Regulation of human skeletal muscle adaptation to exercise training

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The breakdown of fuels such as carbohydrates and fats for energy involves a complex series of metabolic reactions. Precise regulation of these various metabolic pathways is vital to the integrity of the cell and organism. My research proposal is designed to investigate the regulation of energy metabolism in skeletal muscle and in particular the mechanisms that coordinate "remodeling" of this tissue in response to acute and chronic contraction. Skeletal muscle is a very interesting tissue to study since it can change its metabolic rate quite dramatically. For example, during strenuous exercise the rate of energy demand can increase by over a hundred-fold compared to rest, which forces the muscle to rapidly adjust its rate of energy supply in order to maintain proper function. The way in which I study skeletal muscle in humans is to produce distinct "metabolic challenges" by asking people to exercise at different workloads for varying periods of time. We can further investigate metabolic processes by altering substrate availability (e.g., using dietary manipulations) or by studying subjects with special characteristics (e.g., highly trained individuals). We investigate the muscle response by obtaining small samples of tissue using the needle biopsy technique. The tissue is then analyzed for compounds such as enzymes and other proteins that are involved in regulating cellular energy metabolism. We are particularly interested in the fact that short bursts of very intense exercise appear to stimulate metabolic adaptations that are typically associated with prolonged endurance-type training despite. However, the molecular signals that regulate adaptation to these diverse stimuli are unknown. The major goal of this research is to provide basic scientific information about metabolic regulation, but the results may have practical implications for people who are interested in the body's response to exercise.