Investigation of muscle damage and emg responses during the recovery period following resistance exercises done with isometric, concentric and eccentric contractions

The aim of this study was to investigate the muscle damage and EMG responses during the recovery period following resistance exercises done with isometric, concentric and eccentric contractions.Fifteen soccer players [( ±SS) age: 22,4±2,52yr; body mass: 70,18±9,43kg; height: 173,53±5,30cm] participated in this study as volunteer. In the first phase; in order to evaluate the recovery period following one set maximum loading resistance exercise, concentric (85% of 1 repetition maximum) and eccentric (115% of 1 repetition maximum) exercises were performed 10 repetition and isometric (85% of 1 repetition maximum) exercises were done as long as the subject maintained the contraction. Pre and post-exercise (8-minute course with one minute intervals) EMG activity was recorded from M.Vastus Medialis and M.Rectus Femoris. In phase 2, in order to evaluate the recovery period after muscle damage exercise, concentric (70% of 1 repetition maximum) and eccentric (100% of 1 repetition maximum) exercises were performed in a manner of 2x25 repetition. EMG activity, lactatedehidrogenase, creatine kinase and myoglobin values were measured before and immediately after, at 24th, 48th, 72nd, 168th hours following exercise.Two way ANOVA with repeated measures on EMG values collected from M. Vastus Medialis and M. Rectus Femoris before and after one set maximum loading resistance exercise showed significant main effect for time (p<0,05), however there was no significant main effect for trial by time interactions and for trials. According to the two way ANOVA with repeated measures, which was conducted for the muscle damage exercise protocol, no significant difference was observed in the data, except the change in the EMG maximum value of M.Rectus Femoris (p<0,05).As a conclusion, changes were recorded over time regarding to EMG and muscle damage responses during the recovery period following intensive resistance exercises. However, no differences were observed among the types of contractions.