Abstract

The elevation of creatine kinase levels after exercise has been postulated to be related to duration and intensity of exercise, type of activity, and fitness of the individual. Limited data exist on creatine kinase levels in individuals training and competing over an extended period of time. Creatine kinase (normal values 40-200 U/l) was measured in competitive swimmers during aseason of training and competition. There was a 60 increase in the creatine kinase levels from early November (mean 280 U/l) to peak training levels in January (mean 448 U/l). During the tapering phase of the season (March), before the national championships, a significant decrease (0.01) was seen (mean 191 U/l) from the high in January. As training distance increased, the serum levels of creatine kinase increased, and during the tapering phase, in which distance decreased but training intensity increased, they remained on the high-normal level. It is concluded that the creatine kinase levels are elevated as part of athletic training and that they form a sensitive index of exercise stress and training distance and may not indicate muscle damage or injury. Verf.-Referat