Sit-ups are a form of exercise. Lie on your back, put your legs together, raise your hand, contract your abdominal muscles, swing your arms forward, and quickly become a sitting position. Keep your upper body bent forward, touch your feet with your hands and bow your head. Then return to the sitting position. So continuous. Sit-ups are an important part of physical exercise, and their main function 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. Sit-ups are an effective way to exercise abdominal muscles. In addition, they are simple and unaffected by the site environment. They are quite suitable for the general public, especially middle-aged men and women who are looking forward to eliminating abdominal fat and avoiding low back pain.