PLASMA MYOSIN AND CREATINE-KINASE TIME-COURSE AFTER A CONCENTRIC-ECCENTRIC FIELD EXERCISE

The effect of a concentric (uphill run)-eccentric (downhill run)field exercise of 22.3 km long was examined in five healthy male volunteers to compare the time course of changes in plasma creatine kinase (CK) a ctivity and beta myosin heavy chain (beta MHC) concentration observed during the recovery. CK and beta MHC were examined in blood sampled be fore exercise, immediately and 5 hours after exercise ceased. Screenin gs were conducted 1, 2, 3, 4, 5 and 7 days later. For every subject, t he peak of plasma CK was transient and observed within the first 24 ho urs of recovery. In contrast to CK changes, plasma beta MHC elevation was delayed and the peak, also transient, was observed the second or t he third day after the exercise. The highly significant relationship b etween individual values of CK and beta MHC (P<0.001) demonstrates tha t beta MHC could be used as a marker of skeletal muscle damage after a cute exercise.