bipedal? (RF?RH),? 4)? tripedal? with? two? hindlimbs? (RF?RH?LH),? 5)? diagonal? bipedal?(RF?LH),?6)?tripedal?with?two?forelimbs?(RF?LF?LH),?7)?bipedal?fore?(LF? RF),? and? 8)? unipedal? fore? (LF)? (Figure? 4.26).??However,? some? horses? chose? to? display?alternate?limb?support?strategies?in?place?of?phases?three?and?seven.??Two? horses?exchanged?phase?three?(1.5???0.71?strides?each)?with?bipedal?hind?(RH?LH)? support;?three?horses?exchanged?phase?seven,?1.67???0.58?strides?each,?with?lateral? bipedal? (LF?LH)? support.??Tripedal? with? two? hindlimbs? (RF?RH?LH)? support? occupied? the? greatest? percent? of? stride? followed? closely? by? tripedal? with? two? forelimbs? (LF?RF?LH),? diagonal? bipedal? (LF?RH),? unipedal? fore? (LF),? diagonal? bipedal?(RF?LH),?unipedal?hind?(RH),?right?lateral?bipedal?(RF?RH),?and?bipedal? fore?(RF?LF)?(Table?4.27).??There?was?no?period?of?suspension?or?quadrupedal? limb?support?during?the?left?lead?extended?lope.??? ? ? ? ? ? ? ? ? ? ? ? ? 138 LH LF RH RF 1 LH LF RH RF 2 LH LF RH RF 3 LH LF 4 LH LF RH RF 5 LH LF RH RF 6 LH LF RH RF 7 LH LF RH RF 8 ? ? ? ? ? ? Figure?4.26:?Limb?support?phases?of?the?left?lead?extended?lope?as?performed? by?the?stock?breed?western?pleasure?horse.??Each?circle?is?representative?of?a? horse?s?hoof?(LH???left?hind,?LF???left?fore,?RH???right?hind,?RF???right?fore).??? Table?4.27:??Means?(??s.d.)?for?limb?support?phases?as?a?percent?(%)?of?stride?for? stock?breed?western?pleasure?horses?at?the?left?lead?extended?lope.??? Limb?Support?Phase? Percent?of?Stride?(%)? Tripedal?with?two?Hindlimbs?(RF?RH?LH)? 22.69?(3.49)? Tripedal?with?two?Forelimbs?(RF?LF?LH)? 20.33?(3.09)? Diagonal?Bipedal?(LF?RH)? 19.60?(4.94)? Unipedal?Fore?(LF)? 13.80?(4.56)? Diagonal?Bipedal?(RF?LH)? 12.40?(4.77)? Unipedal?Hind?(RH)? 6.32?(3.31)? Lateral?Bipedal?(RF?RH)? 2.12?(1.36)? Bipedal?Fore?(LF?RF)? 1.14?(1.48)? Lateral?Bipedal?(LF?LH)*? 0.92?(1.14)? Bipedal?Hind?(LH?RH)*? 0.68?(0.07)? *?indicates?alternate?limb?support?strategies?utilized?by?some?horses? ? 139 Vertical?excursion?was?greatest?for?the?croup?(0.45???0.06?m)?followed?by? the?head?(0.38???0.09?m),?trailing?fore?(RF)?coffin?(0.18???0.03?m),?leading?hind? (LH)?(0.18???0.04?m),?leading?fore?(LF)?coffin?(0.13???0.02?m),?withers?(0.13???0.01? m),?and?trailing?hind?(RH)?coffin?(0.13???0.02?m)?during?the?left?lead?extended? lope.? A? statistical? difference? (P?0.05)? was? found? when? comparing? the? vertical? excursions?of?the?head?to?withers?and?withers?to?croup;?a?statistical?difference? was?not?found?when?comparing?the?head?to?croup?(P=0.06).??These?significant? differences?in?vertical?excursions?indicate?that?horses?did?not?exhibit?a?balanced? topline?when?performing?the?left?lead?extended?lope?and?do?not?conform?to?the? breed?standard?concerning?gait?performance.? ? Left?lead?angular?kinematics.? ?? Peak? flexion? and? extension? as? well? as? joint? ROM? for? shoulder,? elbow,? carpus,? fore? fetlock,? hip,? stifle,? hock,? and? hind? fetlock? joints? for? the? left? lead? extended? lope? are? shown? in? Table? 4.28.??The? greatest? ROM? was? seen? for? the? fetlock? joint? of? all? four? limbs? followed? by? the? right? and? left? carpus? joints;? the? shoulder?joints?exhibited?the?least?ROM.??? ? ? ? 140 Table? 4.28:??Means? (?? s.d.)? for? peak? flexion? and? extension? joint? angles? (deg)? measured?on?the?flexor?side?of?the?joint?and?range?of?motion?(ROM)?(deg)?for? fore? and? hindlimbs? at? the? left? lead? extended? lope:? right? hind? (RH),? left? hind? (LH),?right?fore?(RF),?and?left?fore?(LF).??? Joint? Peak?Flexion?(deg)? Peak?Extension?(deg)? Joint?ROM?(deg)? Leading?Forelimb?(LF)? ?????Shoulder? 110.04?(5.00)? 118.94?(5.70)? 8.90?(1.63)? ?????Elbow? 87.50?(9.49)? 145.89?(6.45)? 58.38?(4.47)? ?????Carpus? 112.23?(5.07)? 182.70?(2.89)? 70.48?(4.17)? ?????Fetlock? 142.89?(4.58)? 227.60?(9.92)? 84.71?(9.12)? Trailing?Forelimb?(RF)? ?????Shoulder? 108.29?(8.50)? 119.17?(9.64)? 10.87?(3.67)? ?????Elbow? 97.12?(8.59)? 145.24?(9.53)? 48.12?(6.15)? ?????Carpus? 119.39?(4.27)? 182.15?(3.36)? 62.76?(5.49)? ?????Fetlock? 143.33?(5.78)? 235.02?(10.56)? 91.69?(9.84)? Leading?Hindlimb?(LH)? ?????Hip? 99.98?(2.87)? 113.71?(3.63)? 13.73?(1.86)? ?????Stifle? 141.65?(6.27)? 177.63?(9.95)? 35.98?(4.58)? ?????Hock? 141.41?(3.32)? 168.78?(3.57)? 27.37?(4.21)? ?????Fetlock? 149.17?(7.45)? 234.01?(6.41)? 84.84?(10.70)? Trailing?Hindlimb?(RH)? ?????Hip? 103.61?(4.28)? 124.47?(5.74)? 20.86?(2.27)? ?????Stifle? 134.49?(6.09)? 164.90?(4.98)? 30.41?(4.19)? ?????Hock? 136.47?(5.03)? 167.06?(5.53)? 30.59?(5.77)? ?????Fetlock? 156.98?(7.09)? 237.12?(11.92)? 80.14?(14.36)? Representative?fore?and?hindlimb?joint?kinematics?for?horses?during?the? left?lead?extended?lope?are?graphically?presented?in?Figures?4.27?through?4.30.?? Graphs?were?plotted?from?hoof?contact?to?the?next?contact?of?the?same?hoof?as?a? percent? of? stride? and? represent? joint? flexion? or? extension? during? a? complete? stride;? the? black? vertical? line? indicates? the? initiation? of? swing? phase.??Upward? inclinations? in? graphs? indicate? extension? of? the? joint? while? downward? 141 inclinations? indicate? flexion.??Leading? forelimb? (left? fore)? joint? motion? graphs? indicate? that? stance? phase? occurred? from? 0? ?? 55%? of? stride? during? which? the? elbow? and? carpus? gradually? extended? and? the? fetlock? reached? peak? extension? (Figure?4.27).??The?shoulder?gradually?flexed?throughout?the?stance?phase.??Swing? phase?occurred?from?56???100%?of?the?stride?while?the?elbow,?carpus,?and?fetlock? gradually?flexed.??Peak?flexion?of?the?carpus?occurred?prior?to?peak?flexion?of?the? elbow?and?fetlock?joints;?peak?extension?of?the?shoulder?occurred?in?early?swing.? Trailing? forelimb? (right? fore)? joint? motion? graphs? indicate? that? stance? phase? occurred? from? 0? ?? 54%? of? stride? during? which? the? elbow? and? carpus? gradually?extended?and?the?fetlock?reached?peak?extension?(Figure?4.28).??The? shoulder?reached?peak?flexion?at?20%?of?stride?and?then?extended?throughout?the? stride.??Swing? phase? occurred? from? 55? ?? 100%? of? the? stride? while? the? elbow,? carpus,?and?fetlock?gradually?flexed.??Peak?flexion?of?the?carpus?occurred?prior?to? peak?flexion?of?the?elbow?and?fetlock?joints.?? 142 Left?Lead?Extended?Lope?Leading?Forelimb?Joint?Motion 60 80 100 120 140 160 180 200 220 240 260 0% 20% 40% 60% 80% 100% Stride?(%) Angle ? (deg) Shoulder Elbow Carpus Fetlock Figure?4.27:??Representative?leading?forelimb?(left?fore)?motion?graph?of?the? shoulder,?elbow,?carpus,?and?fetlock?joints?(deg)?as?a?percentage?of?stride?(%)? for?one?stride?of?the?left?lead?extended?lope?of?the?stock?breed?western?pleasure? horse.??The?gait?cycle?was?left?fore?hoof?contact?to?the?next?contact?of?the?left? fore?hoof,?and?the?black?vertical?line?indicates?the?initiation?of?swing?phase.??? ? ? ? ? ? ? ? 143 Left?Lead?Extended?Lope?Trailing?Forelimb?Joint?Motion 60 80 100 120 140 160 180 200 220 240 260 0% 20% 40% 60% 80% 100% Stride?(%) Angle ? (deg) Shoulder Elbow Carpus Fetlock Figure?4.28:??Representative?trailing?forelimb?(right?fore)?motion?graph?of?the? shoulder,?elbow,?carpus,?and?fetlock?joints?(deg)?as?a?percentage?of?stride?(%)? for?one?stride?of?the?left?lead?extended?lope?of?the?stock?breed?western?pleasure? horse.??The?gait?cycle?was?right?fore?hoof?contact?to?the?next?contact?of?the?right? fore?hoof,?and?the?black?vertical?line?indicates?the?initiation?of?swing?phase.??? ? ? Leading? hindlimb? (left? hind)? joint? motion? graphs? indicate? that? stance? phase? occurred? from? 0? ?? 45%? of? stride? during? which? the? hip,? stifle,? and? hock? gradually? flexed? and? then? extended? (Figure? 4.29).??The? hip? reached? peak? extension?in?late?stance?and?then?gradually?flexed?throughout?swing?phase;?the? fetlock? reached? peak? extension? at? mid? stance? and? then? flexed? to? reach? peak? flexion?at?early?swing.??Swing?phase?occurred?from?46???100%?of?the?stride?with? the? stifle? and? hock? reaching? peak? flexion? at? mid? swing? and? then? gradually? extending?throughout?the?stride.? 144 Trailing? hindlimb? (right? hind)? joint? motion? graphs? indicate? that? stance? phase?occurred?from?0???41%?of?stride?during?which?the?stifle?and?hock?gradually? flexed?and?then?extended,?and?the?fetlock?reached?peak?extension?(Figure?4.30).?? The? hip? reached? peak? extension? at? 23%? of? stride? and? then? gradually? flexed? throughout?the?stride.??Swing?phase?occurred?from?42???100%?of?the?stride?while? the?stifle,?hock,?and?fetlock?gradually?flexed.??Peak?flexion?of?the?fetlock?occurred? prior?to?peak?flexion?of?the?stifle?and?hock?joints.?? Left?Lead?Extended?Lope?Leading?Hindlimb?Joint?Motion 60 80 100 120 140 160 180 200 220 240 260 0% 20% 40% 60% 80% 100% Stride?(%) Angle ? (deg) Hip Stifle Hock Fetlock Figure?4.29:??Representative?leading?hindlimb?(left?hind)?motion?graph?of?the? hip,?stifle,?hock,?and?fetlock?joints?(deg)?as?a?percentage?of?stride?(%)?for?one? stride?of?the?left?lead?extended?lope?of?the?stock?breed?western?pleasure?horse.?? The?gait?cycle?was?left?hind?hoof?contact?to?the?next?contact?of?the?left?hind? hoof,?and?the?black?vertical?line?indicates?the?initiation?of?swing?phase.? 145 Left?Lead?Extended?Lope?Trailing?Hindlimb?Joint?Motion 60 80 100 120 140 160 180 200 220 240 260 0% 20% 40% 60% 80% 100% Stride?(%) Angle ? (deg) Hip Stifle Hock Fetlock Figure?4.30:??Representative?trailing?hindlimb?(right?hind)?motion?graph?of?the? hip,?stifle,?hock,?and?fetlock?joints?(deg)?as?a?percentage?of?stride?(%)?for?one? stride?of?the?left?lead?extended?lope?of?the?stock?breed?western?pleasure?horse.?? The?gait?cycle?was?right?hind?hoof?contact?to?the?next?contact?of?the?right?hind? hoof,?and?the?black?vertical?line?indicates?the?initiation?of?swing?phase.??? ? ? ? Collected?versus?Extended?Lope? ? Right?lead?temporal?and?linear?kinematics.? ? Horses? performed? the? right? lead? collected? lope? with? a? diagonal? footfall? sequence?and?the?right?lead?extended?lope?with?a?lateral?footfall?sequence?(Figure? 4.7?&?4.19).??The?diagonal?footfall?sequence?found?in?the?collected?lope?was?due?to? 61.54%? of? the? disunited? strides? yielding? a? right? hind? contact? prior? to? left? fore? contact;? the? lateral? footfall? sequence? found? in? the? extended? lope? was? due? to? 146 57.14%? of? the? disunited? strides? yielding? a? left? fore? contact? prior? to? right? hind? contact.??These?differences?in?footfalls?were?related?to?variations?in?limb?support? strategies?for?phases?three?and?seven?between?the?collected?and?extended?right? lead?lope?(Figure?4.8?&?4.20).????Limb?support?phase?three?consisted?of?bipedal? hind? (RH?LH)? during? the? collected? lope? and? of? left? lateral? bipedal? (LF?LH)? during? the? extended? lope? while? phase? seven? consisted? of? right? lateral? bipedal? (RF?RH)?during?the?collected?lope?and?bipedal?fore?