Transient postural stability of unipedal standing and its parameters evaluation

We recently evaluated the the standing postural stability with the pedobarography (PD) analysis, and assessed the effects of limb laterality, ankle inversion and stabilizer on PPD during unipedal standing. Based on the novel experimental design, in the present paper, transient postural stability (TPS) was defined as an individual's ability to keep balance in a posture for a short time. The definition distinguished it from the static and dynamic postural stability. Nineteen young healthy adults unipedally stood on level or inclined surfaces with ankle inversion (0°, 10°, and 20°). Three ankle stabilizer conditions were designed as barefoot control, elastic tape and semi-rigid brace. Analyzed with multivariate analysis of variance, effects of laterality, ankle inversion and stabilizer were evaluated on the parameters of the anterior/posterior (A/P-FR) and medial/lateral force ratios (M/L-FR), plantar contact area (PCA), foot angle, geometrical center position, the excursion amplitudes of centre of pressure (COP), and the percentage of the plantar force amplitude to the force mean. It was admitted that PD was sensitive to the limb laterality, ankle inversion and protection, and A/P-FR and M/L-FR, and total and local PCAs defined previously could be used to evaluate the unipedal standing TPS. These parameters were more advisable than other parameters which were traditionally used in SPS or DPS evaluation. It would be potentially applied in rehabilitation engineering, or design and evaluation of protective equipment in special occupation.