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Full-Text Articles in Life Sciences
Age-Related Changes In Corticospinal Drive During Locomotor Adaptation, Sumire D. Sato
Age-Related Changes In Corticospinal Drive During Locomotor Adaptation, Sumire D. Sato
Doctoral Dissertations
During activities of daily living, locomotor patterns must be continuously adapted according to changes in our body (e.g., bodily injuries, fatigue) and to the changing environment (e.g., walking surface). Plasticity of spinal networks and supraspinal centers, including the cerebellum and cerebral cortex, have been shown to play important roles in human locomotor adaptation. However, the neural control of locomotion and the ability to adapt locomotor patterns are altered in older adults, which may limit activities of daily living and increase fall-related injuries in the elderly population. My dissertation project is focused on understanding the role of corticospinal drive during split-belt …
Bioenergetic Mechanisms Of Age-Related Differences In Muscle Fatigue, Liam F. Fitzgerald
Bioenergetic Mechanisms Of Age-Related Differences In Muscle Fatigue, Liam F. Fitzgerald
Doctoral Dissertations
Muscle fatigue is defined as the reduced capacity to produce torque or power in response to contractile activity. Previous work has observed greater fatigue in older than young adults in response to high-velocity contractions, but similar fatigue with age in response to moderate-velocity contractions. The mechanisms for these age-related differences is not clear. One potential explanation is a greater accumulation of putative agents of fatigue (e.g., Pi, H2PO4-, and H+) in older than young muscle during high- but not moderate-velocity contractions. Older muscle may accumulate these metabolites to greater extent because of deficits …
Recovery From Muscle Fatigue In Young And Older Adults: Implications For Physical Function, Stephen A. Foulis
Recovery From Muscle Fatigue In Young And Older Adults: Implications For Physical Function, Stephen A. Foulis
Open Access Dissertations
As adults age, skeletal muscles become smaller and weaker, which can ultimately lead to declines in physical function and disability. In general, older adults produce less isometric force and dynamic power than younger adults. The effects of this weakness are amplified following a series of muscle contractions that result in muscle fatigue. Since daily routines consist of repeated series of activity followed by rest, it is important to understand how muscle recovers from fatigue. In particular, muscle power has been shown to be related to physical function and balance. Thus, understanding the process of recovery from muscle fatigue will help …
Optimal Control Of Human Running, Ross Herbert Miller
Optimal Control Of Human Running, Ross Herbert Miller
Open Access Dissertations
Humans generally use two modes of locomotion as adults. At slow speeds we walk, and at fast speeds we run. To perform either gait, we use our muscles. The central questions in this dissertation were: (1) Why do humans run the way they do, and (2) How do the mechanical properties of muscle influence running performance? Optimal control simulations of running were generated using a bipedal forward dynamics model of the human musculoskeletal system. Simulations of running and sprinting were posed as two-point boundary value problems where the muscle excitation signals were optimized to maximize an optimality criterion. In the …