(LF?RF)?during?the?extended? lope.??Due?to?the?large?number?of?variables?analyzed?and?the?relatively?small? sample? size,? there? were? insufficient? residual? degrees? of? freedom? to? perform? a? multivariate?ANOVA?for?either?the?temporal?or?linear?variables?of?the?right?lead? collected? and? extended? lope.??Therefore,? the? univariate? results? are? presented? cautiously? and? with? the? understanding? of? the? risk? of? type? 1? errors? being? increased? due? to? the? number? of? comparisons? being? performed.??Although? a? significance?level?of?95%?was?chosen?for?statistical?comparisons,?all?variables?that? were? deemed? significant? had? a? univariate? P? value? less? than? or? equal? to? 0.04.?? Therefore,? the? risk? of? type? 1? errors? is? acceptably? small,? even? considering? the? number?of?comparisons?being?performed.??? Stride?length?was?longer?for?the?right?lead?extended?lope?and?indicated? statistical? significance? (P?0.05)? from? the? right? lead? collected? lope? (Table? 4.29).?? Horses? also? performed? the? right? lead? extended? lope? with? a? velocity? that? was? 147 statistically?significant?(P?0.05)?from?the?velocity?of?the?right?lead?collected?lope.?? As? well,? vertical? excursion? of? the? withers? indicated? statistical? significance? (P?0.05).??The? display?of?greater?vertical?excursion?at?the?withers?when?at?the? extended? lope? than? when? performing? the? collected? lope? indicates? that? the? extended?lope?exhibited?greater?lift?in?the?forelimbs?than?did?the?collected?lope.?? Diagonal?advanced?placement?as?well?as?several?limb?support?phases?indicated? temporal?statistical?significance?(P?0.05)?when?compared?between?the?collected? and?extended?lope.??Interestingly,?the?shorter?time?seen?for?diagonal?advanced? placement? between? the? right? fore? and? left? hind? limbs? when? performing? the? extended? than? when? performing? the? collected? lope? indicates? that? leading? forelimb?and?trailing?hindlimb?moved?more?closely?together?in?time?during?the? extended?lope?than?in?the?collected?lope.?? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? 148 Table?4.29:??Statistically?significant?(P?0.05)?means?(??s.d.)?for?stride?length?(m),? velocity? (m/s),? vertical? excursion? of? the? withers? (m),? diagonal? advanced? placement?of?the?right?fore?to?left?hind?(s),?and?limb?support?phases?of?tripedal? with?two?forelimbs,?diagonal?bipedal,?and?unipedal?fore?for?stock?breed?western? pleasure?horses?at?the?right?lead?collected?and?extended?lope?(LH???left?hind,?LF??? left?fore,?RH???right?hind,?RF???right?fore).??? ? Collected? Lope ? Extended? Lope ? Stride?Length?(m)? 1.57?(0.08) ? 1.68?(0.06)? Velocity?(m/s)? 1.16?(0.06)? 1.28?(0.05)? Vertical?Excursion?of?the?Withers?(m)? 0.12?(0.01)? 0.13?(0.01)? Diagonal?Advanced?Placement?(RF?LH)?(s)? 0.82?(0.06)? 0.71?(0.08)? Limb?Support?Phases?(%)? ?????Tripedal?with?two?Forelimbs?(RF?LF?RH)? 22.14?(0.84)? 19.59?(1.15)? ?????Diagonal?Bipedal?(LF?RH)? 22.35?(1.39)? 18.79?(1.52)? ?????Diagonal?Bipedal?(RF?LH)? 11.74?(1.99)? 14.77?(2.05)? ?????Unipedal?Fore?(RF)? 9.20?(0.89)? 14.37?(1.00)? ? ? Right?lead?angular?kinematics.? Due? to? the? large?number?of?variables?analyzed?and?the?relatively?small? sample? size,? there? were? insufficient? residual? degrees? of? freedom? to? perform? a? multivariate?ANOVA?for?the?angular?variables.??Therefore,?the?univariate?results? are?presented?cautiously?and?with?the?understanding?of?the?risk?of?type?1?errors? being? increased? due? to? the? number? of? comparisons? being? performed.??A? significance? level? of? 95%? was? chosen? for? statistical? comparisons;? however,? no? angular?variables?indicated?statistical?significance?when?compared?between?the? collected?and?extended?right?lead?lope.??Motion?graphs?indicated?the?same?trends? 149 in?joint?motion?between?the?collected?and?extended?right?lead?lope?(Figures?4.9??? 4.12?and?4.21???4.24).??? Left?lead?temporal?and?linear?kinematics. Horses?performed?the?left?lead?collected?and?extended?lope?with?a?lateral? footfall?sequence?(Figures?4.13?&?4.25);?however,?horses?approached?the?two?gaits? with?variations?in?limb?support?strategies?for?phase?seven,?but?not?with?phase? three,? between? the? collected? and? extended? left? lead? lope? (Figure? 4.14? &? 4.26).???? Phase?seven?consisted?of?left?lateral?bipedal?(LF?LH)?during?the?collected?lope? and?bipedal?fore?(LF?RF)?during?the?extended?lope.??Due?to?the?large?number?of? variables?analyzed?and?the?relatively?small?sample?size,?there?were?insufficient? residual? degrees? of? freedom? to? perform? a? multivariate? ANOVA? for? either? the? temporal? or? linear? variables? of? the? left? lead? collected? and? extended? lope.?? Therefore,? the? univariate? results? are? presented? cautiously? and? with? the? understanding?of?the?risk?of?type?1?errors?being?increased?due?to?the?number?of? comparisons?being?performed.??Although?a?significance?level?of?95%?was?chosen? for? statistical? comparisons,? all? variables? that? were? deemed? significant? had? a? univariate?P?value?less?than?or?equal?to?0.04.??Therefore,?the?risk?of?type?1?errors?is? acceptably?small,?even?considering?the?number?of?comparisons?being?performed.??? Stride? length? was? longer? for? the? left? lead? extended? lope? and? indicated? significant?statistical?significance?(P?0.05)?from?the?left?lead?collected?lope?(Table? 150 4.30).??Horses?also?performed?the?left?lead?extended?lope?with?a?velocity?that?was? statistically?significant?(P?0.05)?from?the?velocity?of?the?left?lead?collected?lope.?? Stride?duration?as?well?as?diagonal?advanced?lift?offs,?lateral?advanced?lift?offs,? and? unipedal? left? fore? limb? support? phase? indicated? temporal? statistical? significance?(P?0.05)?when?compared?between?the?collected?and?extended?lope.?? Interestingly,? the? shorter? time? seen? for? diagonal? and? lateral? advanced? lift?offs? between? the? fore? and? hindlimbs? when? performing? the? extended? than? when? performing?the?collected?lope?indicates?that?they?moved?more?closely?together?in? time?during?the?extended?lope?than?in?the?collected?lope.??? ? Table?4.30:??Statistically?significant?(P?0.05)?means?(??s.d.)?for?stride?length?(m),? velocity? (m/s),? stride? duration? (s),? diagonal? advanced? lift?offs? (s),? lateral? advanced? lift?off? (s),? and? unipedal? fore? limb? support? for? stock? breed? western? pleasure?horses?at?the?left?lead?collected?and?extended?lope?(LH???left?hind,?LF??? left?fore,?RH???right?hind,?RF???right?fore).??? ? Collected? Lope ? Extended? Lope ? Stride?Length?(m)? 1.50?(0.07)? 1.69?(0.08)? Velocity?(m/s)? 1.09?(0.05)? 1.28?(0.08)? Stride?Duration?(s)? 1.39?(0.03)? 1.33?(0.03)? Diagonal?Advanced?Lift?off?(RF?LH)?(s)? 0.76?(0.09)? 0.03?(0.01)? Diagonal?Advanced?Lift?off?(LF?RH)?(s)? 0.17?(0.09)? 0.87?(0.04)? Lateral?Advanced?Lift?off?(RF?RH)?(s)? 0.55?(0.05)? 0.45?(0.03)? Unipedal?Fore?Limb?Support?(LF)? 10.00?(1.54)? 13.80?(1.86)? ? 151 Left?lead?angular?kinematics.? Due? to? the? large?number?of?variables?analyzed?and?the?relatively?small? sample? size,? there? were? insufficient? residual? degrees? of? freedom? to? perform? a? multivariate?ANOVA?for?the?angular?variables.??Therefore,?the?univariate?results? are?presented?cautiously?and?with?the?understanding?of?the?risk?of?type?1?errors? being? increased? due? to? the? number? of? comparisons? being? performed.??A? significance?level?of?95%?was?chosen?for?statistical?comparisons,?all?variables?that? were? deemed? significant? had? a? univariate? P? value? less? than? or? equal? to? 0.04.?? Therefore,?the?risk?of?type?1?errors?is?rather?small,?even?considering?the?number? of? comparisons? being? performed.??Angular? variables? indicating? statistical? significance?(P?0.05)?between?the?collected?and?extended?left?lead?lope?include? hip? ROM,? stifle? ROM,? peak? hock? flexion,? and? hock? ROM? (Table? 4.31).?? Differences? in? these? joints? seem? to? indicate? that? the? distinction? between? the? collected?and?extended?left?lead?lope?are?most?likely?due?to?variation?in?hindlimb? kinematics.??Motion?graphs?indicated?the?same?trends?in?joint?motion?between? the?collected?and?extended?left?lead?lope?(Figures?4.15???4.18?and?4.27???4.30).??? ? ? ? ? ? 152 Table?4.31:??Statistically?significant?(P?0.05)?means?(??s.d.)?for?angular?variables? (deg)?of?peak?flexion,?peak?extension,?and?range?of?motion?(ROM)?for?stock?breed? western?pleasure?horses?at?the?collected?and?extended?left?lead?lope.??? ? Collected?Lope ? Extended?Lope ? Hip?ROM? 18.96?(1.17)? 20.86?(0.93)? Stifle?ROM? 33.12?(1.40)? 30.41?(1.71)? Hock? ?????Peak?Flexion? 131.80?(2.61)? 136.47?(2.01)? ?????ROM? 35.43?(2.23)? 30.59?(2.35)? ? 153 Chapter?V? ? Discussion? ? ? ? The? purpose? of? this? study? was? to? collect? temporal,? linear,? and? angular? kinematics?of?the?stock?breed?western?pleasure?horse?in?order?to?compare?the? variables?of?the?collected?and?extended?jog?and?the?collected?and?extended?lope? to? determine? consistency? with? current? rulebooks? of? major? stock? breed? associations.??Additionally,?this?study?sought?to?determine?if?the?extended?jog? and? lope? conform? to? a? more? natural? way? of? going? for? stock? breed? western? pleasure?horses,?which?may?reduce?the?risk?of?joint?injury?and?trauma?more?than? does?the?collected?jog?and?lope.??The?current?chapter?presents?the?discussion?on? the? topics? of? a)? collected? and? extended?jog,?b)?collected?and?extended?lope,?c)? injuries,?and?d)?summary.? After?numerous?locomotive?studies,?Hildebrand?(1965)?concluded?that?a? horse?s?locomotion?is?not?only?more?controllable?than?that?of?other?animals?but?is? more? adaptable? and? opportunistic? with? regards? to? limb? support? and? footfall? 154 sequences.??Equids? have? the? innate? ability? to? adapt,? and? in? turn,? exhibit? gait? performance?variations;?this?adaptability,?whether?through?training?or?breeding,? has?resulted?in?the?stock?breed?western?pleasure?horse?s?performance?of?the?jog? and? lope,? which? are? viewed? (perhaps? erroneously)? as? gait? variations? of? the? dressage?horse?s?trot?and?canter,?respectively.???? ? Collected?and?Extended?Jog? ? Hildebrand? (1965)? developed? a? gait? continuum? that? distinguished? between?symmetrical?gaits?based?on?the?temporal?variables?of?percent?(%)?stride? of?advanced?placement?and?hind?stance.??When?plotting?the?previously?studied? stock?breed?western?pleasure?jog?(lateral?advanced?placement???46%;?hind?stance? ??60%)?(Booker?2005;?Nicodemus?and?Booker?2007)?on?Hildebrand?s?continuum,? it?fell?in?the?region?between?the?Arabian?jog?(lateral?advanced?placement???50%;? hind?stance???54%)?and?Quarter?Horse?walk?(lateral?advanced?placement???33%;? hind?stance???66%)?(Figure?5.1)?