Influence of muscle power on aerobic performance and the effects of training.

This paper reviews briefly the authors' experience with a short (30 s) maximal isokinetic cycling test in which peak and average power, the decline in power during the test (fatigue index, FI), and the total work accomplished are measured by a computer assisted technique. In an untrained population, the power variables and total work were linearly related to height and lean thigh volume and decline with age; the FI was less in subjects who took part in regular leisure activity. A close linear relationship was found between the total work in 30 s and maximal oxygen intake (VO2 max). The method was applied to studies of the effects of endurance exercise in sedentary young and old men and in patients with coronary artery disease. In the young and old men training increased VO2 max by 28% and 38% respectively, with no change in isokinetic power measurements in the young, but increases of 12% in total work in 30 s in the old. In cardiac patients, reductions in initial VO2 max were greater than in the isokinetic test variables. Control subjects showed reductions in maximal 30 s performance after the study period (12 wk) with no change in VO2 max. Exercised subjects increased VO2 max by 18.5% with variable changes in 30 s performance. There is a close link between maximal short-term muscle capacity and VO2 max in healthy subjects. VO2 max may be increased by training, but this may or may not be accompanied by increases in maximal short-term capacity, presumably depending on the mechanisms that are limiting in any given case.