背转双手时,手臂向内向后旋转,上臂的肩端会向前旋出,肩关节相应向前向内扣出,上身重心前移,使上身向前倾斜。为保持平衡,头颈及下巴亦向前伸出,于是显得佝偻,这样的姿势走路,由于重心不稳,稍有不慎就容易摔倒,致骨折或肘部受伤。 When you turn your hands back, the arms rotate inward and backward. The shoulder of the upper arm will be screwed forward. The shoulder joints will buckle forwardly and inwardly. The center of gravity of the upper body will move forward, and the upper body will be tilted forward. In order to maintain balance, head and neck and chin are also extended forward, so look 佝 偻, such a position to walk, due to center of gravity instability, a little careless easily fall, resulting in fractures or elbow injuries.