부산대학교 도서관

The purpose of this study was to clarify the age-related changes of postural control in initiation of lateral step motions. The participants comprised two groups: a young group of 10 females (mean age 24.3, SD 1.8 years), and an elderly group of 10 females (mean age 60.6, SD 3.7 years). They were instructed to step laterally in short (S10) and long (S20) steps as fast as possible. The variables for analysis contained movement duration, shift of center of pressure (CoP) and center of gravity (CoG), displacement and inclination of the shoulder and the pelvis, electromyography of the bilateral erecter spinae (ES), gluteus medius (GM) and adductor longus (AL). In S10, the weight-shift time, CoP shift toward step side, CoG shift toward support side, inclination of shoulder to supporting side, displacements of shoulder and pelvis to supporting side, and bilateral ES activity were higher in the elderly group. When step length was lengthened from S10 to S20, the young group increased the magnitude of GM activity in the supporting limb and shift of pelvis toward the stepping side. The elderly group increased co-activation of GM and AL in the supporting limb but showed no significant differences in kinematic variables. These results suggest that females apply a safer strategy in the dynamic condition with aging.