Influence of muscle damage and inflammation on the repeated bout effect and skeletal muscle hypertrophy pathway

Abstract

The performance of an intense strength training bout may induce damage to the skeletal muscle structure resulting in an associated inflammatory response. However, muscle damage extent decreases in the following training sessions. This phenomenon is known as the repeated bout effect (RBE) and protects the muscle from future exercise induced damage. It seems that the magnitude of the muscle damage and inflammatory response affects the level of the protective adaptation (i.e. the bigger muscle damage/inflammatory response the bigger the RBE). In addition, the occurrence of muscle damage has been related to the activation of the hypertrophic process. Thus, the RBE may progressively decrease the hypertrophic response to the strength training stimuli. Assuming that the RBE is dependent on the level of inflammation, if the inflammatory reaction due to muscle damage is reduced, we can expect that the adaptations behind the RBE will be also reduced. Consequently, a decreased RBE will result in higher levels of exercise induced muscle damage which in turn may activate hypertrophy process. (AU)