Adapting Lateral Stepping Control to Walk on Winding Paths

Abstract

Most often, gait biomechanics is studied during straight-ahead walking. However, real-life walking imposes many turns and/or other maneuvers people must navigate. Such maneuvers challenge people’s lateral balance and can frequently induce falls. Determining how people regulate their stepping movements to maintain balance during complex walking tasks is therefore essential. Here, 24 adults (12F/12M; Age 25.8±3.5yrs) walked on wide or narrow virtual paths that were either straight, slowly-winding, or quickly-winding. From each trial, we computed time series of step widths and lateral positions relative to the path. We applied our Goal Equivalent Manifold framework to quantify how participants adjusted their lateral stepping and step-to-step corrections of step width and lateral position as they walked on these different paths. On the narrower paths, participants walked with narrower steps and less lateral position variability. They did so by correcting step-to-step deviations in lateral position more, while correcting step-to-step deviations in step width less. On the winding paths, participants took both narrower and more variable steps. Interestingly, on slowly-winding paths, participants corrected step-to-step deviations in step width more by correcting step-to-step deviations in lateral position less: i.e., they prioritized maintaining step width over position, likely to maintain lateral balance. Conversely, on quickly-winding paths, participants strongly corrected step-to-step deviations in both step width and lateral position: i.e., they prioritized maintaining both approximately equally, consistent with trying to maximize their maneuverability. These findings have important implications for persons with gait impairments who may have elevated fall risk.