EXSS1029 Lecture Notes - Lecture 8: Physiological Cross-Sectional Area, Hypertrophy, Myofibril

• School: University of Sydney
• Department: Exercise and Sport Science
• Course: EXSS1029
• Professor: Dr Tom Gwinn

Document Summary

Specifically through changes in fiber area (not fiber number) Direct measurement removal of muscle from the body and weighing it (animals or cadavers) Estimate of muscle volume: non-invasive through sequential imaging techniques (mri, ct scan) Comparing/calculating volume of the muscle (cubic centimeters) Measuring changes in lean body mass using dxa (whole body bone, fat, lean tissue mass) Can also measure regional lean tissue mass. Estimate changes in muscle area by measuring fiber area. Done using biopsy needle needle pushed into muscle belly > cutting of portion of soft tissue. 150-300 fibres thin slice taken and viewed to measure individual fiber area = mean fiber area. Increase in physiological cross sectional area (cross sectional growth) = increase in average fiber length (longitudinal growth) Structural measure relating to muscle force developing capacity. Male average growth 60% greater than females (although percentage growth is similar) Causes of hypertrophy: increase in rate of protein synthesis (rate of myosin/actin synthesis)