It is well documented that muscle soreness occurs when performing eccentric exercise, and muscle soreness is an indication of muscle damage. Muscle soreness after eccentric exercise develops in several hours and peaks at 1-3 days after exercise, then subsides gradually. Exercises are often performed using sore muscles. It has not been investigated that how the exercises with sore muscles influence the recovery from muscle damage. The purpose of this study was to test the hypothesis that performing repeated bouts of eccentric exercise when muscles were sore and not recovered from previous eccentric exercise would exacerbate muscle damage and retard recovery process. Eight male students (19.6±1.3 yrs) who had never involved in any resistance training program were used as subjects. One arm performed three sets of 10 eccentric actions of the elbow flexors (ECC) using a dumbbell that was set at 50% of the preexercise maximal isometric force level with the elbow joint angle at 90 degrees (1 bout condition). The other arm performed the same exercise three weeks later, and repeated the exercise in every other day for 3 times (ECC 1, ECC 2, ECC 3) (3 bouts condition).
　Changes in maximal isometric force (MIF), relaxed (RANG) and flexed elbow joint angle (FANG), circumferences of the upper arm (CIR), muscle soreness, and plasma creatine kinase activity (CK) were compared between the arms. These measures were assessed immediately before and after each ECC and for 5 days after exercise in the 1 bout condition and for 1 day after the 3 bouts condition. All measures changed significantly immediately after ECC in the 1 bout condition as well as ECC 1-3 (P<0.05). Changes in MIF, RANG, and CIR were significantly different bet-ween the conditions, but recovery process did not seem to be exacerbated in the 3 bouts condition. Muscle soreness did not develop after ECC 2 and ECC 3, and the soreness level even decreased significantly (P<0.05) immediately after ECC 2 and ECC 3. These results suggest that eccentric exercise performed with "sore muscle" did not produce further soreness and muscle damage nor exacerbated the repair process when the exercise was repeated every other day.

DESCENTE SPORTS SCIENCE Vol.17/THE DESCENTE AND ISHIMOTO MEMORIAL FOUNDATION FOR THE PROMOTION SPORTS SCIENCE