Neuromuscular irritability and serum creatine phosphate kinase in athletes in training.

Abstract

Athletes in training were examined at rest for serum creatine phosphate kinase (CPK) and irritability of the quadriceps muscles vastus medialis and rectus femoris. The irritability of the former shows a significant correlation with that of various other phasic muscles of the extremities. A significantly higher serum CPK-activity was found in athletes with hyperexcitability of the phasic muscles for rheobasic stimuli. The possible origin of the high resting level of CPK in athletes, as well as the characteristics of the investigated muscles, are discussed.