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) activity and β myosin heavy chain (β MHC) concentration observed during the recovery. CK and β MHC were examined in blood sampled before exercise, immediately and 5 hours after exercise ceased. Screenings were conducted 1, 2, 3, 4, 5 and 7 days later. For every subject, the peak of plasma CK was transient and observed within the first 24 hours of recovery. In contrast to CK changes, plasma β MHC elevation was delayed and the peak, also transient, was observed the second or the third day after the exercise. The highly significant relationship between individual values of CK and β MHC (P<0.001) demonstrates that β MHC could be used as a marker of skeletal muscle damage after acute exercise.