„All phenomena of biology are ultimately obedient to the laws of physics and chemistry… All biological phenomena have arisen by evolution through natural selection.“ (E.O. Wilson)
Walking (even barefoot and in sandals) is a heel-toe gait.
Last month’s post described the physics determining the energy cost of walking and the adaptations in the structure of human feet and legs shaped by natural selection to minimise that cost. Despite this evidence, there are still many that believe the heel-toe pattern is not how our ancestors used to walk, especially when barefoot. A recent study shows that barefoot or not, walking is a heel-toe gait (Wallace et al., 2018).
The study, led by Harvard Professor Dan Lieberman, compared walking patterns in habitual sandal-wearing Tarahumara Indians and habitually-shod Americans, walking both barefoot and in traditional Tarahumara sandals, or the modern equivalent. While both groups impacted the ground more gently when barefoot compared to in sandals, everyone used a heel-toe gait in both conditions. The authors suggested that “human bodies have long been adequately adapted to withstand the low-magnitude, high-rate and low-impulse impact of walking over a lifetime” (Wallace et al., 2018, p9).
Though the study showed loading rates (but not the heel-toe pattern) were different between barefoot and sandals, it is worth noting the evidence that sandals can strengthen the feet. Indeed, a retrospective study of Tarahumara and Americans showed sandal use throughout life to be associated with stronger foot muscles and stiffer feet during walking, both of which might protect the feet from the repetitive loads of walking (Holowka et al., 2018).
In summary, and in agreement with the previous post, walking, whether barefoot or in sandals and regardless of previous experience of either, is consistently a heel-toe gait pattern.
Dr. Mick Wilkinson, PhD, MSc, BA (Hons)
Northumbria University, Newcastle, England
Senior Lecturer in Sport and Exercise Science & Department Ethics Lead