Sit-ups can not only strengthen abdominal muscle exercise, but also stretch the spine. A fitness report in the United States pointed out that adults who do sit-ups for a long time can gain 2-3 cm in weight.
Matters needing attention in sit-ups:
1. Don't exceed 90 degrees when the upper body is pulled up, and don't stick to the ground when it is put down, so as not to relax the abdominal muscles.
2. Consciously let the abdominal muscles exert their strength to complete the action.
3. You can hold dumbbells on your chest to increase your load.