Understanding the societal and personal impact of immobilization or disuse syndrome is important in Japan with its large elderly population. The indication of disuse syndrome for rehabilitation was narrowed and the fee for disuse syndrome was set at a low level. Muscle strength decreases at a rate of 2.3 % per day in 40 % of the people. Also, the muscle fractional synthetic rate decreased with 10 days rest. Other functional or morphological changes also occur in the neuromuscular junction and the muscle internal structure. Additionally, we must consider the contribution of muscle to the limitation of joint angle after immobilization. Both elasticity and viscosity increase. Cardiac wall thickness and cardiorespiratory fitness decrease during immobilization. Gravitational dependent lung disease or deep vein thrombosis may occur. The brain is also affected by immobilization, leading to condition of learned non-use. The best solution for immobilization is to be active ; however, we must have a detailed knowledge of the pathophysiology of a patient's disease in order increase their activity level. In an acute hospital setting, prevention of immobilization is crucial. The system used in Japan, whereby therapists are assigned full-time in the ward was introduced in April 2014. Furthermore, even though 20.35% of maximal strength training is effective in atrophied muscles, it is ineffective in trained muscles. Another sticking point is that there is no evidence-based recommendation for range of motion exercise. However, rehabilitation intervention in respirator patients improves their ADL. Prophylaxis of deep vein thrombosis is also very important. And learned non-use of the brain may be diminished by the skillful application of vibrations that makes patients feel that their hand is moving even when it is not. Finally, the mechanism of hibernation may be the key to improving our rehabilitation against immobilization in the future.