Electronic Theses and Dissertations





Document Type


Degree Name

Master of Science


Exercise and Sport Science


Aging is associated with a decline in physical function, cardiovascular health and quality of life. Running promotes better cardiovascular health and has positive effects on the musculoskeletal system in older adults. However, older adults have lower ankle moments and positive powers during running, and exhibit changes in plantarflexor morphology than young adults. These age-related changes contribute to slower running speeds and reduced movement intensity that could influence cardiovascular health. Since older runners who run as much as younger runners exhibit youthful ankle mechanical outputs, running exposure may preserve the locomotor factors that mediate movement speed. The purpose of this study was to compare ankle mechanical output during running and plantarflexor morphological characteristics between older runners who have low or high lifetime running exposure. Twelve older runners with low lifetime running exposure and eight older runners with high lifetime running exposure performed over-ground running trials at 2.7m/s (?5%) while kinematic and ground reaction force (GRF) data were collected. Joint moments and powers were computed using kinematic and GRF data. Right medial gastrocnemius morphological characteristics were assessed using ultrasonography at rest and during isometric contractions. Ankle moments and powers, and plantarflexor morphology were compared between groups using independent t-tests and Coheńђةs d effect sizes. Older runners with different lifetime running exposures ran with similar ankle mechanical output (i.e. no effect of running exposure) (p>0.05). However, older runners with high lifetime exposure ran with greater hip concentric power (p<0.01, d=1.16), despite similar hip extension torques (p<0.05). Plantarflexor morphological characteristics were similar between lifetime running exposure groups. The findings from this study demonstrate that lifetime running exposure does not influence ankle mechanical output or plantarflexor morphology in older runners but that high lifetime running exposure may lead to greater concentric hip joint involvement during running.


Data is provided by the student

Library Comment

Dissertation or thesis originally submitted to the local University of Memphis Electronic Theses and dissertation (ETD) repository