Although I spend most of my time doing other sports, such as badminton and table tennis, I think swimming is the most physical exercise, which can definitely reduce my stomach, and doing sit-ups is useless. This can only improve my abdominal muscle strength plastically. In fact, running is the most convenient. Swimming is a good exercise. Children in cities should go to swimming pools, while children in rural areas should not go to deep water areas, but to waters they are familiar with.