Evaluation of exercise-induced muscle damage by surface electromyography.

OBJECTIVE

To investigate the feasibility of a non-invasive and instant method to evaluate the degree of exercise-induced muscle damage.

METHODS

Thirteen male college athletes (23.4±1.0year, 180.03±3.51cm, 75.93±6.70kg) took part in the trial. Measures included serum creatine kinase (CK) after eccentric and endurance exercise, and surface electromyography (sEMG) during knee extension and flexion on a Biodex unit. Relation analysis was employed between sEMG and serum CK after the eccentric and endurance exercise.

RESULTS

There were positive correlations between serum CK at 24 and 48h after eccentric exercise and the AREA of sEMG for the slow isokinetic contraction before eccentric exercise (r=0.69, P<0.01 and 0.64, P<0.05, respectively). The zero crossing rate (ZCR) immediately after exercise was negatively correlated with serum CK at 48h after exercise for the slow and fast tests (r=-0.63 and -0.59, P<0.05, respectively). Mean power frequency (MPF) and ZCR of sEMG at 6h post endurance exercise were positively correlated with serum CK at 24h (r=0.73 and 0.69, P<0.05, respectively) for the fast isokinetic test.

CONCLUSIONS

Exercise-induced muscle damage as evaluated by serum CK was associated with the AREA of sEMG after eccentric exercise. The ZCR of sEMG was a good predictor of muscle damage after endurance exercise.