Question: Enthusiastic netizen A replied that the use of sit-ups plays a great role, because sit-ups of various heights and angles can not only exercise the abdomen, but also stimulate the waist and lower back. But if you want to exercise your abdominal muscles specially, the action of sit-ups will be much better than sit-ups, and the role of sit-ups is not great, at least not as great as that of fitness balls. Enthusiastic netizen B replied that sit-ups are of high value, which can increase the strength of waist and abdomen muscles and reduce or eliminate excess fat and fat in waist and abdomen. Doing sit-ups, sit-ups and leg lifts with sit-ups can not only help men "beer belly", but also improve the problem of sagging waist and abdomen muscles of women, thus achieving the goal of shaping women's outstanding and feminine appearance and figure. (Answer Editor: Yan Yan)