Patrick Ryan, M.S.Physical inactivity, whether due to sedentary lifestyle or bedrest while recovering from injury or illness, is a significant detriment to overall health. In the short term, reducing activity results in muscle atrophy: the loss of both muscle size and strength. This problem not only applies to athletes who may be forced to reduce activity due to an orthopedic injury, or adults living a sedentary lifestyle, but is also a huge concern in regards to manned spaceflight.In low Earth ...