Do it five times a minute at first, and then slowly increase it until it is about 30 times a minute. Pay attention to the waist, not the legs or arms, to avoid doing a lot of sit-ups at the beginning.

Thin waist action

Upper abdominal training-stretching back and touching feet

Lie flat, straighten your legs, lift almost perpendicular to the ground, put your arms back on your head, keep your legs straight as far as possible, lift your upper body completely with the strength of your abdomen, and keep touching your toes with your hands until you repeat this action 15 times.

Lateral abdominal training-leaning back and touching the knees

Lie flat, put your hands under your head, lift your legs perpendicular to the ground, bend your knees, pull your upper body backwards with your chin, touch your right knee with your right elbow, and then touch your left knee with your left elbow, 15 times on each side.

Lower abdominal training-supine leg lift

Lie flat, put your hands under your head, lift your legs to be perpendicular to the ground, then put them down without touching the ground, and complete them continuously 15 times.