Type 2b muscle fibers are fast-twitch fibers associated with which of the following?

• A. Slow-twitch fibers for endurance
• B. Intermediate fibers for mid-distance
• C. Fast-twitch fibers for sprinting and maximal strength tasks
• D. Fast-twitch fibers for endurance at long durations

Answer: (C)

Type 2b fibers are fast-twitch fibers that contract quickly and generate a lot of force, mainly using anaerobic glycolysis. They have high glycolytic capacity, large motor units, and fatigue rapidly, which makes them ideal for very short, explosive efforts. This is why they are linked to sprinting and maximal-strength tasks—activities that require a quick, powerful burst of work. They aren’t meant for endurance or long-duration efforts, which rely on slow-twitch fibers (for fatigue resistance) or, to some extent, fast-twitch IIa fibers that blend speed with oxidative capacity. So the best match is fast-twitch fibers for sprinting and maximal strength tasks.