Final answer:
Atrophy is a decrease in muscle size due to cessation of use or exercise, often leading to weakness in the limbs. It can result from injury, disease such as cancer or AIDS, age, or prolonged inactivity. Exercises prescribed by physiotherapists can help maintain muscle strength and function.
Step-by-step explanation:
The cessation of use, practice, or exercise that leads to the loss of strength in the limbs is called atrophy. Atrophy is the decrease in the size of a muscle or other tissue due to non-use, disease, injury, or aging. Conditions such as cancer, AIDS, and age-related declines can lead to muscle atrophy, known as cachexia in severe cases or sarcopenia in the case of age-related loss. It can also occur due to disuse after situations like breaking a limb or undergoing surgery. Physiotherapists often assist patients in combating atrophy by prescribing exercises to stimulate affected muscles, helping to restore function and mitigate long-term muscle weakness.
Furthermore, prolonged periods of physical inactivity, such as bed rest or space travel, can contribute to muscle atrophy in humans, similar to what hibernating animals experience. Regular exercise contributes to the maintenance of muscle mass and strength and can delay or reduce the effects of atrophy by adding structural proteins, increasing cellular mitochondria, capillary density, and connective tissue mass. Physical activity is thus key in mitigating the impact of both disuse and age-related muscle atrophy.