Johnston developed a strategy to increase training load on frontier fibers directly while keeping heart rate well below ...

Fast-twitch muscle fibers are larger and help your body move quickly and generate significant force. Sprinters tend to have an abundance of fast-twitch muscle fibers.

Lifting heavy weights builds fast-twitch muscle fibers, which power short bursts of energy and fatigue quickly, says N’namdi Nelson, an exercise physiologist at NYU Langone’s Sports ...

Fast-twitch fibers are geared toward powerful, explosive movements, whereas slow-twitch fibers support sustained, endurance exercises and joint stabilization.

Experts define power as the ability to apply force rapidly — using fast-twitch muscle fibers in short, explosive bursts. Strength allows you to lower into a chair, power gets you back up.