Stability and Manoeuvrability Interactions During Human Walking Depend on the Manoeuvre Direction

Abstract

AbstractThe interplay between stability and manoeuvrability is fundamental for human walking. Previous research finds conflicting perspectives on how these attributes interact – mechanisms for stable walking can either facilitate or impede manoeuvrability. We postulate that these views can be explained by considering manoeuvre direction. We hypothesize that adopting gait patterns that increase lateral stability will impede laterally-directed manoeuvres but not medially-directed manoeuvres due to body positioning strategies that resist lateral movements but aid in the ability to actively generate medially-directed external moments. Twenty-four participants performed many repetitions of a discrete stepping task involving mid-trial reactive manoeuvres in both a Baseline (no external perturbations) and Complex (random perturbations applied to their pelvis) environment. We found that in the Complex environment all participants increased their lateral margin of stability when compared to the Baseline environment. This resulted in an increase in manoeuvre reaction time and foot placement error for laterally-directed manoeuvres but not for medially-directed manoeuvres in the Complex environment when compared to the Baseline environment. These results support our hypothesis and provide the novel interpretation that the stability-manoeuvrability trade-off during human walking depends on manoeuvre direction.