他们感受不到脚底的存在，他们不知道自己的手指和手掌何时有力地张开平放在地面上，他们也不能够一次将手臂伸直或展开四头肌维持几秒钟。

They don't know when their fingers are spread wide and their palms are flat against the ground. Nor can they hold their arms straight or their quadriceps engaged for more than a few seconds at a time.

youdao