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Full-Text Articles in Life Sciences

Genes With Physiological Roles In Callipyge Muscle Hypertrophy, Hui Yu Oct 2013

Genes With Physiological Roles In Callipyge Muscle Hypertrophy, Hui Yu

Open Access Dissertations

Callipyge sheep is an excellent model to study genes regulation in muscle growth since the up-regulation of DLK1 and/or RTL1 results in extreme postnatal muscle hypertrophy in loin and hindquarters. DLK1 and/or RTL1 are the primary inducers of muscle hypertrophy due to the inheritance model for the callipyge phenotype. The overall aim of this dissertation is to study the physiological pathways responding to the up-regulation of DLK1 and / or RTL1 in the hypertrophied muscles. Microarray analysis of gene expression identified 375 genes that were differentially expressed in callipyge semimembranosus. Twenty-five transcripts were further verified by quantitative PCR in two …


Recovery From Muscle Fatigue In Young And Older Adults: Implications For Physical Function, Stephen A. Foulis Sep 2013

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 May 2011

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 …