Question

Local muscles typically consist of which type of muscle fibers?

A) Type I (slow-twitch) fibers
B) Type IIa (fast-twitch oxidative) fibers
C) Type IIb (fast-twitch glycolytic) fibers
D) Type III (intermediate) fibers

Answer 1

Local muscles consist mainly of Type I (slow-twitch) fibers which are adapted for endurance activities due to their ability to generate energy through aerobic metabolism.

Step-by-step explanation:

Local muscles are composed predominantly of Type I (slow-twitch) fibers. These muscle fibers are characterized by their high density of capillaries, plentiful mitochondria, and rich content of myoglobin, giving them a red appearance.

Slow-twitch fibers are mainly responsible for endurance activities such as long-distance running because they use aerobic metabolism to produce ATP, allowing the muscle to sustain activity over long periods without fatigue.