How can astronauts maintain good muscle condition?

In zero gravity condition, astronauts uses different devices or self exercise to trained their muscles which are getting affected by zero G. such as legs, simply they could hold something against them forcing anywhere and trained thier muscle to prevent it from getting weak. Moreover, they sometime PLAY as a team inside the spacecraft, its purpose is to relax and prevent muscle fatigue as well as clear up their minds from unusual living condition.

在太空中之無重狀態，任何物件都是很輕的，所以肌肉是無須發出強大力量。在這情況下，身體為了適應當時之狀況，會大幅減少供養肌肉細胞，同時受損之肌肉細胞都不會替換，這過程叫肌肉退化，通常在一、兩星期間已相當明顯。太空人為了在降落回地球時有足夠肌肉力量去應付降落工作，所以在太空時必須每天用幾小時去保持一定之肌肉力量。現時通常利用像根模擬重力訓練手部肌肉、彈弓訓練手指肌肉及健身單車訓練腳部肌肉。