A New View of Responses to First-Time Barefoot Running

Michael Wilkinson

doi:10.23937/2469-5718/1510010

Abstract

We examined acute alterations in gait and oxygen cost from shod-to-barefoot running in habitually-shod well-trained runners with no prior experience of running barefoot. Thirteen runners completed six-minute treadmill runs shod and barefoot on separate days at a mean speed of 12.5 km·h-1. Steady-state oxygen cost in the final minute was recorded. Kinematic data were captured from 30-consecutive strides. Mean differences between conditions were estimated with 90% confidence intervals. When barefoot, stride length and ground-contact time decreased while stride rate increased. Leg-and vertical stiffness and ankle-mid-stance dorsi-flexion angle increased when barefoot while horizontal distance between point of contact and the hip decreased. Mean oxygen cost decreased in barefoot compared to shod running (90% CI -11% to -3%) and was related to change in ankle angle and point-of-contact distance, though individual variability was high (-19% to +8%). The results suggest that removal of shoes produces an alteration in running gait and a potentially-practically-beneficial reduction in mean oxygen cost of running in trained-habitually-shod runners new to running barefoot. However, high variability suggests an element of skill in adapting to the novel task and that caution be exercised in assuming the mean response applies to all runners.

Highlights

The popularity of barefoot and minimalist-shoe running has been steadily increasing in recent years with articles in the popular media and several web sites [1]
In light of current equivocal findings, we examined whether removal of shoe mass and / or gait adjustments could best account for any change in steady-state oxygen cost from shod-to-barefoot running
The likelihood of the true population mean reduction in oxygen cost when barefoot exceeding the smallest-worthwhile reduction associated with improved running performance (4%) was 90%

Summary

Introduction

The popularity of barefoot and minimalist-shoe running has been steadily increasing in recent years with articles in the popular media and several web sites [1]. The hypothesis suggested a sensory-feedback loop where the sensation of vertical and horizontal loading triggers impact-avoidance reflexes in the legs. Lieberman et al [6] found habitually-barefoot runners had a three-fold lower peak-impact force and approximately a twofold lower loading rate compared to habitually-shod runners asked to run barefoot. Vertical-and horizontal loading could be reduced by decreasing the distance between the point of ground contact and the general centre of mass. Reducing this distance could reduce the braking impulse and the magnitude of the associated ground-reaction forces. The differences in gait between habitually-barefoot and habitually-shod runners are consistent with gait alterations that would be expected from the plantar-sensory feedback hypothesis

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