Influence of Aging and Movement Speed on Trunk Kinematics during Sit-to-Stand Motion

[Purpose] The purpose of this study was to examine the differences in trunk movement between young and older people in sit-to-stand motion (STS). [Subjects] One group consisting of 19 persons aged under 33 and another group of 21 healthy older persons participated in the study. [Methods] Biomechanical data were collected from force plates (AMTI) and a motion analysis system (Vicon Peak), and we compared the young group with the older group under comfortable and maximum speed conditions. [Results] Significant differences in center of mass (COM) speed, COM-heel distance, trunk movement and hip joint moment were found between the two groups in the maximum speed condition. Trunk flexion and extension movement of the older group decreased more than in the young group, suggesting that trunk movement contributes to production and control of momentum in STS.