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.
Key words
Eccentric exercise - skeletal muscle damage - further exercise
