Mechanisms of muscle fatigue.

The concept of muscle fatigue as a factor limiting muscle performance has evolved into one in which fatigue is avoided in order to protect the muscle from injury induced by over stimulation. No one mechanism accounts for all the changes in muscle performance occurring during fatigue. Research on pathophysiological factors limiting force production or shortening capacity during the fatigue process has widened to detailed electrophysiologic, metabolic and molecular aspects. All are extensively reviewed in the present paper. The known mechanisms are likely to be interdependent, synergistic, and integrated. A careful interpretation of individual research is implied, particularly when data from experimental animal models are translated to human beings.