ABSTRACT
Because falls occur not only in the forward direction, but also in the lateral direction, lateral postural instability may contribute to the risk of fall accidents of community-dwelling elderly adults. The purpose of this study was to determine the relationship between lateral reach (LR) and the lateral excursion of the center of pressure (COP), and their association with self-reported fall incidences.The COP stability limits in LR were recorded using a force plate for 83 community-dwelling elderly people aged 70 years and over with reduced physical functions, who answered a questionnaire for fall incidences in the previous six months. LR was significantly correlated with bi-directional COP stability limits (r=0.57～0.70, p<0.0001). The sum of bi-directional LR was significantly correlated with that of bi-directional COP stability limits (r=0.62, p<0.0001). In the full sample (n=83), people whose LR was equal to or less than 30.1 cm are about 4 times more likely to fall (odds ratio [OR] of fall incidence = 4.15, 95% confidence interval [CI] = 1.31～15.95) than people whose LR was more than 30.1 cm. After adjustments for age, sex, and height, the OR =4.08, 95 %CI =1.11～18.05,(p<0.05).The LR test was found to be a simple and easy evaluation method for lateral balance. LR is associated with fall incidence. Thus, the LR test may be a useful clinical measure for detecting the fall risk of elderly adults.