Sit-ups are an important part of physical exercise, and some people even misunderstand them as helping to reduce abdominal fat. Some studies have pointed out that if sit-ups are trained less than 150 times each time, the purpose of losing weight will not be achieved. Because sit-ups are very tired, but they don't consume a lot of calories. Even for sit-ups with a lot of exercise, the energy consumed comes from body fat, not just the abdomen. The advantage of doing sit-ups properly is that you can strengthen and strengthen your abdominal muscles. The strength of abdominal muscles has a good supporting effect on your back, allowing you to increase your physical strength in other aerobic sports and recreational activities. Therefore, even if you insist on doing sit-ups every day, you don't consume much abdominal fat, and you can't achieve the goal of reducing your stomach. On the contrary, it will develop your abdominal muscles and increase your muscles. Efficient aerobic exercise is the best exercise to lose weight. Research shows that aerobic exercise training for more than 20 minutes at a time can reduce the accumulated fat in the body and achieve the purpose of losing weight. The main function of sit-ups is to strengthen abdominal muscles. If done correctly, sit-ups can not only improve the elasticity of abdominal muscles, but also protect the back and improve the posture. On the other hand, if not done well, sit-ups are not only a waste of time, but even harmful. According to Stamford (1997), the correct way to do sit-ups is to lie on the floor mat, with your knees bent about 90 degrees and your feet flat on the ground. Don't fix your feet on the flat ground (for example, your partner presses your ankles with his hands), otherwise the flexors of thighs and buttocks will also join the work, thus reducing the workload of abdominal muscles. Furthermore, straight leg sit-ups will increase the burden on the back and easily cause damage to the back. Determine the position of your hands according to the strength of your abdominal muscles, because the closer your hands are to your head, the more difficult it will be to do sit-ups. Novices can put their hands on their sides, and when they get used to it or improve their physical fitness, they can cross their hands on their chests. Finally, try to cross your hands behind your head, but each hand should be placed on the shoulder on the other side of your body. Never cross your fingers behind your head, so as not to strain the neck muscles when exerting force, and this will also reduce the workload of abdominal muscles. Use a slower speed, just like slow-motion playback. When the abdominal muscles pull you up, you have to exhale, so as to ensure that all the muscles deeper in the abdomen participate in the work at the same time. After the body is off the ground 10 to 20 cm, tighten the abdominal muscles, pause for a while, and then slowly lower the body back to its original position. When your back touches the ground, you can start the next cycle. In the process of sit-ups, the abdominal muscles actually only participate in the work at the initial stage, and then the hip flexors will replace the task. Similarly, turn your body in the final stage of sit-ups (right elbow touches your left knee, left elbow touches your right knee, etc.). ) not only will it not help to strengthen the abdominal muscles, but it will even cause trauma to the lower back due to the compression caused by rotation. Beginners should avoid doing sit-ups too many times at a time. At first, they can try to do it five times, and then add it once in each exercise until it reaches about 15 times. At this time, they can try to do another group until they reach three groups.