Maybe the exercise method of the subject is wrong. Subjects can try to support their heads with one hand and the bed with the other, and start doing side leg lifts. Toe down, heel up, slowly lift, then slowly put down, and the other leg is bent towards the flat plate. You can choose to speed up or slow down according to your own situation, but don't lift your legs violently. This side leg lift is done in four groups, five in each group. The last leg should be lifted, then stopped for a while, and then the other leg should be changed, which is also done by four groups. It is also possible to have a beautiful posture every day. It will be better to cooperate with this exercise!