Muscle Atrophy
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The wasting away or shrinkage of muscle tissue from lack of use or immobilization.
Detail
Muscle atrophy refers to the wasting away or decrease in the size of muscle tissue from lack of use or through immobilization. It is the counterpart to hypertrophy: where training enlarges fibers, disuse and immobilization shrink them. A related point from the source's weight-control discussion is that muscles that are not used will simply experience atrophy (get smaller) — and fat tissue cannot turn into muscle, nor muscle into fat; unused muscle may merely be replaced by fat if a person consumes more calories than expended.
Key facts
- Atrophy = wasting away / decrease in size of muscle tissue.
- Caused by lack of use or immobilization.
- Opposite of hypertrophy.
- Unused muscle simply gets smaller (and may be replaced by fat if calories exceed expenditure).
Connections
- Muscle Hypertrophy — the opposite adaptation (growth).
- Muscle Tone — firmness lost with disuse.
- Recovery and Rebuilding Physiology — over-rest/lay-off leads to loss of contractile force.
- Principle of Disuse (Reversibility / "Use It or Lose It") — "use it or lose it" training principle.
Sources
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