Influence of previous concentric exercise on eccentric exercise-induced muscle damage.

This study investigated whether a fatiguing concentric exercise performed immediately before eccentric exercise would exacerbate eccentric exercise-induced muscle damage. One arm of nine female subjects (mean +/- s: 23.3 +/- 6.7 years) performed 12 maximal eccentric actions of the elbow flexors (ECC), and the other arm performed 100 repetitions of isokinetic concentric actions of the elbow flexors followed by the same eccentric exercise (CON-ECC). The two exercise regimens (ECC and CON-ECC) were separated by 2 weeks and presented in a counterbalanced order. Changes in muscle soreness level, maximal isometric force generation, relaxed and flexed elbow joint angle, upper arm circumference and plasma creatine kinase activity were compared between the ECC and CON-ECC conditions. All measures changed significantly after both ECC and CON-ECC; however, there were significant differences in the changes between the conditions. A lower level of soreness, a faster recovery of maximal isometric force generation, a smaller decrease in relaxed elbow joint angle and a smaller increase in upper arm circumference and creatine kinase activity were evident after the CON-ECC condition compared to the ECC condition. Thus, it would seem that muscle damage was attenuated by performance of previous concentric exercise. An additional experiment using a different group of subjects (n = 5) showed that warm-up exercise before the eccentric exercise also attenuated eccentric exercise-induced muscle damage.