What is muscle atrophy?

• A. Increase in muscle mass due to lack of use or immobility.
• B. Decrease in muscle mass due to lack of use or immobility.
• C. Inflammation of muscle tissue.
• D. Muscle hypertrophy with aging.

Answer: (B)

Muscle atrophy is the decrease in muscle mass that happens when muscles aren’t used enough, such as with immobility or extended bed rest. When the body doesn’t require strong muscle contractions, it conserves energy by reducing the size of muscle fibers, leading to smaller, weaker muscles. This is different from inflammation of muscle tissue, which would involve pain and swelling, and from hypertrophy, which is an increase in muscle size due to training. Aging can contribute to some muscle loss, but atrophy specifically refers to loss from disuse rather than aging alone. In practice, preventing atrophy involves encouraging movement as soon as it’s safe, providing range-of-motion exercises, and ensuring adequate nutrition to support muscle maintenance.