萎缩

长期缺乏运动，他的腿部肌肉已经开始萎缩。

Chángqī quēfá yùndòng, tā de tuǐbù jīròu yǐjīng kāishǐ wěisuō.

Due to long-term lack of exercise, the muscles in his legs have begun to atrophy.