(Hildebrand?1965;?Nicodemus?and?Booker?2007).?? The? current? study? plots? the? collected? jog? at? 45.20? ?? 5.52%? lateral? advanced? placement? and? 61.02? ?? 5.97%? hind? stance? while? the? extended? jog? is? plotted? at? 50.35???1.39%?lateral?advanced?placement?and?58.75???4.07%?hind?stance?(Figure? 5.1).???Hildebrand?s?two?charts?can?be?overlaid?to?indicate?the?breed?of?horse?and? gait? performed.??In? considering? these? charts,? the? data? from? the? present? study? 155 indicates?that?the?position?of?the?collected?jog?is?still?more?closely?related?to?the? walk?or?an?animated?variation?of?the?slow?trot,?performed?by?the?Arabian?horse,? than? the? trot? and? places? it? within? the? dotted? area? where? Hildebrand? (1965)? indicated?unusual?gaits?with?no?common?name?(Figure?5.2).??Additionally,?while? the?extended?jog?is?plotted?bordering?the?region?that?indicates?unusual?gaits,?it?is? closer?to?the?Arabian?at?the?trot?with?regards?to?lateral?advanced?placement?than? the?collected?jog?(Figure?5.2).??Based?on?positioning?it?is?reasonable?to?conclude? that?stock?breed?western?pleasure?horses?are?not?simply?performing?a?variation?of? the?trot?when?executing?the?collected?and?extended?jog,?but?altogether?separate? gaits?that?have?not?been?appropriately?named?or?classified?(Figure?5.2).? 156 Figure?5.1:??The?graph?in?which?nearly?all?symmetrical?gaits?of?horses?fall? (Hildebrand?1965).??The?blue?filled?circle?indicates?the?Quarter?Horse?while? the? orange? filled? square? indicates? the? Arabian? horse.??The? black? filled? triangle?(partially?hidden)?indicates?the?stock?breed?western?pleasure?jog?as? determined?by?Nicodemus?and?Booker?(2007).??The?yellow?filled?diamond? indicates?the?position?where?the?collected?jog?would?fit?into?the?continuum? while?the?purple?filled?oval?indicates?the?position?where?the?extended?jog? would?fit?into?the?continuum.??? ? ? ? 157 ? Figure?5.2:??The?relationship?between?symmetrical?gaits?of?horses.??Gaits? that? would? fall? within? areas? indicated? by? dotted? lines? are? unusual? and? have?no?common?name?(Hildebrand?1965).??The?blue?filled?circle?indicates? the? Quarter? Horse? while? the? orange? filled? square? indicates? the? Arabian? horse.??The?black?filled?triangle?(partially?hidden)?indicates?the?stock?breed? western? pleasure? jog? as? determined? by? Nicodemus? and? Booker? (2007).?? The?yellow?filled?diamond?indicates?the?position?where?the?collected?jog? would? fit? into? the? continuum? while? the? purple? filled? oval? indicates? the? position?where?the?extended?jog?would?fit?into?the?continuum.? ? ? ? 158 Temporal?and?linear?kinematics.? ???In? the? current? study,? both? the? collected? and? extended? jogs? were? scientifically?determined?to?be?symmetrical?four?beat?stepping?gaits?with?lateral? footfall?sequences?and?no?period?of?suspension.??The?present?findings?related?to? the? collected? jog? are? in? accordance? with? previous? studies? where? the? jog,? synonymous?with?the?current?study?s?collected?jog,?was?found?to?have?four?beats,? a? lateral? footfall? sequence,? and? an? irregular? rhythm? due? to? diagonal? couplets? (Nicodemus?and?Booker?2007;?Nicodemus?and?Clayton?2001a);?the?extended?jog? as?performed?by?the?stock?breed?western?pleasure?horse?has?not?been?studied? previously,?so?no?direct?comparison?can?be?made.??Stride?length?was?longest,?as? expected,? for? the? extended? jog,? however? the? collected? jog? exhibited? a? much? longer?stride?length?than?did?its?counter?part?in?the?Nicodemus?and?Booker?study? (2007)?(Table?5.1).??Further,?the?collected?jog?exhibited?a?longer?stride?duration? than?did?the?extended?jog,?however?both?were?longer?than?those?measured?in? Nicodemus? and? Booker? (2007);? conversely,? stride? frequency? and? velocity? was? smaller?for?the?collected?jog?than?the?extended?jog,?and?both?were?smaller?than? the?Nicodemus?and?Booker?(2007)?jog.??These?findings?indicate?that?current?stock? breed?western?pleasure?horses?are?exhibiting?longer?stride?lengths?and?durations? but?slower?stride?frequencies?and?velocities?than?did?previous?research?on?stock? breed?western?pleasure?horses.??However,?the?relationship?between?stride?length,? 159 stride?duration,?stride?frequency,?and?velocity?indicates?that?the?horse?s?legs?are? covering?more?distance?yet?moving?slower.????The?differences?seen?in?the?above? mentioned?temporal?and?linear?variables?have?resulted?in?a?slower?moving?stock? breed? western? pleasure? horse? could? be? due? to? a? combination? of? breeding? and? training? than? due? to? breed? association? rule? changes? implemented? since? the? previous?research?was?conducted.??Horses?that?cover?more?ground?per?step?yet? move?the?legs?more?slowly?are?more?desirable?in?the?current?stock?breed?western? pleasure? horse? industry? because? the? horse? is? more? closely? following? breed? association? guidelines? with? regards? to? the? collected? and? extended? jog? being? ground?covering?gaits?(APHA?2009;?ApHC?2009b;?AQHA?2009;?PHBA?2008).? Diagonal? advanced? placements? and? lift?offs? indicate? that? both? the? collected?and?extended?gaits?were?performed?with?diagonal?couplets?instead?of? diagonal?pairs?indicating?that?while?the?diagonal?limbs?moved?in?concert,?they? did?not?move?synchronously?(Table?5.1).??The?greatest?time?between?placement? and? lift?off? of? the? diagonal? pairs? was? seen? at? the? collected? jog? and? indicates? ?poorer??gait?performance?than?was?seen?in?the?Nicodemus?and?Booker?(2007)? jog;? however,? the? extended? jog? indicated? greater? synchronization? of? diagonal? pairs? than? the? collected? jog.??The? substantial? percentage? of? stride? spent? in? diagonal?bipedal?limb?support?during?the?collected?and?extended?jog?gave?both? gaits?a?trot?like?appearance?and?provides?the?basis?for?the?classification?by?the? 160 breed?association?for?the?jog?to?be?considered?a?variation?of?the?trot?(Table?5.1).?? Further? inspection? of? limb? support? phases? indicates? that? the? jog? previously? studied?by?Nicodemus?and?Booker?(2007)?consisted?of?a?percentage?of?stride?in? quadrupedal,? tripedal? with? two? forelimbs,? and? tripedal? with? two? hindlimbs? similar? to? those? of? the? collected? and? extended? jog? in? the? present? study.?? Differences?seen?in?limb?support?percentages?between?the?present,?Nicodemus? and?Booker?(2007),?and?Nicodemus?and?Clayton?(2001a)?studies?are?most?likely? due?to?the?speed?at?which?the?gaits?were?performed;?however,?it?should?be?noted? that? while? gait? velocity? was? measured? in? the? current? study,? it? was? not? a? controlled?variable?because?western?pleasure?gait?definitions?set?forth?by?stock? breed?associations?do?not?indicate?a?standard?with?regards?to?speed.???? Comparisons?regarding?vertical?excursions?of?the?head?and?croup?do?not? indicate?differences?between?the?jog,?collected?jog,?and?extended?jog?(Table?5.1).?? Vertical? excursions? of? the? coffin? suggest? that? current? stock? breed? western? pleasure?horses?do?not?pick?their?hooves?up?as?high?as?past?stock?breed?western? pleasure?horses?(Table?5.1)?(Nicodemus?and?Booker?2007).??? ? ? ? 161 Table?5.1:??Means?(??s.d.)?for?temporal?and?linear?variables?of?the?collected?and? extended?jog?for?the?present?study?and?the?jog?from?the?Nicodemus?and?Clayton? (2001a)? as? well? as? the? Nicodemus? and? Booker? study? (2007).??NP? indicates? temporal?or?linear?variables?that?were?not?present?in?the?Nicodemus?and?Clayton? (2001a)?study.? ? Jog?? (2001a)? Jog?? (2007)? Collected? Jog? Extended? Jog? Stride?Length?(m)? NP? 1.01?(0.1)? 1.28?(0.17)? 1.42?(0.16)? Stride?Duration?(s)? 0.95?(0.04)? 0.92?(0.03)? 1.91?(0.12)? 1.75?(0.08)? Stride?Frequency?(stride/s)? NP? 1.09?(0.04)? 0.53?(0.03)? 0.57?(0.03)? Velocity?(m/s)? NP? 1.10?(0.09)? 0.67?(0.01)? 0.87?(0.01)? Hind?Stance?(s)? 0.65?(0.50)? 0.56?(0.04)? 1.16?(0.12)? 1.02?(0.07)? Fore?Stance?(s)? 0.69?(1.75)? 0.62?(0.04)? 1.30?(0.20)? 1.13?(1.11)? Diagonal?Advanced?Placement?(s)? 0.33?(0.02)? 0.07?(0.04)? 0.13?(0.05)? 0.06?(0.03)? Diagonal?Advanced?Lift?off?(s)? NP? 0.04?(0.03)? 0.09?(0.05)? 0.07?(0.05)? Limb?Support?Phases?(%)? ?????Diagonal?Bipedal? 43.00?(0.00)? 60.00?(8.00)? 57.78?(10.48)? 70.20?(7.37)? ?????Quadrupedal? 9.00?(0.00)? 17.00?(8.00)? 19.26?(4.35)? 14.07?(5.47)? ?????Tripedal?with?two?Forelimbs? 19.00?(8.00)? 16.72?(12.71)? 13.31?(12.68)? ?????Tripedal?with?two?Hindlimbs? 48.00?(0.00)? 4.00??(8.00)? 6.24?(7.28)? 2.41?(4.80)? Vertical?Excursions?(m)? ?????Head?? NP? 0.13?(0.03)? 0.12?(0.05)? 0.12?(0.05)? ?????Croup? NP? 0.09?(0.03)? 0.08?(0.01)? 0.10?(0.01)? ?????Fore?Coffin? NP? 0.23?0.05)? 0.09?(0.02)? 0.10?(0.02)? ?????Hind?Coffin? NP? 0.22?(0.06)? 0.11?(0.01)? 0.11?(0.01)? The?differences?seen?in?the?limb?support?percentages?from?the?previously? studied?jog?to?those?of?the?collected?jog?of?the?current?study?may?be?evidence?of? the? effort? of? the? western? pleasure? industry? to? more? closely? follow? the? gait? definition? set? forth? by? breed? associations.??When? considering? limb? support,? it? may?be?concluded?that?the?industry?has?failed?to?improve?gait?quality?of?the?jog? due?to?the?continued?inclusion?of?tripedal?and?quadrupedal?support?as?well?as? diagonal?couplets?instead?of?diagonal?pairs?during?the?collected?and?extended? 162 jog;? however,? when? taking? into? account? the? changes? seen? in? stride? length,? duration,?frequency,?and?velocity,?it?appears?that?gait?improvements?indeed?have? been?made.??The?increase?in?stride?length?from?the?collected?to?the?extended?jog? found?in?the?current?study?is?in?line?with?breed?association?rules?that?define?the? extended?jog?as?a?lengthening?of?stride?that?covers?more?ground?than?that?of?the? collected?jog?(APHA?2009;?ApHC?2009b;?AQHA?2009;?PHBA?2008).?Further,?the? changes?in?temporal?and?linear?variables?have?resulted?in?forward?moving?yet? slow?legged?horses?that?are?most?desirable?as?show?horses?in?the?current?stock? breed?western?pleasure?industry.??Even?considering?the?positive?changes?in?gait? performance?previously?mentioned,?the?collected?and?extended?jog?still?do?not? completely? meet? the? gait? definitions? set? forth? by? breed? associations.??Breed? association?guidelines?dictate?that?the?jog?(i.e.?collected?jog)?should?be?a?two?beat? diagonal?gait?that?exhibits?diagonal?pairs.??As?determined?by?the?current?study,? stock? breed? western? pleasure? horses? exhibit? diagonal? couplets,? not? diagonal? pairs,?and?do?not?maintain?a?two?beat?rhythm?for?either?the?collected?or?extended? jog.??Additionally,? the? collected? and? extended? jogs? were? determined? to? be? stepping?gaits?(without?suspension)?rather?than?leaping?gaits?