used to describe a type of muscle that is used for sudden, fast movements such as sprinting (= running fast over short distances)

Fast-twitch fibers use no oxygen and provide quick bursts of energy. Slow-twitch fibers draw oxygen from blood and provide steady, consistent movement. 快速收缩纤维不需要氧气，提供快速爆发的能量。慢收缩纤维从血液中吸收氧气，实现稳定、持续的运动。