Standardizing Methodology for Research with Uneven Terrains Focused on Dynamic Balance During Gait

Abstract

This research tested a reproducible uneven walkway designed to destabilize human gait. Ten participants walked 30 times over even and uneven (7.3 × .08 m, sequentially-placed wooden blocks in a rotating pattern, 1-cm thick rubber mat) walkways. A full-body marker set and 8-camera motion capture system recorded limb kinematics. MatLab 2013b was used to calculate measures of gait stability: angular momentum, margin of stability, step width variability, CoM height, toe clearance, lateral arm swing. The minimum number of strides necessary to minimize intraparticipant variability was calculated via the interquartile range/median ratio (IMR) at 25% and 10% thresholds for each measure. A paired t test tested for significance between terrains (P < .05). The uneven walkway significantly destabilized gait as seen by increases in: coronal and sagittal plane angular momentum, step width variability, and toe clearance. We found no significant difference with the margin of stability between the 2 terrains possibly due to compensatory strategies (eg, lateral arm swing, trunk sway, step width). Recording a minimum of 10 strides per subject will keep each variable between the 25% and 10% IMR thresholds. In conclusion, the uneven walkway design significantly destabilizes human gait and at least 10 strides should be collected per subject.