2. sit in a v shape. The whole person lies flat on the ground with his legs straight. Put your hands flat on the ground behind your body, keep your back straight and lift your legs straight off the ground. Then tighten your abdomen and pull your feet in the direction of your hips. Then go back to the first step. Back and forth. (This kind of action must keep the back straight, otherwise it won't take long for the back to be sour, so the strength will not be concentrated on the abdomen, and find the right point of force. ) 20 times in each group, 3 groups each time.
3. Sit-ups. Lie down with your back on the ground, your knees bent and your whole foot on the ground. Lift the head and shoulders off the ground for 20 ~ 30cm and keep the lower back in contact with the ground. Pay attention to exhaling when lifting. Then put down your body, don't completely touch the ground with your head and shoulders, and remember to keep your abdomen tense at all times. Sit-ups can be used as initial training, and each group 15 ~ 30, complete 3 groups at a time. Stick to it every day.
4. Flat bracket. Toes and forearms touch the ground to support the body, feet are hip-width, shoulders and elbows are at 90 degrees, trunk is straight, head and shoulders, crotch and ankles are kept at the same level as far as possible, abdominal muscles exert force, spine is extended, eyes are on the ground, uniform breathing is maintained, and this action is maintained as long as possible. Some people can't stick to this action for a minute. According to their physical fitness, they can persist for 30 seconds for the first time and add 5 seconds or 10 seconds for the second time. Add them up in turn, but pay attention to finding the right force point, otherwise it will have no effect.