This study compared two training regimens in which knee extensor exercises were performed at different range of motion.
Methods: Sixteen males performed bouts of 90 maximal isokinetic eccentric contractions over 6 consecutive days (B1-B6) at either small (n=8) or large (n=8) range of motion. Average of peak torque (Mp) of each of the 90 contraction trials were calculated, plasma creatine kinase (CK) and lactate dehydrogenase (LDH) activities were measured before, 24 h, 48 h and 6 d after B1. Muscle soreness was evaluated every day during the experiment.
Results: At B3 Mp reduced more in group L than in group S. From B1 to B6 group S increased Mp, while in group L Mp did not return to the baseline level. In both groups CK activity elevated 24 h following B1. CK activity was significantly higher in group L 6d after B1. In group L muscle soreness was higher at 48 h, 72 h, 4 d and 5 d after B1.
Conclusion: High-intensity, consecutive eccentric knee extensor exercise training at large range of motion may induce greater development of muscle damage and force deficit, than training at small range of motion. Training at small range of motion may induce early adaptation in voluntary torque production.