Its advantages are: first, saving energy; Second, reduce or eliminate the risk of cross-joint stretching ability; Third, it will not stimulate the traction reflex. Herbert Defrees wrote in his article "Spastic Theory of Abdominal Pain in Articulated Muscles": If you hit a muscle or tendon quickly, you will get much greater response than slow stretching. On the contrary, if you stretch slowly, you may not get any response at all. Two important factors in the application of static stretching method are how much force is used during stretching and how long the soft tissue should stay after stretching. The strength of tensile strength should be defined by the athlete's feeling of acid, swelling and pain. If the training intensity is lower than this, the athlete's body can't get the intensity stimulation it deserves, and the soft tissue can't be pulled to the possible length, and the training effect can't be achieved. If the training intensity is too high, it will damage the soft tissue, even if it is not obvious for a while, it will accumulate into trauma over time. Generally speaking, when the soft tissue is stretched to soreness and pain, the retention time is 8~ 10S. The number of repetitions was 8~ 10.