Abstract des Autors

To determine the incidence and range of serum creatine kinase MB (CK-MB) isoenzyme activity after ultra-marathon running, a popular test kit was used to measure total serum creatine kinase (CK) and CK MB-activity in 75 athletes immediately after they had completed an 88-km running race. Total serum CK activity was markedly elevated after the race and 45 (60 ) runners showed abnormal CK-MB isoenzyme activities (greater than 4 of total CK activity range 1-19 ). Electrophoresis of 31 sera with either CK-MB to total CK activity greater than 854 U/l showed that 31 (100 ) had visible CK-MM bands, 21 (68 ) had visible CK-BB bands, but only 14 (44 ) had visible CK-MB bands. We conclude that prolonged exercise increases the serum activity of all three CK-isoenzymes, and that the CK-Mb test kit used in this study identified a greater number of sera with elevated post-race CK-MB isoenzyme activity than did electrophoresis. This discrepancy could result either from cross-reaction of elevated CK-BB activity with the test kit, or from relative insensitivity of the electrophoresis. The tissue source and long-term significance of the elevated serum CK-Mb and CK-BB isoenzyme activity induced by ultra-marathon running are uncertain.