What Are Fast- and Slow-Twitch Muscles?
Know any HIIT aces who struggle to run a mile? How about amarathoner who can’t nail a box jump? The difference might lie in the makeup of their skeletal muscles.
People have two general types of skeletal muscle fibers: slow-twitch (type I) and fast-twitch (type II). Slow-twitch muscles help enable long-endurance feats such as distance running,