(with?suspension).?? Suspension?is?implied?in?current?breed?association?definitions?of?the?gaits?based? on? the? two?beat? requirement? (APHA? 2009;? ApHC? 2009b;? AQHA? 2009;? PHBA? 163 2008).??Thus,?performance?of?the?collected?and?extended?jog?does?not?conform?to? current?breed?association?guidelines.??? Angular kinematics. ? Similarities?can?be?noted?between?the?joint?motion?patterns?of?the?fore?and? hindlimbs?of?stock?breed?western?pleasure?horses?performing?the?jog,?collected? jog,? and? extended? jog.??During?swing?phase,?the?shoulder?gradually?extended? and?the?elbow,?carpus,?and?forelimb?fetlock?gradually?flexed?(Figure?4.3?&?5.3).?? Peak?flexion?of?the?carpus?preceded?the?elbow?during?swing?phase?while?peak? flexion?of?the?forelimb?fetlock?was?not?as?obvious?at?the?jog?as?at?the?collected? and?extended?jog.??Gradual?extension?of?the?elbow?and?carpus?and?flexion?of?the? shoulder? continued? throughout? stance;? peak? extension? of? the? forelimb? fetlock? occurred?at?mid?stance.??The?hip?gradually?extended?throughout?stance?to?reach? peak?extension?at?late?stance;?the?hock?reached?peak?extension?during?stance?and? peak?flexion?at?mid?swing?phase?(Figure?4.4?&?5.4).??During?swing?phase,?the?hip,? stifle,? and? hock? gradually? flexed.??Peak? extension? of? the? hindlimb? fetlock? occurred?during?early?swing?for?all?jogs;?however,?stock?breed?western?pleasure? horses? performing? the? jog? exhibited? another? peak? of? extension? during? swing? phase?that?was?not?present?during?the?collected?or?extended?jog?(Booker?2005;? Nicodemus?and?Booker?2007).??Similarities?in?joint?motion?graphs,?other?than?the? 164 fetlock?joint,?indicate?that?stock?breed?western?pleasure?horses?have?not?adjusted? joint?motions?in?order?to?achieve?the?temporal?or?linear?kinematic?changes?seen? between?the?Nicodemus?and?Booker?(2007)?and?present?study;?the?horses?are?just? moving?slower.??The?secondary?peak?of?fetlock?extension?found?during?swing? phase?in?Nicodemus?and?Booker?(2007)?was?not?found?in?the?current?study?and? indicates?that?horses?are?no?longer??snapping??the?hindlimb?fetlock?to?push?off? the?ground?harder?thereby?eliminating?the?dramatic?fetlock?extension?seen?in?the? previous?study.??? Jog?Forelimb?Joint?Motion? 80 100 120 140 160 180 200 220 240 260 0% 20% 40% 60% 80% 100% Stride?(%) Angle ? (deg) Shoulder Elbow Carpus Fetlock Figure?5.3:??Forelimb?motion?graph?of?the?shoulder,?elbow,?carpus,?and?fetlock? joints?(deg)?as?a?percentage?of?stride?(%)?for?one?stride?of?the?jog?of?the?stock? breed?western?pleasure?horse?(Booker?2005;?Nicodemus?and?Booker?2007).??The? black?vertical?line?indicates?hoof?off.??? 165 Jog?Hindlimb?Joint?Motion 80 100 120 140 160 180 200 220 240 260 0% 20% 40% 60% 80% 100% Stride?(%) Angle ? (deg) Hip Stifle Hock Fetlock Figure?5.4:??Hindlimb?motion?graph?of?the?hip,?stifle,?hock,?and?fetlock?joints? (deg)?as?a?percentage?of?stride?(%)?for?one?stride?of?the?jog?of?the?stock?breed? western?pleasure?horse?(Booker?2005;?Nicodemus?and?Booker?2007).??The?black? vertical?line?indicates?hoof?off.??? ? ? Breed?association?guidelines.? The?AQHA?s?Official?Handbook?of?Rules?and?Regulations?(2009)?indicates? that?the?jog?should?be??a?smooth,?ground?covering?two?beat?diagonal?gait.?The? horse? works? from? one? pair? of? diagonals? to? the? other? pair.??The? jog? should? be? square,?balanced?and?with?straight,?forward?movement?of?the?feet??(p.140?141).?? As?well,??[w]hen?asked?to?extend?the?jog,?it?moves?out?with?the?same?smooth? way?of?going??(p.?140).??AQHA?(2009)?further?indicates?that?western?pleasure? horses???should?carry?his?head?and?neck?in?a?relaxed,?natural?position,?with?his? 166 poll?level?with?or?slightly?above?the?level?of?the?withers??(p.?215).??Other?major? stock? breed? associations? follow? the? guidelines? set? forth? by? AQHA? with? only? minor?changes?in?wording?(APHA?2009;?ApHC?2009b;?AQHA?2009;?PHBA?2008).??? Based?on?the?above?guidelines?for?gait?performance?and?the?scientifically? determined? temporal,? linear,? and? angular? kinematic? variables? presented? in? previous? paragraphs,? the? extended? jog? does? more? closely? follow? some? of? the? guidelines? set? forth? by? major? stock? breed? associations? for? western? pleasure? competition? than? does? the? collected? jog.??The? extended? jog? indicated? greater? synchronization? of? diagonal? pairs? than? the? collected? jog? thereby? more? closely? following?the?two?beat?requirement?of?the?jog?as?set?forth?by?breed?associations.?? Greater?synchronization?of?the?diagonal?pairs?is?most?likely?due?to?the?increased? stride? length? and? velocity? found? in? the? extended? jog? when? compared? to? the? collected?jog.??However,?had?the?extended?jog?completely?conformed?to?the?two? beat?requirement?for?the?jog,?the?smoothness?of?the?gait?would?have?been?lost;?the? lack? of? suspension? and? inclusion? of? diagonal? couplets? means? there? is? no? ?bounce?? in? the? stride? and? allows? for? a? smooth,? comfortable? ride.??Correct? performance?of?a?two?beat?gait?includes?suspension,?which?creates??bounce??and? therefore?roughness?during?the?ride.??Losing?the?smoothness?of?the?stride?would? be? contradictory? to? all? stock? horse? breed? association? guidelines.??Horses? performing? the? collected? and? extended? jog? carried? a? level? topline? that? does? 167 correspond?to?guidelines?for?gait?performance.??Therefore,?it?would?be?prudent?of? major?stock?breed?associations?to?take?into?consideration?the?way?in?which?the? jog?is?currently?being?performed?and?either?adapt?current?western?pleasure?gait? definitions?to?more?closely?match?what?is?being?performed?or?to?fully?enforce?the? gait?definitions?as?written.??The?area?in?which?horses?are?in?direct?violation?of? breed? association? guidelines? is? in? regards? to? a? two?beat? gait? for? the? jog,? so? to? make? educated? decisions? concerning? the? adaptation? of? gait? definitions,? breed? associations?must?choose?between?a?two?beat?gait,?which?will?not?be?smooth,?and? the?current?performance?of?the?jog?as?a?four?beat?jog,?which?is?smooth.??? With?respect?to?horses?moving?from?the?collected?to?extended?jog,?horses? performing?the?extended?jog?had?an?increased?stride?length?and?velocity?when? compared? to? the? collected? jog.??This? increase? in? stride? length? and? velocity? indicates?that?horses?did??move?out??and?follow?recommendations?related?to?gait? performance.??Further,?the?insignificance?seen?for?forelimb?as?well?as?hock?and? hindlimb? fetlock? angular? kinematics? indicate? that? horses? moved? out? from? the? collected?jog??with?the?same?smooth?way?of?going??as?the?extended?jog?due?to?the? fact? that? horses? did? not? adjust? joint? motions? to? achieve? temporal? or? linear? kinematic?changes;?the?horses?just?moved?faster?and?covered?more?ground.??For? these?reasons,?horses?did?more?closely?follow?breed?guidelines?with?regards?to? performance?of?the?extended?jog?when?compared?to?the?collected?jog.? 168 Collected?and?Extended?Lope? ? Temporal?and?linear?kinematics.? ? In?the?current?study,?the?left?lead?collected?lope?as?well?as?the?right?and?left? lead? extended? lope? were? performed? with? a? lateral? footfall? sequence? while? the? right?lead?collected?lope?was?performed?with?a?diagonal?footfall?sequence.??All? four?gaits?were?performed?as?asymmetrical?four?beat?stepping?gaits,?having?no? period?of?suspension,?and?no?periods?of?quadrupedal?support.??Diagonal?limb? pairs?moved?closely?together?in?time,?creating?a?diagonal?couplet,?and?rarely?was? hoof?placement?or?lift?off?made?at?precisely?the?same?moment.??Disuniting?the? diagonal?pair?created?a?gait?with?a?four?beat?rhythm.??Comparisons?between?the? current? study? and? the? Nicodemus? and? Clayton? (2001a)? and? Nicodemus? and? Booker? (2007)? indicate? changes? in? performance? over? time? (Table? 5.2).??Stride? length? and? duration? have? increased? while? stride? frequency? and? velocity? have? decreased;?even?the?right?and?left?lead?extended?lope?was?not?performed?at?a? velocity? found? in? Nicodemus? and? Booker? (2007)? (Table? 5.2).??These? findings? indicate?that?current?stock?breed?western?pleasure?horses?are?exhibiting?longer? stride?lengths?and?durations?but?slower?stride?frequencies?and?velocities?than?did? previous? research? on? stock? breed? western? pleasure? horses.??The? relationship? between?stride?length,?stride?duration,?stride?frequency,?and?velocity?indicates? that? the? horse?s? legs? are? covering? more? distance? yet? moving? slower.??The? 169 differences? seen? in? the? above? mentioned? temporal? and? linear? variables? have? resulted?in?a?slower?moving?stock?breed?western?pleasure?horse?most?likely?due? to?a?combination?of?breeding?and?training?associated?with?breed?association?rule? changes?implemented?since?the?previous?research?was?conducted.??Horses?that? cover?more?ground?per?step?yet?move?the?legs?more?slowly?are?more?desirable?in? the? current? stock? breed? western? pleasure? horse? industry? because? the? horse? is? more?closely?following?breed?association?guidelines?with?regards?to?the?collected? and? extended? lope? being? ground?covering? gaits? (APHA? 2009;? ApHC? 2009b;? AQHA?2009;?PHBA?2008)? In?accordance?with?Nicodemus?and?Booker?(2007),?horses?in?the?present? study? performed? the? right? and? left? lead? collected? and? extended? lope? without? periods? of? quadrupedal? support? unlike? those? horses? in? the? Nicodemus? and? Clayton?(2001a)?(Table?5.2).??The?percentage?of?tripedal?limb?support?found?for? horses?in?the?present?study?was?between?that?of?the?horses?in?the?Nicodemus?and? Booker?(2007)?and?Nicodemus?and?Clayton?(2001a).??The?current?horses?spent?a? lesser? percentage? of? stride? in? diagonal? bipedal? limb? support? and? a? greater? percentage?of?stride?in?unipedal?forelimb?support?than?did?previously?studied? stock? breed? western? pleasure? horses.??Differences? seen? in? limb? support? percentages?between?the?present,?Nicodemus?and?Booker?(2007),?and?Nicodemus? 170 and?Clayton?(2001a)?are?most?likely?due?to?the?speed?at?which?the?gaits?were? performed.??? Comparisons? concerning? vertical? excursions? of? the? head? indicate? only? slight?differences?between?the?lope,?collected,?and?extended?lope?while?the?croup? of?horses?in?the?present?study?appear?to?have?much?greater?vertical?excursions? than?did?the?horses?in?previous?work?(Table?5.2).??Vertical?excursions?of?the?coffin? suggest?that?current?stock?breed?western?pleasure?horses?do?not?pick?their?hooves? up?as?high?as?past?stock?breed?western?pleasure?horses?(Table?5.2)?(Nicodemus? and?Booker?2007).? 171 Table?5.2:??Means?(??s.d.)?for?temporal?and?linear?variables?of?the?collected?and?extended?lope?for?the?present?study?and? the?lope?from?the?Nicodemus?and?Clayton?(2001a)?as?well?as?the?Nicodemus?and?Booker?study?(2007).??NP?indicates? temporal?or?linear?variables?that?were?not?present?in?the?Nicodemus?and?Clayton?