Effects of exhaustive dumbbell exercise after isokinetic eccentric damage: recovery of static and dynamic muscle performance.

This study examined the recovery of static and dynamic muscle performance after eccentric damage with and without repeated exercise, using different exercise modes between the initial and subsequent exercise bouts. Twelve nonweight-trained adults performed both control and repeated exercise conditions. Soreness, limb circumference, static joint angles, creatine kinase (CK), isometric strength, and dynamic muscle performance involving a stretch-shortening cycle (SSC) were monitored for 7 days to evaluate the recovery. After baseline measures, subjects performed 30 maximal isokinetic eccentric contractions (90 degrees/second) of the elbow flexors in each experiment. For the control condition, no treatment was applied. For the repeated exercise condition, 5 sets of arm curls using dumbbells (70% isometric maximal voluntary contraction of each testing day) were performed until failure on days 1, 2, 3, and 5 of recovery. Significant condition vs. time interactions existed in circumference (p = 0.012), static relaxed angle (p = 0.013), isometric strength (p = 0.039), and dynamic extension angle (p = 0.039), suggesting a slightly delayed onset of recovery with the repeated exercise. SSC performance changed more in parallel with soreness after eccentric exercise than did the other measures. It was concluded that the repeated bout effect was present, although slightly reduced, when subsequent exercise performed before recovery was intense and differed in mode from the initial eccentric exercise. Practical applications of this research are that resistance training may be continued after eccentric damage; however, a minor delay in the onset of recovery may occur depending on training modes. Muscle soreness is a good indicator of performance decrement during dynamic movements following eccentric damage.