Welcome to JING TV! There is balance in the universe, and so there should be balance in your Taiji (Tai Chi) and in your Wushu (Kung Fu). If a limb is going up, there must be another going down. If some part of your posture twists left, then another must pull right. If you have a strong forward motion, then there should be a equal backwards action to balance it and keep you from falling forward on your face. It is all about the Yin Yang Principle!