The progressive loss of skeletal muscle mass and strength that occurs with age is known as sarcopenia. Skeletal muscle is primarily composed of two types of muscle fibers, slow-twitch and fast-twitch fibers, based on their contractile properties. With aging, selective atrophy is observed in fast-twitch fibers. Resistance training improves skeletal muscle mass and strength. Resistance-training-induced muscle hypertrophy occurs in fast-twitch fibers rather than in slow- twitch fibers. Musashi RNA-binding protein 2 (MSI2) has been reported as a positive regulator of skeletal muscle mass and fiber types, and MSI2 deficiency leads to muscle atrophy and reduction of fast-twitch fibers, specifically type IIa muscle fibers. However, the effects of resistance training on MSI2 in skeletal muscle are unclear.
Hung et al. (Thu,) studied this question.