Four actions to exercise abdominal muscles: sit-ups, supine leg lifts, double-headed leg lifts and suspended leg lifts (the intensity increases in turn). If you can do more than 30 sit-ups, then do sit-ups and leg lifts; If you can do more than 15 supine leg lifts, do it from both ends; If you can do more than 15 from both ends, you can do leg hanging. Practice three times a week, one action in three groups at a time, and each group does about 10. In addition, fat with a body fat rate higher than 10% will cover abdominal muscles. This is why sumo has no muscles. If you have a small belly, you need to jog for about 40 minutes to lose fat. About 3 to 5 times a week. If you can't run for 40 minutes at a time, you can walk for a while.