Do lateral dominance, body mass, body height and direction of perturbation influence the Lehr's damping ratio, which characterizes the balancing ability on an unstable oscillatory platform?

摘要

An unstable oscillatory platform can be used as a simple measuring instrument for modelling balancing capacity. We sought to determine the effects of (1) lateral dominance, (2) body mass, (3) body height and (4) the direction of perturbation on the Lehr's damping ratio for characterizing the balancing ability of 80 healthy young participants on an unstable oscillatory platform. Tests were performed while standing on both limbs and on one limb (dominant or non-dominant), and the direction of oscillation was anterior-posterior and medial-lateral. The healthy patients were divided into four groups based on body height and into five groups based on body mass. The average value of the Lehr's damping ratio was significantly smaller for participants standing on their non-dominant limb compared to their standing on both limbs or on the dominant limb. The largest difference of the Lehr's damping ratio was 0.014 (2.5%) comparing the groups with different body mass, and it was 0.012 (2.1%) comparing the groups with different body height. A weak correlation was found between the Lehr's damping ratio and body mass (r=0.14) and between the Lehr's damping ratio and body height (r=0.19). There was a significant difference when comparing the Lehr's damping ratio determined from oscillation in the anterior-posterior direction to the Lehr's damping ratio determined from oscillation in the medial-lateral direction (p<0.008). Based in our results the Lehr's damping ratio depends on lateral dominance and the direction of perturbation; however, it is independent of body mass and body height.