Measuring Data of Body Sway at Quiet Standing Posture

publisher[Abstract] Quiet standing posture is very unstable state. Therefore person always are swaying even while standing calmly. And such body sways are often estimated from center-of-pressure (COP) measures derived from force plate data. On one hand, aiming at the quantitative evaluation of a carsickness state, we are investigating the influence on this body sway at boarding to cars. In order to know the normal state as comparison data, we put the measurements of body sway about 212 subjects from 3 to 79 years old into practice. Measurements were carried out under the condition whichopened and closed eyes for 30 seconds. Sampling rate was 100s/s and cut-off frequency of LPF was set to 10Hz. From these experimental time series data, we estimated some evaluation indices ; Locus length (a) 34cm б≒15, (b) 44cm б≒21, Area of sway (Rectangular) (a) 3.6cm2б≒ 8.5, (b) 4.4cm2б≒ 9.0, (Mean circle) (a) 0.9cm2б≒ 1.9, (b) 0.9cm2б≒1.2, here (a) stands for under opened eyes, (b) stands for closed eyes. In addition to this, Locus length per unit area, Mean instantaneous speed and Maximum instantaneous speed were also calculated. However, those values are the mean values of overall data. The tendency of the change in index values between opened and closed eyes were different in each subject