Muscle atrophy is the gradual loss of muscle mass and strength, often resulting from inactivity, aging, or medical conditions. When muscles are not used regularly, they can shrink and weaken, leading to decreased physical performance and mobility. Several factors can contribute to muscle atrophy, including prolonged bed rest, certain diseases like muscular dystrophy, and malnutrition. Regular exercise, particularly strength training, can help prevent or reverse muscle atrophy by stimulating muscle growth and maintaining overall health.