Usually the abdominal cramps occur when doing sit-ups, because the abdominal muscles for a long time, suddenly, a large number of intense contraction and fatigue caused by strong stimulation, and in the past did not engage in abdominal strength training and abdominal muscle training, suddenly a large number of muscle training will also lead to muscle cramps. When doing sit-ups, the body starts the anaerobic glycolytic pathway, and sit-ups are anaerobic strenuous exercise, which will release a large amount of lactic acid in the body, and lactic acid will accumulate locally, and the accumulation of lactic acid in the small abdomen will also cause local cramps, along with soreness, swelling and pain. Patients should not panic when the above situation occurs, take a prone position with two hands on both sides of the shoulders slowly support the upper body back, the abdominal muscles can be restored to a certain stretch, or give local heat or physiotherapy, can relieve the abdominal twitching and spasm.