Footwear and Foam Surface Alter Gait Initiation of Typical Subjects.

Marcus Fraga Vieira,Isabel De Camargo Neves Sacco,Fernanda Grazielle Da Silva Azevedo Nora,Dieter Rosenbaum,Paula Hentschel Lobo Da Costa,François Hug

doi:10.1371/journal.pone.0135821

Abstract

Gait initiation is the task commonly used to investigate the anticipatory postural adjustments necessary to begin a new gait cycle from the standing position. In this study, we analyzed whether and how foot-floor interface characteristics influence the gait initiation process. For this purpose, 25 undergraduate students were evaluated while performing a gait initiation task in three experimental conditions: barefoot on a hard surface (barefoot condition), barefoot on a soft surface (foam condition), and shod on a hard surface (shod condition). Two force plates were used to acquire ground reaction forces and moments for each foot separately. A statistical parametric mapping (SPM) analysis was performed in COP time series. We compared the anterior-posterior (AP) and medial-lateral (ML) resultant center of pressure (COP) paths and average velocities, the force peaks under the right and left foot, and the COP integral x force impulse for three different phases: the anticipatory postural adjustment (APA) phase (Phase 1), the swing-foot unloading phase (Phase 2), and the support-foot unloading phase (Phase 3). In Phase 1, significantly smaller ML COP paths and velocities were found for the shod condition compared to the barefoot and foam conditions. Significantly smaller ML COP paths were also found in Phase 2 for the shod condition compared to the barefoot and foam conditions. In Phase 3, increased AP COP velocities were found for the shod condition compared to the barefoot and foam conditions. SPM analysis revealed significant differences for vector COP time series in the shod condition compared to the barefoot and foam conditions. The foam condition limited the impulse-generating capacity of COP shift and produced smaller ML force peaks, resulting in limitations to body-weight transfer from the swing to the support foot. The results suggest that footwear and a soft surface affect COP and impose certain features of gait initiation, especially in the ML direction of Phase 1.

Highlights

To start a new walking cycle, anticipatory postural adjustments (APAs) are necessary for stabilizing the postural perturbation induced by the forthcoming voluntary movement [1, 2]
For resultant center of pressure (COP) variables in Phase 1, barefoot and foam conditions produced significantly increased COP paths (p = 0.002 and p = 0.007, respectively) and COP velocities (p = 0.007 and p = 0.015, respectively) in the ML direction compared to the shod condition (Table 1)
In Phase 2, the only significant difference was found for the ML COP path, where the barefoot and foam conditions produced increased paths compared to the shod condition (p = 0.016 and p = 0.044, respectively)

Summary

Introduction

To start a new walking cycle, anticipatory postural adjustments (APAs) are necessary for stabilizing the postural perturbation induced by the forthcoming voluntary movement [1, 2]. This phase corresponds to the initial single support phase followed by the double support phase of the first step, ending with toe-off of the support foot

Objectives

Methods

Results

Discussion

Conclusion