Slow twitch fibers are characterized by which of the following traits?

Slow twitch muscle fibers, also known as Type I fibers, are characterized by high fatigue resistance. They are optimized for endurance activities and are able to sustain prolonged contractions, making them ideal for activities such as long-distance running or cycling. The higher content of myoglobin and mitochondria in these fibers increases their oxygen delivery and supports aerobic metabolism, allowing them to produce energy over an extended period without fatiguing easily.

In contrast, slow twitch fibers do not contract quickly, and rather, they excel at maintaining a steady state of activity over longer durations. Their energy duration is also longer compared to fast twitch fibers, which tend to provide short bursts of energy for quick and intense activities but fatigue rapidly. Therefore, high fatigue resistance is the defining characteristic of slow twitch fibers, situating them as essential for endurance-based performance.