Fast-twitch fibers
A) are also called white muscle.
B) fatigue rapidly.
C) have fewer mitochondria per cell compared to slow-twitch fibers.
D) are also called glycolytic muscle.
E) All of the above

Question

Quizplus · Accepted Answer

All of the above statements are true. Fast-twitch fibers are also called white muscle because they have fewer blood vessels and less myoglobin than slow-twitch fibers, which gives them a lighter color. They fatigue rapidly because they rely heavily on anaerobic metabolism to generate energy, which can create lactic acid build-up and reduce their ability to contract. They also have fewer mitochondria per cell compared to slow-twitch fibers, which rely on aerobic metabolism to sustain contractions. Therefore, fast-twitch fibers are also called glycolytic muscle because they rely primarily on glycolysis to produce ATP.

Fast-Twitch Fibers