Under normal circumstances, after aerobic exercise for more than 30 minutes, the body fat begins to decompose. Running and swimming are good. If you do sit-ups, your legs must be bent. At the beginning, there were 25 groups and 4 groups in each group. Anyway, until you are exhausted, it will be much better to take your time. The number of times in each group can be accumulated slowly, and it is not necessary to add it when it reaches 50 times/group. Excessive exercise in a short time is easy to get hurt.