The correct way to do sit-ups:
1, bend your knees, lie on the ground, slightly separate your left and right feet, stride with shoulder width, keep your hips, waist, back and shoulder blades completely on the ground, bend your elbows, put your hands under your head, press your elbows down to the ground as far as possible, and fully open your chest.
2. In this lying posture, the head is slightly raised, the parts above the back leave the ground, stretching and progressing to the muscles between the shoulder blades, and at the same time tightening the chin downwards, looking at the abdomen, keeping this off-the-ground posture for 4 seconds, then lying down again and repeating it twice.
3. Keep the position above the back off the ground, and then release the hand resting on the back of the head. The right arm is straight obliquely upward, with an included angle of about 45 degrees with the ground, and the left arm is put down and straight with the left side. Be careful not to touch the ground and keep it parallel to the ground.
Keep your head and shoulders off the ground. At this time, the left arm swings upward, keeping an included angle of 45 degrees with the ground, while the right arm swings downward, parallel to the ground, and swings back and forth alternately for four times.
5. Both arms are extended upward at the same time, and the included angle with the ground is expanded to 60 degrees. Straighten your legs and lift them straight up. Keep your feet facing the ceiling so that your legs are perpendicular to the ground. Keep your back and head off the ground and keep your posture for 4 seconds.
6. Lift your legs and bend your knees, and lower your calves so that the thighs and calves form a 90-degree right angle. Don't change your posture, retract your arms, bend your elbows on the back of your head and open your chest. Remember to close your chin and keep your eyes on your abdomen.
7. Bend your knees and lift your legs. At this time, the calves cross each other. First, the right calf is on it and held for 4 seconds. During this period, the upper body should be balanced, and the posture of the back and head off the ground should remain unchanged. Be careful not to cross your arms and open your chest.