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Full-Text Articles in Life Sciences
Role Of Fat Content On The Structure And Function Of Human Skeletal Muscle, Joseph A. Gordon Iii
Role Of Fat Content On The Structure And Function Of Human Skeletal Muscle, Joseph A. Gordon Iii
Doctoral Dissertations
Muscle size does not fully explain variations in muscle strength. Fat content has been implicated in muscle weakness, though this relationship remains unclear. The relationship between fat and strength may vary between scales (e.g., cellular, organ, and organism). The goal of this dissertation was to clarify the role of fat in the structure and function of muscle using in vitro and in vivo techniques across multiple scales in adults 21-45 years old. Study 1 tested the agreement of intramyocellular lipid (IMCL) content between oil red o (ORO) and magnetic resonance spectroscopy (MRS) techniques. These measures of IMCL were also compared …
Link Between Muscle And Whole-Body Energetic Responses To Exercise, Christopher M.T. Hayden
Link Between Muscle And Whole-Body Energetic Responses To Exercise, Christopher M.T. Hayden
Masters Theses
Substantial evidence exists regarding how skeletal muscles use energy and how this affects muscular performance. What remains unclear is how characteristics of muscle energetics affect whole-body energetics during daily living, and what effects this may have on mobility. The goal of this study was to determine the associations between muscle and whole-body energetics including the relationships between: 1) muscle PCr depletion (∆PCr) in response to light intensity isotonic contractions and the oxygen deficit at the onset of a 30-min treadmill walk (30MTW), and, 2) muscle oxidative capacity and excess post-exercise oxygen consumption (EPOC; 30MTW), respiratory exchange ratio (RER; 30MTW), and …
Mechanisms That Limit Oxidative Phosphorylation During High-Intensity Muscle Contractions In Vivo, Miles F. Bartlett
Mechanisms That Limit Oxidative Phosphorylation During High-Intensity Muscle Contractions In Vivo, Miles F. Bartlett
Doctoral Dissertations
Skeletal muscle oxidative capacity plays a critical role in human health and disease. Although current models of oxidative phosphorylation sufficiently describe skeletal muscle energetics during moderate-intensity contractions, much is still unknown about the mechanisms that control and limit oxidative phosphorylation during high-intensity contractions. In particular, the oxygen cost of force generation is augmented during exercise at workloads above the lactate threshold. Presently, it is unclear whether this augmentation in muscle oxygen consumption is driven by increased rates of oxidative ATP synthesis (ATPOX) or by decreases in the efficiency of ATPOX due to mitochondrial uncoupling. To address this …
Tropomyosin-Based Effects Of Acidosis On Thin-Filament Regulation During Muscle Fatigue, Brent Scott
Tropomyosin-Based Effects Of Acidosis On Thin-Filament Regulation During Muscle Fatigue, Brent Scott
Masters Theses
Skeletal muscle fatigue is defined as a loss in the force/velocity generating capacity of a muscle. A portion of the loss in function is attributable to effects of acidosis (i.e. low pH) on the regulatory proteins, troponin and tropomyosin (Tm), which regulate the binding of myosin and actin in a calcium (Ca++) dependent manner. However, the relative role of troponin and Tm on myosin-actin function during acidosis is not clear, nor are the mechanisms underlying these effects. PURPOSE: To determine the role of Tm in the acidosis-induced depression of muscle function using isolated muscle proteins in an in …
Changes In Muscle Control And Coordination In Novel Task Learning, Sangsoo Park
Changes In Muscle Control And Coordination In Novel Task Learning, Sangsoo Park
Doctoral Dissertations
Learning many daily life motor skills is critical for survival and the quality of living in humans. As children, we develop walking and running patterns to move the body from point A to B without falling, and we learn to grasp a wide variety of objects during activities of daily living. Motor skills can be properly performed by appropriate muscle activations which are controlled by the central nervous system. How does the central nervous system develop and fine-tune its control strategy to learn a new motor skill? The aim of this dissertation was to better understand how human participants alter …
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 …