(2001a)?study.??Collected?and?extended? lope?variables?linear?variables?are?as?calculated?from?right?hind?down?placements.??Tripedal?with?two?forelimbs?and? tripedal?with?two?hindlimbs?support?phases?as?well?as?diagonal?bipedal?limb?support?phases?have?been?combined?for?the? sake?of?comparison.? Collected?Lope? Extended?Lope? ? Lope?? (2001a)? Left?Lead?Lope? (2007)? Right? Left? Right? Left? Stride?Length?(m)? NP? 1.24?(0.09)? 1.57?(0.18)? 1.50?(0.17)? 1.68?(0.15)? 1.70?(0.21)? Stride?Duration?(s)? 0.72?(0.03)? 0.72?(0.04)? 1.35?(0.07)? 1.39?(0.08)? 1.32?(0.08)? 1.33?(0.08)? Stride?Frequency?(stride/s) NP? 1.40?(0.08)? 0.74?(0.04)? 0.72?(0.04)? 0.76?(0.05)? 0.76?(0.05)? Velocity?(m/s)? NP? 1.74?(0.13)? 1.16?(0.15)? 1.09?(0.13)? 1.28?(0.12)? 1.28?(0.19)? Limb?Support?Phases?(%)? ?????Tripedal? 49.00?(0.00) 36.00?(7.00)? 44.68?(5.30)? 41.55?(7.54) 40.11?(6.43) 43.02?(6.58) ?????Diagonal?Bipedal? 39.00?(0.00) 44.00?(6.00)? 34.09?(8.28)? 36.41?(9.38) 33.56?(8.73) 32.00?(9.71) ?????Unipedal?Fore? 4.00?(0.00)? 7.00?(2.00)? 9.20?(2.16)? 10.00?(3.78) 14.37?(2.45) 13.80?(4.56) ?????Quadrupedal? 2.00?(0.00)? 0.00?(0.00)? 0.00?(0.00)? 0.00?(0.00)? 0.00?(0.00)? 0.00?(0.00)? Vertical?Excursions?(m)? ?????Head?? NP? 0.44?(0.14)? 0.41?(0.09)? 0.42?(0.11)? 0.40?(0.05)? 0.38?(0.09)? ?????Croup? NP? 0.18?(0.04)? 0.40?(0.08)? 0.51?(0.13)? 0.32?(0.20)? 0.45?(0.06)? ?????Leading?Fore?Coffin? NP? 0.25?(0.06)? 0.15?(0.02)? 0.12?(0.02)? 0.15?(0.03)? 0.13?(0.02)? ?????Trailing?Fore?Coffin? NP? 0.30?(0.08)? 0.15?(0.03)? 0.17?(0.02)? 0.15?(0.02)? 0.18?(0.03)? ?????Leading?Hind?Coffin? NP? 0.25?(0.08)? 0.13?(0.02)? 0.16?(0.04)? 0.13?(0.03)? 0.18?(0.04)? ?????Trailing?Hind?Coffin? NP? 0.30?(0.06)? 0.15?(0.05)? 0.14?(0.02)? 0.15?(0.04)? 0.13?(0.02)? 172 Diagonal?advanced?placements?and?lift?offs?indicate?that?the?collected?and? extended?lopes?were?performed?with?diagonal?couplets?instead?of?diagonal?pairs? indicating?that?while?the?diagonal?limbs?moved?in?concert,?they?did?not?move? synchronously?(Table?5.3).??When?evaluating?the?trailing?fore?to?leading?hindlimb? advanced?placements,?the?greatest?time?between?placement?of?the?diagonal?pairs? was?seen?at?the?right?lead?extended?lope?and?indicates??poorer??gait?performance? when? compared? to? the? right? and? left? lead? collected? lope? or?left?lead?extended? lope;?however,?the?left?lead?extended?lope?indicated?the?greatest?synchronization? of?diagonal?pair?placement?when?compared?to?other?lopes.??These?differences?in? diagonal? pair? synchronization? are? most? likely? due? to? the? ?handedness?? or? preference?of?the?horses?to?perform?one?lead?better?than?another?(Deuel?and?Park? 1990).??In?order?to?control?for?the??handedness??of?the?rider,?the?same?rider?rode? all?horses.??Advanced?placement?in?the?stock?breed?western?pleasure?horse?was? longest?between?the?leading?fore?and?trailing?hind?which?is?in?line?with?previous? Nicodemus?and?Clayton?(2001a)?work?but?contrary?to?Nicodemus?and?Booker? (2007).??This? time? period? between? placement? of? the? leading? fore? and? trailing? hindlimb?is?usually?reserved?for?suspension?in?other?breeds?of?horses,?but?the? stock?breed?western?pleasure?horse?has?adapted?the?lope?as?a?stepping?gait?rather? than?a?leaping?gait?(Clayton?1994a).??? 173 Table? 5.3:??Means? (?? s.d.)? for? diagonal? advanced? placement? and? diagonal? advanced? lift?off? (s)? of? the? collected? and? extended?lope?for?the?present?study?and?the?lope?from?the?Nicodemus?and?Clayton?(2001a)?as?well?as?the?Nicodemus?and? Booker?study?(2007).??NP?indicates?temporal?or?linear?variables?that?were?not?present.??? Collected?Lope? Extended?Lope? ? Lope? (2001a)? Left?Lead? Lope? (2007)? Right? Left? Right? Left? Advanced?Placement?(s)? ?????Leading?Fore?to?Leading?Hind? 0.21?(0.02)? 0.27?(0.06)? 0.49?(0.04)? 0.58?(0.17)? 0.48?(0.05)? 0.47?(0.05)? ?????Leading?Fore?to?Trailing?Hind? 0.02?(0.00)? 0.21?(0.04)? 0.82?(0.15)? 0.80?(0.14)? 0.71?(0.19)? 0.85?(0.12)? ?????Trailing?Fore?to?Leading?Hind? 0.22?(0.03)? 0.04?(0.03)? 0.19?(0.39)? 0.16?(0.19)? 0.38?(0.51)? 0.12?(0.20)? ?????Trailing?Fore?to?Trailing?Hind?? 0.42?(0.03)? 0.22?(0.06)? 0.40?(0.05)? 0.47?(0.14)? 0.35?(0.07)? 0.43?(0.26)? Advanced?Lift?off?(s)? ?????Leading?Fore?to?Leading?Hind? NP? 0.23?(0.04)? 0.49?(0.06)? 0.47?(0.03)? 0.46?(0.05)? 0.48?(0.08)? ?????Leading?Fore?to?Trailing?Hind? NP? 0.17?(0.04)? 0.85?(0.18)? 0.76?(0.23)? 0.58?(0.15)? 0.87?(0.10)? ?????Trailing?Fore?to?Leading?Hind? NP? 0.04?(0.02)? 0.09?(0.12)? 0.17?(0.21)? 0.04?(0.03)? 0.03?(0.01)? ?????Trailing?Fore?to??Trailing?Hind?? NP? 0.29?(0.05)? 0.85?(0.18)? 0.76?(0.23)? 0.58?(0.15)? 0.45?(0.06)? 174 Angular?kinematics.? ? Similarities?can?be?noted?between?the?joint?motion?patterns?of?the?leading? fore?and?hindlimbs?of?stock?breed?western?pleasure?horses?performing?the?lope,? collected?lope,?and?extended?lope.??During?stance?phase,?the?elbow?and?carpus? gradually?extended?and?the?fetlock?reached?peak?extension?(Figure?4.15,?5.5,?&? 5.6).??The?shoulder?gradually?flexed?throughout?stance?(Figure?5.5).??The?elbow,? carpus,?and?fetlock?gradually?flexed?throughout?swing?phase?(Figure?5.5?&?5.6).?? Peak?flexion?of?the?carpus?occurred?prior?to?peak?flexion?of?the?elbow?and?peak? extension?of?the?shoulder?occurred?in?early?swing;?peak?flexion?of?the?forelimb? fetlock?was?not?as?obvious?at?the?lope?as?at?the?collected?and?extended?lope.?? ? ? Figure?5.5:??Mean?(solid?lines)???SD?(dashed?lines)?joint?motion?for?the?shoulder? and?elbow?joints?of?the?leading?forelimb?during?the?lope?of?the?stock?breed? western?pleasure?horse?(Nicodemus?and?Booker?2007).??The?black?vertical?line? indicates?hoof?off.??? Elbow Shoulder Leading?Forelimb?Shoulder?and?Elbow?Joint?Motion?During?the?Lope 175 Figure?5.6:??Mean?(solid?lines)???SD?(dashed?lines)?joint?motion?for?the?carpus? and?forelimb?fetlock?joints?of?the?leading?forelimb?during?the?lope?of?the?stock? breed? western? pleasure? horse? (Nicodemus? and? Booker? 2007).??The? black? vertical?line?indicates?hoof?off.??? ? ? The?hip,?stifle,?and?hock?gradually?flexed?and?then?extended?throughout? stance?(Figure?4.17,?5.7,?&?5.8).??During?swing?phase,?the?hip,?stifle,?and?hock? gradually?flexed?(Figure?5.7).??Peak?flexion?of?the?hindlimb?fetlock?was?not?as? obvious?at?the?lope?as?at?the?collected?and?extended?lope?(Figure?5.8)?(Booker? 2005;?Nicodemus?and?Booker?2007).??Similarities?in?joint?motion?graphs?indicate? that? stock? breed? western? pleasure? horses? have? not? adjusted? joint? motions? to? achieve?the?temporal?or?linear?kinematic?changes?seen?between?the?Nicodemus? and?Booker?(2007)?and?the?present?study;?the?horses?are?just?moving?slower.??It? should? be? noted? that? trailing? fore? and? hindlimbs? of? the? loping? stock? breed? Forelimb?Fetlock Carpus Leading?Forelimb?Carpus?and?Fetlock?Joint?Motion?During?the?Lope 176 western? pleasure? horse? have? not? been? previously? examined,? so? further? comparisons?of?angular?kinematics?cannot?be?made. Figure?5.7:??Mean?(solid?lines)???SD?(dashed?lines)?joint?motion?for?the?hip?and? stifle?joints?of?the?leading?hindlimb?during?the?lope?of?the?stock?breed?western? pleasure?horse?(Nicodemus?and?Booker?2007).??The?black?vertical?line?indicates? hoof?off.??? Hip Stifle? Leading?Hindlimb?Hip?and?Stifle?Joint?Motion?During?the?Lope? 177 Figure?5.8:??Mean?(solid?lines)???SD?(dashed?lines)?joint?motion?for?the?hock?and? hindlimb?fetlock?joints?of?the?leading?hindlimb?during?the?lope?of?the?stock? breed? western? pleasure? horse? (Nicodemus? and? Booker? 2007).??The? black? vertical?line?indicates?hoof?off.??? ? ? Breed?association?guidelines.? ? The?AQHA?s?Official?Handbook?of?Rules?and?Regulations?(2009)?indicates? that?the?lope?should?be?? ?an? easy,? rhythmical? three?beat? gait.? Horses? moving?to?the?left?should? lope?on?the?left?lead.?Horses?moving?to?the?right?should?lope?on?the?right? lead.? Horses? traveling? at? a? four?beat? gait? are? not? considered? to? be? performing?at?a?proper?lope.?The?horse?should?lope?with?a?natural?stride? and?appear?relaxed?and?smooth.?It?should?be?ridden?at?a?speed?that?is?a? natural?way?of?going.?(141)? Hock Hindlimb?Fetlock? Leading?Hindlimb?Hock?and?Fetlock?Joint?Motion?During?the?Lope 178 As?well,??[e]xcessive?slowness?in?any?gait,?loss?of?forward?momentum?(resulting? in?an?animated?and/or?artificial?gait?at?the?lope)??is?considered?a?fault?that?should? be?penalized?according?to?severity??(p.?216).??Other?major?stock?breed?associations? follow?the?guidelines?set?forth?by?AQHA?with?only?minor?changes?in?wording? (APHA?2009;?ApHC?2009b;?AQHA?2009;?PHBA?2008).??? ? Based?on?the?above?guidelines?for?gait?performance?and?the?scientifically? determined? temporal,? linear,? and? angular? kinematic? variables? presented? in? previous? paragraphs,? it? is? still? unclear? as? to? whether? the? extended? lope? more? closely? follows? the? guidelines? set? forth? by? major? stock? breed? associations? for? western?pleasure?competition?than?does?the?collected?lope.??Only?the?left?lead? extended?lope?indicated?greater?synchronization?of?the?diagonal?pair?and?more? closely? followed? the? three?beat? requirement? of? the? lope? as? set? forth? by? breed? associations.??While?greater?synchronization?of?the?diagonal?pair?during?the?left? lead?extended?lope?is?most?likely?due?to?the?increased?stride?length?and?velocity? found?in?the?extended?lope?when?compared?to?the?left?lead?collected?lope,?the? same? was? not? true? for? the? right? lead? extended? lope? when? compared? to? the? collected?lope.??However,?had?the?extended?lopes?completely?conformed?to?the? three?beat?requirement?for?the?lope,?the?smoothness?of?the?gait?would?have?been? lost;?the?lack?of?suspension?and?inclusion?of?diagonal?couplets?means?there?is?no? ?bounce?? in? the? stride? and? allows? for? a? smooth,? comfortable? ride.??Correct? 179 performance? of? a? three?beat? gait? includes? suspension,? which? creates? ?bounce?? and?therefore?roughness?during?the?ride.??Losing?the?smoothness?of?the?stride? would? be? contradictory? to? stock? horse? breed? association? guidelines.??Horses? performing? the? collected? and? extended? lopes? did? not? indicate? proper? head? carriage? or? a? level? topline? and? did? not? conform? to? guidelines? for? gait? performance.??Therefore,?it?would?be?prudent?of?major?stock?breed?association?s? to?take?into?consideration?the?way?in?which?the?lope?is?currently?being?performed? and?either?adapt?current?western?pleasure?gait?definitions?to?more?closely?match? what?is?being?performed?or?to?fully?enforce?the?gait?definitions?as?written.??The? two?areas?in?which?horses?are?in?direct?violation?of?breed?association?guidelines? are?in?regards?to?a?three?beat?gait?and?level?topline?during?the?lope,?so?to?make? educated? decisions? concerning? the? adaptation? of? gait? definitions,? breed? associations?must?choose?between?a?three?beat?gait,?which?will?not?be?smooth,? and? the? current? performance? of? the? four?beat? lope,? which? is? smoother.??In? addition,? breed? association? guidelines? should? attempt? to? address? the? topline? variability.??? Although?dropped?by?the?AQHA?