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Multiple Choice
The type of muscle fiber that is most resistant to fatigue is the ________ fiber.
A
fast oxidative-glycolytic (Type IIa)
B
intermediate (Type III)
C
fast glycolytic (Type IIb)
D
slow oxidative (Type I)
Verified step by step guidance
1
Understand the different types of muscle fibers: Muscle fibers are categorized based on their contraction speed and metabolic properties. The main types are slow oxidative (Type I), fast oxidative-glycolytic (Type IIa), and fast glycolytic (Type IIb).
Learn the characteristics of slow oxidative (Type I) fibers: These fibers are highly resistant to fatigue due to their reliance on aerobic metabolism, which provides a steady supply of energy. They have a high density of mitochondria, capillaries, and myoglobin, making them efficient for prolonged activities like endurance running.
Compare with fast oxidative-glycolytic (Type IIa) fibers: These fibers are intermediate in terms of fatigue resistance. They use both aerobic and anaerobic metabolism, making them less resistant to fatigue than Type I fibers but more resistant than Type IIb fibers.
Compare with fast glycolytic (Type IIb) fibers: These fibers rely primarily on anaerobic metabolism, which provides quick bursts of energy but leads to rapid fatigue. They are suited for short, high-intensity activities like sprinting.
Conclude that slow oxidative (Type I) fibers are the most resistant to fatigue due to their reliance on aerobic metabolism and structural adaptations for sustained energy production.