What changes occur in the musculoskeletal system due to immobility?

• A. Loss of muscle mass, muscle weakness, and joint contractures
• B. Increased bone density
• C. Shorter healing time
• D. Increased flexibility

Answer: (A)

When movement stops, the body’s muscles and joints respond to disuse. Without regular loading and activity, muscles undergo disuse atrophy—protein breakdown exceeds synthesis—so muscle mass shrinks and strength declines. At the same time, the soft tissues around joints become less pliable and can shorten, leading to contractures that limit range of motion. These changes—loss of muscle mass, muscle weakness, and joint contractures—are the typical musculoskeletal effects of immobility.

Inactivity does not increase bone density; it tends to reduce it, increasing fracture risk over time. Healing tends to be slower, not shorter, because reduced circulation and mechanical stimulation slow tissue repair. Flexibility also tends to decrease due to stiffness, not increase.