Abstract
The responses of neuromuscular system to exposure to microgravity environment were studied in both human and rats. Both acute and chronic unloading inhibited the electromyogram activities of antigravity muscles. These phenomena were associated with an inhibition of afferent input. Detrimental effects on the neuromuscular coordination and/or work performance were also noted in response to chronic gravitational unloading. It is suggested that these results are related to the altered mobilization of motor units rather than the decreased tension development due to muscle atrophy.