(2009),?the?forward?motion?clause?which? states?that??[l]ope?with?forward?motion?will?become?the?only?gait?recognized?as?a? lope?? is? still? present? in? the? APHA? (2009),? PHBA? (2008),? and? ApHC? (2009b)? rulebooks.??With?respect?to?horses?moving?from?the?collected?to?extended?lope,? 180 horses?performing?the?extended?lope?had?an?increased?stride?length?and?velocity? when?compared?to?the?collected?lope.??This?increase?in?stride?length?and?velocity? indicates?that?horses?did??move?out??when?asked?to?extend?the?lope;?however,? based?on?the?increase?in?stride?length?from?the?earlier?lope?studies?to?the?current? study,?it?is?fair?to?suggest?that?horses?were?already?moving?with?forward?motion? at?the?collected?lope?and?did?not?need?to?further?extend?the?stride?to?comply?with? breed?association?guidelines?(Nicodemus?and?Booker?2007).??While?horses?may? have? already? been? moving? with? ?forward? motion?? the? slight? adjustments? in? vertical?excursions?of?the?head?and?croup?indicate?that?the?extended?lope?was? ?easier??and?less?balance?compromising?to?perform?because?horses?were?able?to? maintain? a? more? level? topline.??It? is? interesting? to? note,? however,? that? the? insignificance?seen?for?angular?kinematics?for?the?right?lead?collected?to?extended? lope?and?the?forelimb?as?well?as?hindlimb?fetlock?angular?kinematics?for?the?left? lead? collected? to? extended? lope? indicates? that? horses? ?moved? out?? from? the? collected?lope?to?the?extended?lope?due?to?the?fact?that?horses?did?not?adjust?joint? motions?in?order?to?achieve?temporal?or?linear?kinematic?changes;?the?horses?just? moved?faster?and?covered?more?ground. ? ? ? ? 181 Injuries? Following? current? breeding? trends? for? stock? breed? western? pleasure? horses,?horses?in?the?current?study?were?taller?and?had?less?muscle?mass?over?the? shoulders? and? hindquarters? with? steeper? shoulder? and? pastern? angles? than? typical?stock?horses?(Black?1999).??All?horses?were?shod?at?steep?hoof?angles?with? aluminum?shoes,?which?increased?hoof?angle?and?decreased?breakover?time?for? carpus? flexion? to? allow? for? the? ?flat? kneed?? appearance? of? the? stock? breed? western?pleasure?horse.??It?should?also?be?noted?that?none?of?the?horses?used?in? the?current?study?had?been?subjected?to?intra?articular?joint?injections?of?the?stifle,? hock,?fetlock,?or?coffin?for?osteoarthritis?within?the?last?year,?which?eliminates? joint? injections? with? any? substance? as? a? variable? in? the? current? study.??No? scientific?literature?exists?directly?linking?western?pleasure?to?osteoarthritis,?but?it? is?accepted?in?the?equine?industry?that?elite?performance?horses?that?have?been? showing?at?the?national?level?since?the?age?of?two?do?not?often?maintain?a?show? career?after?the?age?of?five.??This?lack?of?senior?aged?performance?horses?has?been? anecdotally?linked?to?osteoarthritis?induced?by?the?intense?training?these?horses? receive?early?in?their?show?career?and?the?ultra?slow?gait?they?are?expected?to? achieve.??For?the?current?study,?the?oldest?horse?was?8?years?while?the?youngest? horse?was?3?years,?and?one?reason?these?horses?had?not?been?subjected?to?joint? injections?may?be?due?to?a?late?start,?for?whatever?reason,?in?western?pleasure? 182 training? thereby? potentially? reducing? the? injury? to? the? joint? and? the? need? for? injection?of?anti?inflammatory?agents.??Another?contributing?factor?that?lessened? the?need?for?joint?injections?in?these?relatively?young?horses?might?be?the?changes? in? breed? association? guidelines? for? gait? performance? of? stock? breed? western? pleasure?horses.??By?encouraging?horses?to?have?a?natural?stride?of?reasonable? length? and? rewarding? those? horses? with? forward? motion,? stock? breed? associations? might? anecdotally? be? reducing? injury? to? stock? breed? western? pleasure? horses? (APHA? 2009;? ApHC? 2009b;? AQHA? 2009;? PHBA? 2008).??Rule? changes?inducted?in?2005?may?be?showing?effectiveness?in?the?current?horses?? collected?jog?and?lope?based?on?the?current?study?s?subjects,?so?it?is?reasonable?to? assume?that?the?extended?jog?and?lope?would?continue?this?trend?and?conform?to? a? more? natural? way? of? going? for? stock? breed? western? pleasure? horses? thereby? reducing?risk?of?joint?injury?and?trauma?than?does?the?collected?jog?and?lope.??? Furthering?this?argument?that?the?extended?jog?and?lope?are?more?natural? to?the?horse?s?way?of?going?are?the?shifts?in?limb?support?percentages?seen?when? moving?from?the?collected?jog?and?lope?to?the?extended?jog?and?lope.??Previous? research?has?indicated?that?having?more?limbs?on?the?ground?increases?stability? because? limb? support? is? related? to? speed? (Clayton? 1989;? Hodson? et? al.? 1999;? Nicodemus?and?Clayton?2001a).??In?effect,?the?slower?the?horse?is?moving?the? more?limbs?are?on?the?ground?at?one?time?as?the?horse?must?compensate?for?the? 183 lack?of?dynamic?stability?(Hodson?et?al.?1999).??Other?equine?gaits?that?have?been? found? to? lack? forward? motion? include? longer? periods? of? tripedal? and? quadrupedal?limb?support?that?are?not?found?at?faster?versions?of?the?same?gait? (Burns? and? Clayton? 1997;? Clayton? 1997;? Hodson? et? al.? 1999;? Leach? 1986).???In? parallel,? the? current? stock? breed? western? pleasure? study? indicated? a? greater? percentage? of? stride? spent? in? diagonal? bipedal? limb? support? and? a? lesser? percentage? of? stride? spent? in? quadrupedal? and? tripedal? limb? supports? when? horses?moved?from?the?collected?to?the?extended?jog?(Table?5.1).??While?opposite? effects? were? found? in? the? percentage? of? stride? horses? spent? in? tripedal? limb? support?when?moving?from?the?right?collected?to?extended?lope?than?from?the? left? collected? to? extended? lope,? both? leads? indicated? a? decrease? in? diagonal? bipedal?and?in?increase?in?unipedal?forelimb?support?(Table?5.2).???As?well,?the? increase? in? stride? length? found? in? horses? moving? to? the? extended? from? the? collected?versions?of?the?jog?and?lope?allows?the?horse?to?have?a?greater?base?of? support?and?greater?forward?motion.??Thus,?it?can?be?suggested?that?both?the? collected? jog? and? lope? lack? forward? motion? thereby? challenging? the? horse?s? balance?to?a?higher?degree?than?does?the?extended?jog?and?lope.??? Another? indication? that? the? collected? jog? and? lope? do? increase? the? challenge? to? a? horse?s? balance? is? vertical? excursion? of? the? head? and? croup.?? Vertical? excursion? of?the?head?and?croup?did?not?change?when?horses?moved? 184 from?the?collected?to?extended?jog,?but?this?finding?is?not?surprising?due?to?the? symmetry?and?balanced?nature?of?the?jog?(Table?5.1).??However,?an?asymmetrical? gait?such?as?the?lope?that?is?performed?at?such?slow?velocities?is?an?ideal?gait?in? which?to?visually?and?quantitatively?assess?balance?based?on?topline?excursion.? Vertical?excursions?of?both?the?head?and?croup?decreased?when?horses?moved? from?the?right?and?left?lead?collected?to?extended?lope?(Table?5.2).??The?ability?of? horses? to? hold? a? steadier? topline? during? the? extended? lope? indicates? that? the? increased?forward?motion,?based?on?an?increase?in?stride?length,?combined?with? the?shift?in?limb?support?phases?decreases?the?balance?challenge?and?increases? dynamic?stability?when?compared?to?the?collected?lope.??? For? example,? consider? a? person? hopping? forward? on? one? foot? while? moving?in?slow?motion.??Not?only?is?there?an?obvious?challenge?to?balance?that? has?been?intensified?by?decreasing?forward?motion,?the?risk?for?injury?is?easy?to? visualize?as?the?human?wobbles?to?maintain?balance.???In?effect,?this?very?same? scenario?is?occurring?when?horses?are?asked?to?move?forward?at?slow?velocities,? so?as?does?the?human?when?the?compromise?in?balance?is?too?great,?the?horse? puts? additional? limbs? on? the? ground? to? increase? balance? and? shows? greater? vertical?excursions?over?the?topline.???The?additional?limb?support?phases?and? ?wobbling?? of? the? topline? indicate? a? loss? in? dynamic? stability? and? may? be? translated?to?the?risk?of?injury?to?the?horse.??While?no?scientific?research?exists?to? 185 directly?link?lack?of?balance?to?injury?in?stock?breed?western?pleasure?horses,?it?is? reasonable?to?conclude?that?the?increased?demands?associated?with?threatened? balance?could?lead?to?injuries.? ? Summary? ? In? summary,? results? indicate? that? horses? exhibited? more? desirable? head? carriage?and?a?level?topline?during?the?collected?and?extended?jog?that?was?not? found?during?the?collected?and?extended?lope.??As?well,?stride?length?was?not? altered?independently?of?stride?duration?due?to?the?changes?seen?in?stride?length,? stride?duration,?stride?frequency,?and?velocity?when?the?collected?jog?and?lope? are?compared?to?the?extended?jog?and?lope.?Stock?breed?western?pleasure?horses? perform?the?collected?and?extended?jog?as?symmetrical?four?beat?stepping?gaits? with?no?period?of?suspension?and?diagonal?couplets?instead?of?diagonal?pairs.?? The?extended?jog?was?performed?with?a?greater?stride?length,?stride?frequency,? and? velocity? than? the? collected? jog? but? shorter? stride? duration.??Lack? of? suspension?as?well?as?periods?of?quadrupedal?and?tripedal?limb?support?during? the?jog?indicated?that?stock?breed?western?pleasure?horses?had?limited?forward? motion?that?leads?to?a?loss?of?dynamic?stability.??Ultimately,?the?extended?jog? indicated?greater?synchronization?of?diagonal?pairs?than?the?collected?jog?thereby? 186 more?closely?following?the?two?beat?requirement?of?the?jog?as?set?forth?by?breed? associations.??? The?left?lead?collected?lope?as?well?as?the?right?and?left?lead?extended?lope? were? performed? with? a? lateral? footfall? sequence? while? the? right? lead? collected? lope?was?performed?with?a?diagonal?footfall?sequence.??All?four?loping?gaits?were? performed? as? asymmetrical? four?beat? stepping? gaits? with? leads? that? had? no? period?of?suspension?and?no?periods?of?quadrupedal?support.??However,?based? on? the? inconsistencies? in? diagonal? synchronization? at? the? extended? lope? it? is? unclear?as?to?whether?the?extended?lope?more?closely?follows?the?guidelines?set? forth?by?major?stock?breed?associations?for?western?pleasure?competition?than? does?the?collected?lope?with?regards?to?the?three?beat?requirement?of?the?lope.?? An? increase? in? stride? length? and? velocity? when? moving? from? the? collected? to? extended?lope?indicates?that?horses?did??move?out??when?asked?to?extend?the? lope,?but?based?on?the?increase?in?stride?length?from?the?earlier?lope?studies?to?the? current?study,?it?is?fair?to?suggest?that?horses?were?already?moving?with?forward? motion?at?the?collected?lope?and?did?not?need?to?further?extend?the?stride?in?order? to? comply? with? breed? association? guidelines? with? regards? to? forward? motion.?? However,? the? changes? seen? in? vertical? excursions? of? the? lope? when? horses? performed?the?extended?lope?when?compared?to?the?collected?lope?indicate?that,? theoretically,?more?forward?motion?may?be?the?answer?when?considering?topline? 