What term describes the decrease in muscle strength due to lack of use?

The term that describes the decrease in muscle strength due to lack of use is muscle atrophy. Atrophy occurs when muscles are not engaged in regular use, leading to a reduction in muscle fibers and overall size and strength. This can happen due to various factors, such as prolonged inactivity, immobilization after an injury, or certain medical conditions that limit movement. As a result, the muscle weakens over time because it's not being challenged or exercised, causing it to lose mass and function.

In contrast, muscle hypertrophy refers to the increase in muscle size and strength resulting from exercise and resistance training. Muscle fatigue describes a temporary decrease in muscle performance due to overuse or exertion during physical activity. Muscle rigidity is associated with a state of stiffness in muscles, often seen in certain neurological conditions, but does not directly pertain to the loss of strength due to inactivity. Understanding these distinctions helps clarify the implications of muscle use and disuse in therapeutic and clinical settings.