Muscles atrophy (get smaller) following broken bones, surgery, or serious illness. British researchers summarized the way in which muscles react to disuse and rehabilitation. Following injury or illness, muscles are resistant to normally anabolic stimuli such as amino acids and anabolic hormones. However, during rehabilitation, the body suppresses myostatin, which normally retards growth, and stimulates biochemical pathways that promote muscle protein synthesis and growth.
Rehabilitation exercises cause mild inflammation, which triggers the growth of satellite cells and muscle cross-sectional areas. Nonsteroidal anti-inflammatory drugs, such as ibuprofen and naproxen, interfere with satellite cell formation during rehabilitation, which slows down muscle rehabilitation. Intensely training athletes should minimize the use of these drugs when recovering from an injury. (Journal of Applied Physiology, 110: 555-560, 2011)