1. Lie flat on the ground.

Put your hands behind your back.

3. Straighten your legs, slowly lift your feet together, and stay away from the ground 15-20cm for a few seconds.

4. Straighten your legs, slowly lift your feet together, and stay a few seconds away from the ground 15-20cm.

5. repeat the above actions, so that one lift and one release is a round trip.

Tip: This set of movements can be done with both legs together or separately.