Kinematic Analysis of Trunk Recovery Motion during Slipping

The falls of the elderly are becoming a serious problem, not only medically but also socially. The several study reported recovery movement of the lower extremity during slipping, but the recovery movement of the trunk research reported a few. The purpose of this study was to investigate the balance recovery mechanisms of the separated trunk during slipping with gait. The trunk segment was divided by the upper trunk, the lower trunk and pelvis. A kinematic and kinetic data during slipping were measured by 3D motion analysis system and force platform. Center of mass of the upper body, joint angles and joint moments were calculated by inverse-dynamics method. The results showed that the slip recovery movement needed strongly muscle activation of the upper trunk rather than the lower trunk. The fall prevention requires enough flexor torque of lower trunk for maintaining position between upper trunk and lower trunk. In additionally, trunk constraints group were needed extensional torque for maintaining position lower trunk in the late slip time.