ABSTRACT
It should also be acknowledged that movement does not always occur during maximal-intensity exercise. The scrum in rugby and maintenance of the crucifi x and balance in gymnastics are examples where maximal force production can occur during isometric muscle activity. Durations of exercise are short and range from approximately 1-2 seconds in discrete activities like the shot putt and golf swing to 20-45 seconds of sprinting during running and cycling. Even in these latter activities, there is probably an element of pacing rather than genuinely all-out effort. Also, associated mechanisms of energy release are predominantly anaerobic but they are not exclusively so. During 30 s of ‘fl at-out’ cycling for example, 13-29% of energy provision could come from aerobic sources (Inbar et al. 1976; Bar-Or, 1987).
