PEDS200 Lecture : Neuromuscular System Part 2

• School: University of Alberta
• Department: Physical Education and Sport
• Course: PEDS200
• Professor: Dan Syrotuik

Document Summary

Can muscle motor units and fiber types be converted? y although mu s cannot completely convert (ex. Ft fibers become more oxidative and fatigue resistant with aerobic training) Effect of disuse on muscle y muscle atrophies (reduced csa) y muscle fiber type profile shifts from to y muscle oxidative capacity is reduced. What happens to muscle as we age? y decrease in muscle fiber size especially ft y mn necrosis (cell death) leading to muscle fiber necrosis especially ft y. Increase in muscle connective tissue and fat content y. Due to reduced number of motor units y decrease in overall metabolic activity. Research findings y macdougall: showed a similar number of muscle fibers in bicep muscle of builders compared to untrained. Took biopsy and ct scan of biceps brachii (bb) of body builders and controls. There is mostly hypertrophy when someone is getting bigger. Possible hyperplasia mechanisms muscle fiber splitting, muscle satellite cell incorporation.