Mechanics of very slow human walking

Amy R Wu,Edwin H F Van Asseldonk,Auke J Ijspeert,Cole S Simpson,Herman Van Der Kooij

doi:10.1038/s41598-019-54271-2

Abstract

Human walking speeds can be influenced by multiple factors, from energetic considerations to the time to reach a destination. Neurological deficits or lower-limb injuries can lead to slower walking speeds, and the recovery of able-bodied gait speed and behavior from impaired gait is considered an important rehabilitation goal. Because gait studies are typically performed at faster speeds, little normative data exists for very slow speeds (less than 0.6 ms{}^{-1}). The purpose of our study was to investigate healthy gait mechanics at extremely slow walking speeds. We recorded kinematic and kinetic data from eight adult subjects walking at four slow speeds from 0.1 ms{}^{-1} to 0.6 ms{}^{-1} and at their self-selected speed. We found that known relations for spatiotemporal and work measures are still valid at very slow speeds. Trends derived from slow speeds largely provided reasonable estimates of gait measures at self-selected speeds. Our study helps enable valuable comparisons between able-bodied and impaired gait, including which pathological behaviors can be attributed to slow speeds and which to gait deficits. We also provide a slow walking dataset, which may serve as normative data for clinical evaluations and gait rehabilitative devices.

Highlights

Human walking speeds can be influenced by multiple factors, from energetic considerations to the time to reach a destination
Kinematic data has been recorded at speeds as low as 0.14 ms−1 1,20, 0.2 ms−1 21,22, and 0.28 ms−1 23. van Hedel et al, who recorded both gait kinematics and electromyographic (EMG) data, reported that muscle activity and joint kinematics changed at speeds below 0.69 ms−1, when they were more poorly correlated to 1.4 ms−1 reference speed1. den Otter et al, who only recorded EMG data from speeds as low as 0.06 ms−1, found that the peroneus longus activity was positively correlated with decreased speeds, indicating a need for lateral balance control[24]
None reported mechanical work measures, such as joint work and work done on the body center of mass (COM), or evaluated them in the context of known relationships established at faster speeds

Summary

Introduction

Human walking speeds can be influenced by multiple factors, from energetic considerations to the time to reach a destination. Because gait studies are typically performed at faster speeds, little normative data exists for very slow speeds (less than 0.6 ms−1). Healthy data is mainly centered around walking speeds faster than those of elderly or impaired individuals[11,12,13] This lack of normative data on healthy gait mechanics at extremely slow speeds may limit assessments of impaired behavior and hinder gait recovery efforts. Healthy gait behaviors at speeds between 0.6 ms−1 and the walk-run transition of 2.0 ms−1 are more commonly measured than speeds below 0.6 ms−1 12,14–16 At these faster speed ranges, gait mechanics typically scale with speed. None reported mechanical work measures, such as joint work and work done on the body center of mass (COM), or evaluated them in the context of known relationships established at faster speeds. Quantities are reported in dimensionless form, with body mass, gravitational acceleration and leg length as base variables

Objectives

Methods

Results

Conclusion