What characteristic does Type 2 muscle fibers (fast twitch) have concerning their energy usage?

Type 2 muscle fibers, commonly known as fast-twitch fibers, are characterized by their ability to generate quick and powerful bursts of energy but with a drawback: they fatigue quickly. This characteristic is due to their reliance on anaerobic metabolism for energy production, which happens without oxygen.

Fast-twitch fibers are designed for short-duration, high-intensity activities, such as sprinting or weightlifting, where rapid energy is required. The rapid conversion of energy in these fibers leads to the accumulation of lactic acid, which contributes to faster fatigue compared to slow-twitch fibers that are more endurance-oriented and utilize aerobic respiration.

While the other options touch on aspects of muscle fibers, they do not correctly represent the primary characteristic of Type 2 fibers. For instance, fast-twitch muscle fibers do not primarily utilize aerobic respiration, as that is more characteristic of slow-twitch fibers. Additionally, they do not predominantly burn fat for energy; instead, they rely on carbohydrate sources for quick energy bursts. Finally, fast-twitch fibers do not typically require a high oxygen supply, as their energy production occurs mainly through anaerobic processes.