Kinetics and Cognition in Aging Gait: The Role of Executive Function and Running Experience

Abstract

Background: Aging is associated with a characteristic reorganization of lower limb biomechanics during gait, known as the distal-to-proximal shift, where ankle power generation decreases while hip power increases. While traditionally viewed as compensation for peripheral neuromuscular changes, emerging evidence suggests this shift may reflect central nervous system adaptations influenced by cognitive-motor interactions. However, traditional biomechanical measures (A2/H3) are confounded by walking speed, limiting our understanding of true age-related neuromuscular changes and their relationship to cognitive function. Purpose: This dissertation: (1) Measured the role of executive function and cognitive load on the distal to proximal shift in joint power that occurs with aging and (2) determined whether lifelong running preserves cognitive-motor integration during dual-task walking in older adults. Methods: 58 participants (22 young adults 18-35 years, 22 older adult nonrunners aged 60 and above, with an additional 14 older runners aged 60 and above) completed comprehensive gait analysis under single and dual-task conditions (verbal fluency) using 3D motion capture and force plates. Executive function was assessed through standardized cognitive batteries. Novel collision phase power measures (H1/K1) capturing collision dynamics were compared with traditional A2/H3 propulsive measures across multiple walking speeds. Significance: This research established speed-stable biomarkers for clinical assessment of age-related mobility decline, elucidated the neuromechanical mechanisms underlying the distal-to-proximal shift, and identified whether exercise-related protection extends beyond physical to cognitive-motor domains. These results inform targeted interventions addressing both biomechanical and cognitive aspects of mobility preservation in aging populations.