The effect of gait speed on lateral balance control during walking in healthy elderly.

The aim of this paper was to investigate the effect of speed dependency on lateral gait parameters. In 36 healthy elderly (mean age=72.5 years, S.D.=3.2 years), walking at four different self-administered speeds, mediolateral trunk acceleration and step width (SW), but not step-width variability (SWV), were found to have quadratic relations to gait speed. Normalizing for speed by curvilinear interpolation, and controlling for subject characteristics, disclosed smaller SW (adjusted R2=0.41, P<0.001), but larger SWV (adjusted R2=0.26, P=0.01) with increasing age in multiple regression models. These relations were camouflaged at preferred speed.