Directional ratio: a proposed new variable of dynamic balance regai

Abstract

The use of a free oscillating platform for balance training is widespread. However, there is a lack of variables used when analyzing these measurement results. The aim of this study was to introduce and evaluate a new variable. The directional ratio is the ratio of total length of oscillation travelled in the direction parallel and perpendicular to perturbation, respectively. 21 adult figure skaters (m. age 28) participated in balance regain tests, adopting two-legged and one-legged stances on each leg on the PosturoMed platform (Haider Bioswing, Weiden, Germany) with a medial-lateral perturbation. Overall the directional ratio showed weak correlation with the damping ratio (r = -0.05) and the time of balance regain (r = -0.08), suggesting new information content. One-legged stances had significantly lower damping ratio (p = 0.013) and directional ratio values (p < 0.00), showing more anterior-posterior movement and elliptical trajectories. Using the damping and directional ratios together, balance regain can be better characterized in the future.