What is the structural characteristic or shape of slow-twitch muscle fibers___________________?
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Answer: C. Red muscle
Explanation
Slow-twitch muscle fibers contain high concentrations of myoglobin, giving them a red appearance. The abundance of myoglobin and mitochondria enables these fibers to utilize oxygen efficiently. This high myoglobin content directly earns them the descriptive classification of red muscle. Muscle fibers are generally categorized into slow-twitch oxidative and fast-twitch glycolytic types. Slow-twitch fibers rely on aerobic respiration to produce adenosine triphosphate for sustained contraction. Their cellular structure provides remarkable resistance against fatigue during long-duration endurance activities.
Marathon runners possess a high percentage of these red slow-twitch fibers in their leg muscles. Understanding muscle fiber composition helps coaches design effective endurance training programs for athletes. These fibers are specialized for maintaining posture and performing prolonged sub-maximal physical efforts. White muscle fiber typically refers to fast-twitch fibers that rely on anaerobic energy pathways. Only A is incorrect because white muscle fibers do not describe slow-twitch characteristics. All above is incorrect since white muscle fibers do not share the red color classification.
- Subject
- Physical Education
- Category
- Physical Education
- Topic
- —
- Difficulty
- medium
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