Final answer:
The class of skeletal muscle fibers found in large motor units is type IIb (fast-twitch glycolytic) fibers, which are ideal for short, anaerobic, and forceful activities but fatigue quickly.
Step-by-step explanation:
Types of Skeletal Muscle Fibers in Large Motor Units
The class of skeletal muscle fibers found in large motor units is type IIb (fast-twitch glycolytic) fibers. These fibers can contract quickly and with a greater force than oxidative muscles, which makes them suitable for short, anaerobic bursts of activity that require powerful movements. They possess large glycogen reserves, which they use to generate energy quickly through anaerobic glycolysis, but they fatigue more rapidly than the oxidative fibers. Unlike slow-twitch fibers, which are rich in mitochondria and myoglobin, fast-twitch glycolytic fibers are less dense in these components.