Light concentric exercise during recovery from exercise-induced muscle damage

Eight male volunteers performed two eccentric exercise bouts using the forearm flexors of first one arm, then the other. The two bouts, consisting of 70 maximum voluntary muscle actions, were separated by a period of three weeks. In the experimental condition of the study, five sets of 10 sub-maximal concentric muscle actions were performed on the four days after the eccentric bout. In the control condition of the study, no concentric work was performed. Repeated measures analysis of variance indicated an increase in serum creatine kinase activity (p <0.01) and decreases in relaxed elbow angle (p <0.05) and maximum voluntary contraction force (p <0.01) at three elbow angles (0.87, 1.57 and 2.79 rad) after both eccentric bouts. However, the serum creatine kinase response to eccentric exercise was reduced in the experimental condition (p <0.05) and recovery of maximum voluntary force production at the most acute joint angle (0.87 rad) was accelerated (p <0.01). Although muscle soreness increased after both eccentric bouts (p <0.05; Wilcoxon test), further concentric exercise evoked temporary relief of muscle soreness two days after the bout (p <0.05; Wilcoxon test). However, light concentric work had no effect on the other parameters monitored. In practical terms, these results suggest that the therapeutic effects of light concentric work on correlates of exercise-induced muscle damage are minimal.