Do sit-ups in the primary stage, because the abdominal strength is weak, it is difficult to lift the upper body, so you need to hold down the glue, move your center of gravity down, increase the abdominal strength and lift the upper body. But after a period of exercise, you can do sit-ups without pressing your feet. The specific operation steps are as follows:

1, legs bent 90 degrees, heel on the ground.

2. Keep your spine straight and lie on the ground.

3. Touch your ears with both hands and don't drag your head to increase the stress on the cervical spine.

4. When the upper body runs up, make sure that the spine is straight and don't bend.

5. When the body rises to be perpendicular to the ground, run down slowly to complete an action cycle.