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Muscle Fiber Types

Meaning

The established classification system for skeletal muscle cells, or myocytes, based on their distinct contractile, metabolic, and fatigue resistance properties. The primary classifications include Type I (slow-twitch, highly oxidative, fatigue-resistant) and Type II (fast-twitch, glycolytic, powerful), with Type II being further subdivided into Type IIa and IIx. The relative distribution and characteristics of these fibers determine an individual’s inherent capacity for endurance versus strength and power performance.