Interpretation of the variability of the steady bipedal posture in age sensitive to the system control

Abstract

 The human postural control study through statistical mechanic techniques identifies dynamic behavior with characteristics of persistence and anti-persistence. Such behaviors are interpreted like time-dependent variability of the control systems, and indicators that reflect these ones, are diffusion coefficient and scaling exponent obtained with stabilogram diffusion analysis (SDA) technique. A force platform was used to obtain stabilometry records and SDA was applied in order to discriminate the temporal behavior of the variability in quasi-static bipedal position in a group of 22 students in critical age (11,2 ± 1,5 years old) for postural control maturity, between eyes-closed and eyes-open conditions. The results of diffusion coefficients (Ds, Dl) and scaling exponents (Hs, Hl) in both visual conditions have two distinct phases from ADE graphic and establish statistically significant differences for Ds and Hs, when comparing the displacement of COP between open eyes and closed eyes. The SDA allows us to identify a behavior of postural control system similar to adults, modeled like a two-phase fractional Brownian motion.