fast-twitch vs. slow-twitch

fast-twitch vs. slow-twitch: What's the difference?

Fast-twitch and slow-twitch are types of muscle fibers discussed frequently in athletic contexts. Slow-twitch muscle fibers contract slowly and are specialized for endurance, while fast-twitch muscle fibers contract quickly and are specialized for power (e.g., sprinting). All muscles have a combination of the two types, but proportions can be different based on the muscle’s functions as well as a person’s training and genetics.