Go, Sprint! Study shows that the curve at tip of shoes may lead to weaker muscles

Rubber shoes on the court, boots in winter, slippers at home—inevitably, different features of footwear have emerged to cater to the needs of human beings. One of these features is called the toe spring, or the upward curve found at the tip of footwear, which serves to bring comfort and ease of walking. However, a recent study has shown that although toe springs bring comfort, they may also lead to undesirable consequences.

Running shoes with toe springs. Retrieved from https://www.podiumrunner.com/gear/road-shoes/how-toe-spring-in-running-shoes-makes-running-easier/. Photo by 101 Degrees West.

A group of scientists, led by Chemnitz University of Technology professor Freddy Sichting, investigated the effects of degrees of curvature of toe springs, ranging from 10 degrees to as much as 40 degrees, on the biomechanics of the feet.[1] Their results suggest that toe springs may weaken the feet and lead to painful foot conditions such as plantar fasciitis.[1]

In their study, 13 participants were asked to walk barefoot and in four pairs of custom-made sandals (varying from 10 to 40 degrees of toe spring curvature) on a treadmill, which was fitted with force plates and an infrared camera.[2] Post-hoc analysis showed that there was a significant difference between the metatarsophalangeal or MTP joint dorsiflexion and the toe spring conditions.[2] That is to say, the force produced by the MTP joints decreases as the curve of the toe spring increases.[2]

Dorsiflexion (raising upwards) of the toes creates tension in the plantar aponeurosis, causing an upward force that brings comfort and eases walking. By reducing moments in the MTP joints, toe springs could inhibit or de-condition foot muscles. Photo from Sichting et al., 2020.

“It stands to reason that if the foot muscles have to do less work, then they're probably going to have less endurance given that many thousands of times a day you push off on your toes," evolutionary biologist and senior author of the research Daniel Lieberman says.[1]

“From an evolutionary perspective, wearing modern shoes that have arch supports, cushioning, and other supportive features is a very recent phenomenon,” Sichting added. “In our research, we were interested in a nearly ubiquitous element of modern shoes that has not been studied before.” [1]

Despite these findings, the researchers clarify that more research is needed and that their study does not establish a direct link between toe springs and plantar fasciitis.[1] However, toe exercises, training shoes with little toe spring, and going barefoot are some things that you may consider.[3] Overall, this goes to show that not everything that brings comfort is good for you.

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References:

[1] Harvard University. (2020, September 17). Curve at tip of shoes eases movement but may lead to weaker muscles, problems: Toe springs in shoes may come at a cost. ScienceDaily. Retrieved September 24, 2020 from www.sciencedaily.com/releases/2020/09/200917181249.htm

[2] Sichting, F., Holowka, N. B., Hansen, O. B., & Lieberman, D. E. (2020). Effect of the upward curvature of toe springs on walking biomechanics in humans. Scientific Reports, 10(1). https://doi.org/10.1038/s41598-020-71247-9

[3] Lovett, R. A. (2020, September 17). How Toe Spring in Running Shoes Makes Running Easier– PodiumRunner. Retrieved September 24, 2020, from https://www.podiumrunner.com/gear/road-shoes/how-toe-spring-in-running-shoes-makes-running-easier/