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Muscle Composition

Meaning

Muscle composition describes the precise molecular and cellular makeup of skeletal muscle tissue, including the ratio of muscle fibers (Type I, Type II), intramuscular fat content, and the density of mitochondria and capillary networks. This internal structure is a direct reflection of both genetic predisposition and chronic hormonal signaling, with factors like thyroid hormone and growth hormone influencing fiber type distribution and metabolic capacity. Evaluating muscle composition, often through advanced imaging or biopsy, provides crucial clinical insights into an individual’s metabolic health, functional reserve, and susceptibility to sarcopenia. Optimizing this composition is a core objective of longevity and performance-based hormonal health interventions.