This Is AuburnElectronic Theses and Dissertations

Skeletal Muscle Growth Responses to Voluminous Resistance Training in Young Men with or without Graded Dosage of Protein Supplementation




Haun, Cody

Type of Degree

PhD Dissertation




Purpose: We examined hypertrophic outcomes of weekly graded whey protein dosing (GWP) versus whey protein (WP) or maltodextrin (MALTO) dosed once daily during 6 weeks of resistance training (RT). Methods: College-aged resistance-trained males (training age=5±1 yrs; mean±SE) were assigned to WP (25g/d; n=10), MALTO (30g/d; n=10), or GWP (25-150 g/d from weeks 1-6; n=11). RT occurred 3d/wk (2 upper- and 2 lower-body exercises/d, 10 repetitions/set), and RT volume increased from 10 sets/exercise (week 1) to 32 sets/exercise (week 6). The 6-week RT program implemented was designed to involve higher RT volumes than ever investigated in this timeframe. Tests performed prior to training (PRE) and after weeks 3 (MID) and 6 (POST) included dual-energy x-ray absorptiometry (DXA), vastus lateralis (VL) and biceps brachii ultrasounds, and bioelectrical impedance spectroscopy (BIS). VL biopsies were also collected for immunohistochemical staining. Repeated-measures ANCOVAs were performed, although emphasis was also placed on effect size calculations. Results: The GWP group experienced the greatest PRE to POST reduction in DXA fat mass (FM) (-1.00 kg, d=- 0.24, p<0.05) and increase in DXA lean body mass (LBM) (+2.93 kg, d=0.33, p<0.05). DXA LBM increases (ΔLBM) occurred from PRE to MID (+1.34 kg, p<0.001) and MID to POST (+0.85 kg, p<0.001) across all groups. However, when adjusting ΔLBM for extracellular water changes, a significant increase occurred from PRE to MID (+1.18 kg, p<0.001), but not MID to POST (+0.25 kg; p=0.131). Conclusions: Larger effects on FM and LBM in GWP subjects indicates a need for longer-term investigations with greater sample sizes examining graded WP intakes and RT. Additionally, ECW-corrected LBM gains were largely dampened, but still positive, in resistance-trained subjects when RT exceeded ~20 sets/exercise/wk.