What is a common characteristic of fast-twitch muscle fibers?

Fast-twitch muscle fibers, also known as Type II fibers, are characterized by their low resistance to fatigue. These fibers are designed for quick bursts of activity and are primarily used in high-intensity, short-duration exercises, such as sprinting or weightlifting. While they can generate a lot of force rapidly, they do so at the cost of endurance, meaning they get fatigued more quickly compared to slow-twitch fibers.

The nature of these fibers allows them to produce explosive power but doesn't lend itself to prolonged activity. During exertion, they rely on anaerobic processes for energy, which leads to a quicker accumulation of lactic acid and a rapid onset of fatigue. This characteristic distinguishes fast-twitch fibers from slow-twitch fibers, which have greater endurance and can sustain activity over a longer period without fatigue.

Understanding this distinction is crucial for fitness professionals when designing training programs targeting specific athletic goals, whether it be strength, speed, or endurance.