Exercise Induced Myopathys

Muscle damage and myopathy-like changes can occur following strenuous and unccustomed exercise, particularly activity involving eccentric contractions. The associated strength loss can have a long lasting impact on performance. The question of how eccentric contraction induced injury effects muscle performance and what mechanism(s) account for the strength loss is addressed in this review by focusing attention on the changes in activation and mechanical properties of the muscle. We also describe an animal model developed in our laboratory that creates a standardized stretch injury in order to understand the more about the pathophysiology of the so-called ‘muscle strain injury’. Recent data question the exact role of inflammation and invading leukocytes in the repair process. Changes in single fiber mechanics and alteration in contractile protein expression may have implications for understanding the regulation of muscle injury and repair.