187 stability.??The?combination?of?diagonal?synchronization?inconsistencies,?forward? motion,?and?topline?variability?leaves?the?question?as?to?whether?the?extended? lope?more?closely?follows?guidelines?set?forth?by?major?stock?breed?registries?for? western?pleasure?competition?than?does?the?collected?lope?mostly?unanswered? and?provides?the?foundation?for?additional?research?associated?with?stock?breed? western?pleasure?horses.??? Therefore,?it?would?be?prudent?of?major?stock?breed?association?s?to?take? into? consideration? the? way? in? which? the? jog? and? lope? are? currently? being? performed? and? either? adapt? current? western? pleasure? gait? definitions? to? more? closely?match?what?is?being?performed?or?to?fully?enforce?the?gait?definitions?as? written.??Stock? breed? western? pleasure? horses? are? in? direct? violation? of? breed? association?guidelines?in?regards?to?the?two?beat?nature?of?the?jog?and?three?beat? nature? of? the? lope,? so? in? order? to? make? educated? decisions? concerning? the? adaptation? of? gait? definitions? breed? associations? should? choose? between? the? smoothness?of?the?gait?and?the?correctness?of?beats?as?well?as?address?topline? carriage? during? the? lope.??Recommendations? concerning? changes? to? lope? guidelines? are? made? cautiously? as? data? showed? inconsistencies? between? the? collected? and? extended? lope? that? resulted? in? the? inability? to? draw? complete? conclusions?regarding?performance.? 188 It?can?be?suggested?that?the?rule?changes?of?2005?have?made?an?impact?on? the? injury? rate? of? stock? breed? western? pleasure? horses? when? examining? the? current? pool? of? subjects.??By? encouraging? horses? to? have? natural? stride? of? reasonable?length?and?rewarding?those?horses?with?forward?motion,?stock?breed? associations? might? anecdotally? be? reducing? injury? to? stock? breed? western? pleasure? horses? (APHA? 2009;? ApHC? 2009b;? AQHA? 2009;? PHBA? 2008).??So,? continued? gait? definition? transformations? should? theoretically? improve? gait? quality?and?continue?to?reduce?injury?rates?resulting?in?healthier,?happier?stock? breed?western?pleasure?horses?and?owners.??Based?on?the?previous?statement,?I? propose?that?stock?breed?association?change?gait?definitions?to?more?fully?and? completely? identify? the? jog? and? lope? of? western? pleasure? horses? as? four?beat? stepping?gaits?without?visible?separation?of?the?diagonal?pairs.??This?definition? change? would? 1)? keep? the? smoothness? of? the? gaits,? 2)? disregard? the? implied? suggestion?of?suspension?required?during?the?jog?and?lope,?3)?continue?with?the? gait?quality?improvements?already?in?place?thereby?reducing?injury,?and?4)?more? appropriately?categorize?the?jog?and?lope?of?stock?breed?western?pleasure?horses.??? 189 Chapter?VI? ? Conclusion? The? purpose? of? this? study? was? to? collect? temporal,? linear,? and? angular? kinematics?of?the?stock?breed?western?pleasure?horse?in?order?to?compare?the? variables?of?the?collected?and?extended?jog?and?the?collected?and?extended?lope? to? determine? consistency? with? current? rulebooks? of? major? stock? breed? associations.??Additionally,?this?study?sought?to?determine?if?the?extended?jog? and? lope? conform? to? a? more? natural? way? of? going? for? stock? breed? western? pleasure?horses,?which?may?reduce?the?risk?of?joint?injury?and?trauma?than?does? the?collected?jog?and?lope.??The?current?chapter?presents?the?conclusion?on?the? topics?of?a)?collected?and?extended?jog,?b)?collected?and?extended?lope,?c)?injuries,? and?d)?future?research.? ? Collected?and?Extended?Jog? ? The?collected?and?extended?jog?of?stock?breed?western?pleasure?horses?in? the?current?study?was?performed?as?a?four?beat?stepping?gait??in? contrast? to? the? leaping? gait? status? implied? by? breed? association? guidelines.??Horses? exhibited? 190 symmetry?and?a?lateral?footfall?sequence?with?no?period?of?suspension?during? both?the?collected?and?extended?jog.??Additionally,?the?jog?was?performed?with? diagonal?couplets?that?moved?closely?together?in?time?instead?of?diagonal?pairs? as?dictated?by?stock?breed?association?guidelines.??The?extended?jog?did?exhibit? greater?diagonal?synchronization?of?the?diagonal?pairs?than?did?the?collected?jog,? but? failed? to? reach? coincidence.??Periods?of?tripedal?and?quadrupedal?support? found? in? the? collected? and? extended? jog? indicates? that? the? jog? was? performed? with?limited?forward?motion?that?lead?to?a?loss?of?dynamic?stability,?albeit?less?in? the? extended? jog.??Vertical? excursions? of? the? horses? during? the? collected? and? extended? jog? indicated? that? horses? maintained? a? level? topline? throughout? the? gaits.??When?examining?angular?kinematics,?current?stock?breed?western?pleasure? horses?exhibited?similar?joint?motions?for?the?shoulder,?elbow,?carpus,?hip,?stifle,? and?hock?joints?to?the?previously?studied?stock?breed?western?pleasure?horses.?? The?hindlimb?fetlock?joint?indicated?an?extension?peak?during?the?swing?phase?in? earlier?stock?breed?western?pleasure?research?that?was?not?present?in?the?current? study;? further,? both? the? fore? and? hindlimb? fetlock? joint? motions? were? not? as? obvious? in? earlier? stock? breed? western? pleasure? joint? motion? as? in? the? current? study?(Nicodemus?and?Booker?2007).??? ? The?current?study?indicated?results?that?determined?that,?contrary?to?our? hypothesis,? stock? breed? western? pleasure? horses? do? not? alter? stride? length? 191 independently?of?stride?duration?during?the?jog.??The?inverse?relationship?found? among?stride?length,?stride?frequency,?and?velocity?to?stride?duration?indicated? that? horses? did? not? alter? stride? length? independently? of? stride? duration? when? comparing?the?collected?to?extended?jog.??Congruent?with?our?hypothesis,?the? extended?jog?more?closely?followed?the?two?beat?requirement?of?the?jog?set?forth? by?stock?breed?western?pleasure?guidelines?for?gait?performance.??As?well,?horses? followed?breed?guidelines?with?regards?to?performance?of?the?extended?jog?when? compared?to?the?collected?jog?based?on?increases?in?stride?length?and?velocity.?? Horses?? head? carriage? and? topline? did? not,? however,? more? closely? follow? the? guidelines? set? forth? by? major? stock? breed? associations? for? western? pleasure? competition?during?the?extended?jog?as?horses?maintained?a?level?topline?during? both?the?extended?and?collected?jog.??Based?on?the?results?determined?by?this? study,? it? is? proposed? that? stock? breed? associations,? including? AQHA,? APHA,? ApHC,? and? PHBA,? change? the? gait? definition? of? the? jog? to? more? closely? and? completely? identify? the? gait? as? performed? by? stock? breed? western? pleasure? horses.??By? defining? the? jog? as? a? four?beat? stepping? gait? without? visible? separation? of? the? diagonal? pairs,? horses? will? maintain? the? smoothness? desired? during?the?jog?yet?rid?the?definition?of?the?implied?suspension?related?to?a?two? beat?leaping?gait.??? ? ? 192 Collected?and?Extended?Lope? ? ? Horses? performed? all? variations? of? the? lope? as? asymmetrical? four?beat? stepping?gaits?with?leads;?the?left?lead?collected?and?extended?lope?and?the?right? lead? extended? lope? exhibited? a? lateral? footfall? sequence? while? the? right? lead? collected? lope? was? performed? with? a? diagonal? footfall? sequence.??Diagonal? couplets,?instead?of?diagonal?pairs,?were?found?during?the?trailing?forelimb?and? leading?hindlimb?of?the?right?and?left?collected?and?extended?lope?indicating?that? the? diagonally? paired? limbs? moved? closely? together? in? time? but? not? simultaneously.??However,?this?greater?synchronization?of?the?diagonal?pair?was? not?found?in?the?right?lead?extended?lope?and?may?be?related?to??handedness,?? (which?was?not?examined)?of?the?horses.??Tripedal?limb?support,?which?has?been? shown?to?indicate?a?loss?in?dynamic?stability?in?other?breeds?of?horses,?showed? mixed?results?when?moving?from?the?right?and?left?lead?collected?to?extended? lope,? so? without? the? inclusion? of? quadrupedal? limb? support,? it? is? difficult? to? determine? how? dynamic? stability? during? the? lope? is? affected? when? evaluating? limb?support?phases?only.??However,?vertical?excursions?of?the?head?and?croup? indicate?that?horses?did?not?exhibit?a?level?topline?during?the?right?or?left?lead? collected?and?extended?lope,?which?is?a?marker?of?dynamic?stability?and?suggests? that? these? gaits? have? a? great? balance? demand.??When? examining? angular? kinematics? of? leading? limbs? to? previously? studied? loping? stock? breed? western? 193 pleasure?horses?similar?joint?motions?for?the?shoulder,?elbow,?carpus,?hip,?stifle,? and?hock?are?demonstrated.??However,?fore?and?hindlimb?fetlock?joint?motion? was?not?as?clear?in?Nicodemus?and?Booker?(2007)?as?in?the?current?study? The?current?study?determined?that,?contrary?to?the?hypothesis,?stock?breed? western? pleasure? horses? do? not? alter? stride? length? independently? of? stride? duration?during?the?lope.??The?inverse?relationship?found?among?stride?length,? stride? frequency,? and? velocity? to? stride? duration? indicated? that? horses? did? not? alter? stride? length? independently? of? stride? duration? when? comparing? the? collected? to? extended? lope.??Inconclusively,? based? on? the? discrepancies? in? diagonal? synchronization? at? the? extended? lope? it? is? unclear? as? to? whether? the? extended?lope?more?closely?follows?the?guidelines?set?forth?by?major?stock?breed? associations?for?western?pleasure?competition?than?does?the?collected?lope?with? regards? to? the? three?beat? requirement? of? the? lope.??Horses?? head? carriage? and? topline?did?not,?however,?more?closely?follow?the?guidelines?set?forth?by?major? stock?breed?associations?for?western?pleasure?competition?during?the?extended? jog?as?horses?did?not?maintained?a?level?topline?during?either?the?extended?or? collected?lope.??Based?on?the?results?determined?by?this?study,?it?is?proposed?that? stock?breed?associations,?including?AQHA,?APHA,?ApHC,?and?PHBA,?change? the?gait?definition?of?the?lope?to?more?closely?and?completely?identify?the?gait?as? performed? by? stock? breed? western? pleasure? horses? as? well? as? address? topline? 