Absolute and relative reliability of several measures of static postural stability calculated using a GYKO inertial sensor system

The aim of this study was to analyse absolute and relative reliability of a number of postural static stability measures obtained from a GYKO inertial sensor system in young adults. Methods: The study examined 29 healthy non-athlete young adults. A test was performed for 30 s while standing on one foot, without moving, with eyes open and arms relaxed along the sides of the body. The examinations were performed twice, with a one-week interval. Relative reliability was measured using the intraclass correlation coefficient (ICC) and the 95% confidence interval (95% CI), whereas the absolute reliability was evaluated based on the standard error of measurement (SEM) and the minimal detectable change (MDC). Results: The results of this study showed moderate to good relative reliability scores for all the postural stability measures, with ICC values ranging from 0.62 to 0.70. For most of the analysed variables, SEM% ranged from ca. 10 to 14%. Relatively high SEM% values were obtained only for two variables (Area, Convex Hull Area). Conclusions: The low costs of GYKO inertial sensor systems, the fast and easy installation, the mobility and high reliability of the measurement of postural stability show that it can be effective alternative to stabilographic platforms.