Not necessarily. It usually takes about half an hour. It is important to practice every day. Abdominal muscles are special muscles of the human body and need to be practiced every day. Of course, action is also very important. The standard action of supine is that the body is 5 from the ground, and the limit of sit-ups is 85. Remember to pause about 1 sec at the limit points (high and low points) of sit-ups and sit-ups, and don't rely on flashing. What you feel after that is leg pain (not abdominal muscles). It is best to meditate on the rhythm of one, two, three and four (the body is 85 degrees off the ground), then pause for one, two, three and four times (the body is 5 degrees off the ground), then pause for one or two, and then start again. . . , skilled, one group 15 to 20, one group 1 2 minutes interval, about 5 groups at a time.