Question

Slow twitch fibers have

• A. Small diameter
• B. Burst of power
• C. More myoglobin
• D. Fewer mitochondria

Answer 1

The correct option is B

Burst of power

Red fibers are smaller in diameter; white fibers are larger in diameter. Red fibers have more mitochondria than white fibers. Red fibers make up slow-twitch muscle; white fibers make up fast-twitch muscle. Red fibers are more resistant to fatigue than are white fibers. Red fibers have more myoglobin (oxygen binding pigment) and also a large concentration of mitochondria than white fibers. White fibers store glycogen and use anaerobic metabolism.

Red fiber and slow twitch muscle is for endurance.

White fiber and fast twitch muscle is for a burst of power.