Effect of eccentric exercise on neuromuscular function of the biceps brachii

This study investigated the effects of a bout of exercise-induced muscle damage on strength and motor skill of the elbow flexor muscles. Eight subjects performed 35 maximal isokinetic eccentric elbow flexions at 90 degrees per sec and maximal voluntary contraction (MVC) force, surface electromyography (EMG), plasma creatine kinase (CK) and tracking error associated with a one-dimensional elbow flexion/extension visuomotor pursuit task were studied at intervals up to 28 days after exercise. Subjects showed a post-exercise decline in MVC (mean = 63+/- 11%(s.d.) of pre-exercise after 1 day, p<0.02) and were still significantly weaker at 21 days. The delayed-onset plasma CK rise and the absence of any quantitative change in surface EMG sugest that the observed weakness was related to muscle fibre damage. Tracking performance decreased in all subjects with the greatest tracking error occurring 1 day post-exercise (mean = 127% +/- 20% of control value, p