Evidence of a contralateral repeated bout effect after maximal eccentric contractions.

The aim of this investigation was firstly, to examine whether a contralateral repeated bout effect is manifested after a single bout of maximal eccentric muscle actions and secondly, to compare the magnitude of any such protection to an ipsilateral control. Sixteen male subjects undertook 45 repetitions of maximal eccentric contractions of the elbow flexors. The ipsilateral group (IL, N=8) repeated the exercise using the same arm and the contralateral group (CL, N=8) repeated the exercise using the contralateral arm 14 days later. Serum creatine kinase (CK), muscle soreness, maximal voluntary contraction (MVC) and range of motion (ROM) were significantly attenuated in the repeated bout for IL. CL also showed a significant reduction in the repeated bout for CK, muscle soreness and MVC. Despite the significant attenuation of dependent variables in both groups the magnitude of change was less in CL compared to IL for CK, soreness, MVC and ROM. The findings demonstrate a repeated bout effect in the contralateral limb after a single bout of maximal eccentric exercise; however, the magnitude of protection in the contralateral limb is less than that manifested in the ipsilateral limb. The apparent contralateral repeated bout effect observed in this investigation is thought to be predominantly mediated by neural mechanisms, although further research is required to elucidate this possibility.