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December 10, 1982

Creatine Kinase Activity Following Strenuous Exertion-Reply

JAMA. 1982;248(22):2972. doi:10.1001/jama.1982.03330220017018

In Reply.—  The values for total CK activity observed by Brown et al are consistent with the prerace and postrace serial values for total CK activity reported by us in a group of marathon runners.1 We observed a mean postrace total creatine kinase level of 3,424 units/L in 15 runners after the 1979 Boston Marathon.1 These samples were obtained roughly 24 hours after the completion of the race, which corresponded to the peak values as determined in a subgroup of subjects tested more frequently.The postrace peaks in total serum CK activity ranged widely from twice that of normal (319 units/L) to almost 100 times normal (9,260 units/ L). The extraordinarily high values seemed to cluster in high-achieving recreational-type runners who had undertrained in terms of weekly mileage for the maximal effort expended in the race. These values represent considerable transient exertional rhabdomyolysis, with persistent abnormal creatine kinase