It is emphasized that it must be "slow" because generally speaking, in the process of "armchair squat", on the one hand, for safety reasons, the function of armchair is to reduce part of the pressure on the legs and avoid physical problems; On the other hand, from the human body, when the thigh squats to a certain angle, the muscles are exerting force. Beyond this angle, it will automatically come down and get up, which will often empty the strength of many muscle groups in the thigh. If you squat slowly, you can effectively improve the strength of all links of leg muscles. When the thigh can gently rise and fall at any angle without the feeling of automatic up and down, it shows that every muscle group in the leg is working, and it also shows that exercise is effective.