Which condition occurs when muscle decreases in size and becomes weak?

Atrophy is the correct term for the condition in which muscle decreases in size and strength. This process typically occurs when a muscle is not regularly exercised or when there is a lack of physical activity, which leads to a reduction in muscle fibers and overall muscle mass. Atrophy can also result from certain medical conditions, aging, or prolonged immobility.

In contrast, hypertrophy refers to the increase in muscle size due to strength training or increased workload, thus enhancing muscle fibers. Cramps are sudden and involuntary muscle contractions that can cause pain but do not signify a decrease in size or strength. Contracture refers to the shortening or tightening of muscles, tendons, or other tissues that inhibit normal movement and often occurs due to disuse or neurological conditions, but it does not specifically denote a decrease in muscle size. Therefore, atrophy is the only condition that directly describes the shrinking and weakening of muscle.