Whoever asked this question must have used it. This is the difference between dynamic and static. In order to keep healthy, regardless of the release and transmission of strength at the start, it is naturally balanced labor, with the center of gravity at the foot in the middle or slightly backward, so the waist naturally stretches or leans back slightly, striving for balance and comfort, giving priority to relaxing the spine and nourishing the limbs. Taking Dachengquan as an example, Mr. Yu Yongnian's piling method is basically the same. As for practicality, there must be opportunities. The transmission of the center of gravity is based on the practice of ontological struggle, and the application of the center of gravity always carries out the achievement method, so it is inevitable that the center of gravity will move forward and reach the tiptoe, which is very easy to use. The waist will naturally stretch back and forth, which will make the spine strongly stretched and pulled up. Take Dachengquan as an example, Mr. Yao Zongxun's early piling was like this. Bruce Lee didn't stand on the pile, but the method of advancing and retreating with fists and legs didn't conform to this principle, so the boxing book was the same, and the principle was better. Questions and answers touch the whole body. It takes more than a few words to make it clear, and with a little self-criticism, smart people will understand.