如果你觉得走路都非常费劲，那你必须在这一阶段保持一段时间，直到感觉自己可以进行更强一点的训练。

If you feel that walking is already pretty strenuous for you then you should stay at this stage for some time until you feel that you can push yourself a little bit further.

youdao

如果你觉得走路都非常费劲，那你必须在这一阶段保持一段时间，直到感觉自己可以进行更强一点的训练。

If you feel that walking is already pretty strenuous for you then you should stay at this stage for some time until you feel that you can push yourself a little bit further.

youdao