Abdominal muscles surround the periphery of internal organs, fixing the position of internal organs and preventing them from shifting at will. If the abdominal muscles relax, the internal organs will protrude outward, and even if there is no excess fat in the abdomen, the lower abdomen will "run" awkwardly. On the contrary, when the abdominal muscles are strong, the internal organs stay where they are, and the abdomen naturally becomes flat and firm. Therefore, in addition to strengthening the abdominal muscle strength, the most important thing to exercise the abdominal muscle group is to return the internal organs protruding outward because of the weakening of the abdominal muscle strength to the original position after the abdominal muscle strength becomes stronger.

Sit-ups do not need to be practiced every day. After each exercise, muscle tissue needs at least 24 hours to complete "reconstruction". Doing abdominal exercises every day does not leave time for the "self-repair" of abdominal muscles, which is not conducive to the growth and shaping of muscles. The best practice frequency is once every two days.