Hello, I'm a fitness instructor. It is recommended not to do sit-ups as much as possible, because sit-ups are more about exercising iliopsoas muscles. At present, one of the most popular abdominal exercises is called belly rolling. The key points of the exercise are as follows: supine, knees bent 90 degrees, legs parallel to the ground (it is recommended to put the legs on the stool), chin slightly retracted, hands crossed on the chest, fingertips touching the acromion, head and chest slowly raised, elbow joint touching the thigh surface as much as possible (not necessarily at first), and slowly lowered, with 20 groups as a group. We will increase the quantity and improve the quality according to our own progress in the future.