Influence of resistance exercise intensity and metabolic stress on anabolic signaling and expression of myogenic genes in skeletal muscle

: We investigated the effect of resistance exercise intensity and exercise‐induced metabolic stress on the activation of anabolic signaling and expression of myogenic genes in skeletal muscle. Methods : Ten strength‐trained athletes performed high‐intensity [HI, 74% of 1‐repetition maximum (RM)], middle‐intensity (MI, 54% 1RM), or middle‐intensity (54% 1RM) no‐relaxation exercise (MIR). Kinase phosphorylation level and myogenic gene expression in muscle samples were evaluated before, 45 min, 5 h, and 20 h after exercise. Results : The lactate concentration in MI was approximately 2‐fold lower than in the 2 other sessions, and was highest in MIR. The phosphorylation level of extracellular kinase 1/2 Thr202/Tyr204 after exercise was related to metabolic stress. Metabolic stress induced a decrease in myostatin mRNA expression, whereas mechano‐growth factor mRNA level depended on exercise intensity. Conclusions : This study demonstrates that both intensity and exercise‐induced metabolic stress can be manipulated to affect muscle anabolic signaling. Muscle Nerve 51: 434–442, 2015