Which muscle fiber type is more resistant to fatigue and suited for aerobic activity?

The choice of slow twitch/type 1 muscle fibers is accurate due to their design, which maximizes endurance and resistance to fatigue. These fibers are rich in mitochondria, myoglobin, and capillaries, providing an efficient supply of oxygen for aerobic energy production. They primarily utilize aerobic metabolism, making them ideal for sustained, long-duration activities such as distance running and cycling, where endurance is crucial.

These characteristics enable slow twitch fibers to contract repeatedly over prolonged periods without succumbing to fatigue, setting them apart from other muscle fiber types. Fast twitch/type 2b fibers, for example, are geared more towards short bursts of power and speed, but they fatigue quickly. Fast twitch/type 2a fibers do possess some aerobic capacity, yet they are still less resistant to fatigue than type 1 fibers. The intermediate twitch/type 1.5 does not have a widely accepted classification or specific attributes outlined in the traditional understanding of muscle fiber types, making it less relevant in the context of endurance activities.

In summary, slow twitch/type 1 fibers are specifically adapted for activities that require endurance and sustained performance, making them the correct answer.