抄録
The purpose of this study was to clarify the strategy of postural control in frontal plane occurred by lateral shifting of center of gravity, and furthermore to reveal related factors of postural strategy in elderly subjects. Healthy 18 elders and 11 young students participated in this study. Subjects achieved the task which was to shift their center of gravity to maximal lateral position. We measured 2-dimensional position of acromion and ante-superior iliac spine (ASIS) in frontal plane. The maximal torques of dorsi / plantar flexion and medial / lateral rotation of ankle were standardized by % body weight (%BW) and used for evaluation of muscler forces of lower leg. According to the results of kinematic measurements of acromion and ASIS, we classified elders in Hip strategy (HS) group (n=13) and Ankle strategy (AS) group (n=5). We employed statistical analysis to compare these HS, AS, and young groups. Result of multi regression analysis of lateral shift of ASIS showed that the significant factors were inferior shift of Acromion for HS (R2=0.638, p<0.01, r=-0.799), and lateral shift of Acromion and plantar flexion torque for young group (R2=0.433, p<0.03, r=0.658). In conclusion, postural strategy with lateral transition of body weight in elders was namely Hip strategy which was controlled with moving mass of pelvic girdle as a counter mass of scapulary movement. However, a part of elderly subjects seemed to have same strategy to young subjects. Therefore studies with multiple view point including sensory system and brain functions will be needed for the future study.