194 carriage.??By? defining? the? lope? as? a? four?beat? stepping? gait? without? visible? separation? of? the? diagonal? pairs,? horses? will? maintain? the? smoothness? desired? during?the?lope?yet?rid?the?definition?of?the?implied?suspension?related?to?a?three? beat?leaping?gait.??In?an?effort?to?address?topline?carriage?stock?breed?associations? should,?theoretically,?continue?to?push?for?more?forward?motion?during?the?lope,? which? should? increase? the? horse?s? balance? and? result? in? a? more? level? topline? during?the?lope.??As?of?yet,?this?described?gait?with?greater?forward?motion?is?not? available? for? study? the? previous? statement? is? hypothetical? and? in? complete? speculation.?? ? Injuries? ? Anecdotally,?the?changes?in?stock?breed?western?pleasure?guidelines?from? 2005? to? the? present? have? reduced? the? injury? and? joint? trauma? rate? of? current? western? pleasure? horses? by? encouraging? horses? to? have? a? natural? stride? of? reasonable?length?and?rewarding?those?horses?with?forward?motion.??The?ability? of?horses?to?hold?a?steady?topline?indicates?that?the?increased?forward?motion,? based?on?an?increase?in?stride?length,?combined?with?the?shift?in?limb?support? phases? decreases? the? balance? challenge? and? increases? dynamic? stability.?? Decreasing? the? challenge? to? the? horses?? balance? thereby? increasing? dynamic? stability?allows?the?horse?to?move?more?naturally?and?reduces?joint?injury?and? 195 trauma.???Thus,?continuing?the?gait?definition?transformation?with?regards?to?the? lope? to? encourage? even? greater? forward? motion? than? was? seen? in? the? present? study?should?theoretically?maintain?the?reduction?in?joint?injury?and?trauma?to? the?stock?breed?western?pleasure?horse.??? ? Future?Research? ? Research?concerning?the?stock?breed?western?pleasure?horse?is?still?limited? in? comparison? to? other? breeds;? therefore,? continuing? research? using? the? stock? breed? western? pleasure? horse? should? examine? the? right? and? left? side? of? the? jogging?horse?for?asymmetry,?continue?defining?the?extended?jog,?compare?the? right?and?left?lead?lope,?further?evaluate?the?collected?and?extended?lope,?and? hold?velocity?constant?to?determine?its?effect?on?stride?length?and?duration.? 196 References? 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Roepstorff,?L.,?Johnston,?C.,?Drevemo,?S.?and?Gustas,?P.?(2002)?Influence?of?draw? reins? on? ground? reaction? forces? at? the? trot.? Equine? Veterinary? Journal,? Supplement?34,?349?352.? ? Rogers,?J.?(2004)?Get?a?move?on.?In:?Paint?Horse?Journal,?American?Paint?Horse? Association,?Fort?Worth.?p?14.? ? Schamhardt,?H.C.,?Van?den?Bogert,?A.J.?and?Hartman,?W.?(1993)?Measurement? Techniques?in?Animal?Locomotion?Analysis.?Cells?Tissues?Organs?146,?123? 129.? ? Splan,? R.K.? and? Hunter,? H.B.? (2004)? Temporal? variables? of? the? canter? of? the? Tennessee?Walking?Horse.?Equine?and?Comparative?Exercise?Physiology?1,?41? 44.? ? Thomas,?H.S.?(2005)?The?Horse?Conformation?Handbook,?Storey?Publishing,?North? Adams.?p?387.? ? Waldern,?N.M.,?Wiestner,?T.,?von?Peinen,?K.,?Gomez?Alvarez,?C.G.,?Roepstorff,? L.,? Johnston,? C.,? Meyer,? H.? and? Weishaupt,? M.A.? (2009)? Influence? of? different? head?neck? positions? on? vertical? ground? reaction? forces,? linear? and? time? parameters? in? the? unridden? horse? walking? and? trotting? on? a? treadmill.?Equine?Veterinary?Journal?41,?268?273.? 203 ? Weishaupt,?M.A.,?Bystr?m,?A.,?von?Peinen,?K.,?Wiestner,?T.,?Meyer,?H.,?Waldern,? N.,? Johnston,? C.,? van? Weeren,? R.? and? Roepstorff,? L.? (2009)? Kinetics? and? kinematics?of?the?passage.?Equine?Veterinary?Journal?41,?263?267.? ? Williams,?D.?(2004)?Interpreting?the?new?western?pleasure?lingo.?In:?Paint?Horse? Journal,?American?Paint?Horse?Association,?Fort?Worth.?p?14.? ? Zips,?S.,?Peham,?C.,?Scheidl,?M.,?Licka,?T.?and?Girtler,?D.?(2001)?Motion?pattern?of? the?toelt?of?Icelandic?horses?at?different?speeds.?Equine?Veterinary?Journal,? Supplement?33,?109?111.? ? ? 204 Appendix?A? ? Form?A.1? ? ? ? OWNER/AGENT?CONSENT?FORM? for?a?Research?Study?Entitled? ?Comparison?of?stride?kinematics?of?the?collected?and?extended?walk,?? jog,?and?lope?of?the?stock?breed?western?pleasure?horse?? ? DEPARTMENT?OF?KINESIOLOGY? COLLEGE?OF?EDUCATION? AUBURN?UNIVERSITY? ? 1.? Project?Director:?? Wendi?H.?Weimar,?PhD????Joanna?E.?Shroyer? Principal?Investigator????Lead?Graduate?Student? Associate?Professor,?Sport?Biomechanics?Laboratory?Director?? Department?of?Kinesiology? ????????2050?Memorial?Coliseum? Auburn,?AL??36849? 334.844.1468? ? 2.? Purpose?of?the?Research:??The?purpose?of?this?research?is?to?determine?the? temporal,? linear,? and? angular? kinematics? of? the? stock? breed? western? pleasure?horse?s?walk,?jog,?and?lope.??? ? 3.? Procedures?for?the?Research:??Animals?considered?for?this?study?must?be? stock? breed? western? pleasure? horses? whom? are? in? current? western? pleasure?training?or?competition.??Upon?agreeing?to?participate?you?will? 205 sign? the? client? consent? form? and? mount? and? warm? up? your? horse? in? preparation?for?data?collection.??After?warming?up,?anatomical?landmarks? of?the?horse?will?be?marked?with?47?retroreflective?markers.??Then?you?will? rider? your? horse? through? the? capture? volume? at? the? collected? and? extended?walk,?jog,?and?lope.??A?minimum?of?three?trials?per?gait?will?be? required?then?your?responsibilities?as?a?participant?in?this?study?will?be? completed.??Appointments?may?be?made?by?contacting?the?lead?graduate? student,?Joanna?E.?Shroyer?at?334.844.1468.? ? 4.? Potential?Risks?or?Discomforts:??There?are?minimal?risks?of?injury?to?the? horse?associated?with?participation?in?this?study,?but?no?more?than?when? the?horse?is?ridden?normally.??? 5.? Potential?Benefits:??Direct?benefits?to?the?patient?include?knowing?how? their? stock? breed? western? pleasure? horse? performs? the? collected? and? extended?walk,?jog,?and?lope?with?relation?to?stride?length?and?duration,? velocity,?footfall?sequence,?and?joint?angles.? 6.? Financial?Considerations?for?Participation?in?the?Study:??There?will?be?no? compensation?for?your?participation?in?this?study.??There?are?no?financial? obligations? by? the? owner? to? Auburn? University? for? participation? in?this? study.? 7.? Additional?Expenses?Expected?for?Participation?in?the?Study:??You,?as? the? owner,? are? financially? responsible? for? costs? associated? with? the? treatment?of?complications?or?accidental?injury?associated?with?this?study.??? ? 8.? Client?Consent:??I?understand?that?I?am?free?to?withdraw?my?consent?and? discontinue?participation?in?this?research?project?at?any?time?without?this? decision?affecting?my?animal?s?medical?care.?? ? I?also?understand?that?Auburn?University?will?protect?the?confidentiality? of?my?records?to?the?extent?provided?by?Law.??All?videotapes?recorded? during?data?collection?will?be?destroyed?after?data?extraction.? ? 9.? Signatures:??I?have?fully?explained?to?___________________________?the? nature? and? purpose? of? the? above?described? procedure? and? the? benefits? and?risks?that?are?involved?in?its?performance.??I?have?answered?and?will? answer?all?questions?to?the?best?of?my?ability.??I?may?be?contacted?at?the? following?telephone?number:??_________________.? ? 206 ___________________________________?? _____________________? Signature?of?Principal?or?Co?Principal?? Date? Investigator?Obtaining?Consent?? ? I? have? been? fully? informed? of? the? above?described? procedure? with? its? possible?benefits?and?risks?and?I?have?received?a?copy?of?this?description.??I? certify? that? I? am? the? legal? owner? (or? agent? of? the? owner)? of,? and? am? responsible?for,?this?animal.??I?permit?my?animal?s?participation?in?this?study.? ? ? ___________________________________?? _____________________? Signature?of?Agent/Owner????Date? ? ___________________________________?? ? Street?Address?of?Agent/Owner? ? ___________________________________? City,?Zip? ?? 207 Form?A.2? ? ? ? EQUINE?INFORMATION?FORM? for?a?Research?Study?Entitled? ?Comparison?of?stride?kinematics?of?the?collected?and?extended?walk,?? jog,?and?lope?of?the?stock?breed?western?pleasure?horse?? ? DEPARTMENT?OF?KINESIOLOGY? COLLEGE?OF?EDUCATION? AUBURN?UNIVERSITY? ? Project?Directors:?? Wendi?H.?Weimar,?PhD????Joanna?E.?Shroyer? Principal?Investigator????Lead?Graduate?Student? Associate?Professor,?Sport?Biomechanics?Laboratory?Director?? Department?of?Kinesiology? ???????????2050?Memorial?Coliseum? Auburn,?AL??36849? 334.844.1468? ? Equine?Name:?_________________________________________________________? Year?Foaled:??_______??Sex:??M????G????S???Height:??_______??Weight:??_______?? Breed?Registry:??AQHA? PHBA????????APHA???????Color:??______________________? Years?of?WP?Competition:??___________?????????Years?of?WP?Training:??__________? Awards/Points/Championships:??_________________________________________? ________________________________________________________________________ ________________________________________________________________________? What?type?of?bit?does?your?horse?show?in???________________________________? Subject Number: _____ 208 Shoeing:? Is?your?horse?shod???? Front?(Y?/?N)?? Back?(Y?/?N)? Type?of?Shoe? Front?____________________? Back??__________________? Where?is?your?horse?in?his/her?shoeing?cycle???_____________________________? Does?your?horse?have?any?other?shoeing?concerns?we?should?know?about??If? so,?what?are?they??_______________________________________________________? _______________________________________________________________________? General?Health:? Has?your?horse?seen?the?veterinarian?in?the?last?week???If?yes,?why???_________? _______________________________________________________________________? When?were?your?horse?s?last?joint?injections???______________________________? ? Joints?Injected:? Hock?(R?/?L)?? ? Stifle? (R?/?L)?? ? Coffin?(F??/?H?)?(R?/?L)?? Fetlock?(F?/?H)?(R?/?L)? Other:??__________? ? Does?your?horse?have?any?ongoing?health?concerns???If?so,?please?state?health? concern.??_______________________________________________________________? ________________________________________________________________________? ? Is?there?anything?else?we?should?know?about?the?health?of?your?horse???If?so,? please?explain.??_________________________________________________________? ________________________________________________________________________? ________________________________________________________________________? Do?you?know?of?any?reason?why?your?horse?may?not?be?able?to?successfully? complete?the?required?tasks???____________________________________________? ________________________________________________________________________? ? This?horse?has?been?designated?as??healthy??for?the?purpose?of?this?research? project?by?Robert?Gillette,?DVM.?