ABSTRACT

　It is well known that exercise training induces mitochondrial biogenesis in skeletal muscle. More recent studies have demonstrated that exercise also alters mitochondrial quality through the processes of fission and fusion. In this study, we investigated the effect of electrical stimulation-induced resistance training, which induces muscle hypertrophy, on the expression of proteins related to mitochondrial dynamics in rat skeletal muscle. We found that 4 weeks of resistance training increased protein levels of mitofusin 2 (Mfn2) and optic atrophy 1(Opa1), whereas protein levels of fission protein 1 (Fis1) and dynamin related protein 1 (Drp) were not altered. These results indicate that resistance training induces mitochondrial fusion, which may lead to an expanded mitochondrial reticular network along with muscle hypertrophy. It has been generally assumed that resistance training has little effect on skeletal muscle mitochondria. However, our results suggest that resistance exercise training may increase mitochondrial function without changing mitochondrial content in skeletal muscle.

DESCENTE SPORTS SCIENCE Vol.38/THE DESCENTE AND ISHIMOTO MEMORIAL FOUNDATION FOR THE PROMOTION SPORTS SCIENCE