1、前腿膝盖不要过于向前弯屈，当你发现膝头前倾的程度已经超过了脚尖时，就要注意将它缩回来一点。

　　The entire process to keep the upper body upright, legs and body not as backward tilt forward, otherwise unable to fully exercise the thigh, but also easy to injury to the muscles of the back.

　　2、整个过程中要保持上半身的挺直，身体不要随着腿部后滑而向前倾斜，不然既无法让大腿得到充分的锻炼，还容易伤到背部肌肉。

　　Do not backward leg in action off the ground, and do not slide too biased towards the outer side of the body.

　　3、腿部在做后滑动作时不要离开地面，也不要滑地过于偏向身体外侧。