Protective effect by maximal isometric contractions against maximal eccentric exercise-induced muscle damage of the knee extensors.

This study investigated whether maximal voluntary isometric contractions (MVIC) performed before maximal eccentric contractions (MaxEC) would attenuate muscle damage of the knee extensors. Untrained men were placed to an experimental group that performed 6 sets of 10 MVIC at 90° knee flexion 2 weeks before 6 sets of 10 MaxEC or a control group that performed MaxEC only (n = 13/group). Changes in muscle damage markers were assessed before to 5 days after each exercise. Small but significant changes in maximal voluntary concentric contraction torque, range of motion (ROM) and plasma creatine kinase (CK) activity were evident at immediately to 2 days post-MVIC (p < 0.05), but other variables (e.g. thigh girth, myoglobin concentration, B-mode echo intensity) did not change significantly. Changes in all variables after MaxEC were smaller (p < 0.05) by 45% (soreness)-67% (CK) for the experimental than the control group. These results suggest that MVIC conferred potent protective effect against MaxEC-induced muscle damage.