When in use, knees kneel on the left and right pads, PP is placed on the lower pad, left and right elbows are placed on the upper pad, and the grip ring in front of the upper pad is held by both hands (only two ears exposed from the grip ring are seen in the figure).

Then use force, the abdominal muscles contract and lift the lower body, lift the left and right cushions and the square cushion where PP sits along the arc guide rail, put it down after rising to a certain height, and repeat the exercise.