"Professionals who participate in bodybuilding competitions rarely do sit-ups." Shen Chao, personal trainer of Meggie Fitness Center, said. Because when doing sit-ups, erector spinae, multifidus and quadratus lumborum get exercise. Those who need to exercise these muscle groups are those who often sit for a long time, and their waist strength is relatively weak. But in everyone's actual operation, they all hold the back of the head tightly with their hands and push forward to drive the body to sit up. Compared with these muscles, the damage to the neck and spine is too great. "While primary and secondary school students do sit-ups excessively or pose incorrectly, they may not see problems when they are young, but when they grow up, their muscles will be more easily strained and their bone development will have a certain impact." ?