Skeletal muscle constituting about 40% of body weight, plays a crucial role in exercise performance and whole body metabolism. Skeletal muscle tissue is composed of bundles of skeletal muscle fibers that are broadly classified as slow-twitch (type I) and fast-twitch (type II) fibers. Type I fibers are characterized by high contraction endurance and glucose uptake ability compared to type II fibers. Type I fibers undergo relatively less atrophy during age-related muscle atrophy in contrast to type II fibers. indicating that type I fibers exhibit resistance to age-related muscle atrophy. We speculate type I fiber specific molecules play a crucial role in preserving these fibers during atrophy.
Hu et al. (Thu,) studied this question.