Which fiber type would be more advantageous for marathon running?

• A. Fast-twitch fibers
• B. Slow-twitch fibers
• C. Intermediate fibers
• D. Hybrid fibers

Answer: (B)

Slow-twitch fibers are more advantageous for marathon running because they are specifically adapted for endurance activities. These fibers, also known as type I fibers, have a high density of mitochondria, rich blood supply, and a greater capacity for aerobic metabolism. This allows them to efficiently use oxygen to produce energy over extended periods, making them ideal for long-distance running where stamina is crucial.

In contrast, fast-twitch fibers are designed for short bursts of high-intensity activity and rely more on anaerobic metabolism, making them less suited for prolonged endurance events. Intermediate and hybrid fibers have characteristics of both slow-twitch and fast-twitch fibers, but they do not match the endurance capabilities of slow-twitch fibers. Therefore, for marathon runners who require sustained energy release over several hours, slow-twitch fibers are the preferred muscle fiber type.