WALKING IS A HEEL-TOE GAIT – PART 2

napsal Dr. Mick Wilkinson 06 duben 2018

"All phenomena of biology are ultimately obedient to the laws of physics and chemistry… All biological phenomena have arisen by evolution through natural selection." - EO Wilson.

Part 1 of this 2 part series, 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 myth of forefoot walkingThe 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.

References

Holowka, N.B., Wallace, I.J., Lieberman, D.E. (2018). Foot strength and stiffness are related to footwear use in a comparison of minimally- vs. conventionally-shod populations. Scientific Reports, 8, 3679, doi:10.1038/s41598- 018-21916-7.

Wallace, I.J., Koch, E., Holowka, N.B., Lieberman, D.E. (2018). Heel impact forces during barefoot versus minimally shod walking among Tarahumara subsistence farmers and urban Americans. Royal Society Open Science, 5, doi.org/10.1098/rsos.180044.