Abdominal bulge during sit-ups may be caused by muscular development, obesity, umbilical hernia and other reasons. 1. muscular: often exercise, sit-up exercise, when the abdominal muscles excessive contraction, resulting in abdominal muscles concentrated in one part, there will be a bulging situation, this time you need to pay attention to the intensity of the exercise, do not exercise too much, in order to avoid straining the body. 2. Obesity: when the obese people sit-ups, due to the body abdomen folding, fat will be squeezed and concentrated in the abdomen, there will be a raised situation. If the bulging part is soft to the touch, and stop the movement is not, at this time the patient should pay attention to appropriate exercise, weight loss. 3. Umbilical hernia: middle-aged obese women may be related to the weakening of the tissues at the umbilical ring. A hemispherical hernia block will appear in the umbilicus during sit-up, accompanied by indigestion, abdominal pain and other symptoms. The abdominal bulge during sit-ups discharged physiological factors lead to other than, patients can also go to the hospital to clarify the cause, follow the doctor’s instructions.