Published September 21, 2020
Wearing footwear with an upward curvature at the front of the shoe — known as a toe spring — requires less work from the muscles of the feet to walk than shoes with a flatter sole, according to a biomechanics study published last week in the journal Scientific Reports.
The findings explain why toe springs are comfortable and popular, but suggest that shoes with toe springs may contribute to weakening of the foot muscles with long-term use. This may increase susceptibility to common pathological conditions, such as plantar fasciitis, inflammation of soft tissue in the foot that connects the heel bone to the toes, according to the study’s authors.
“We’re not suggesting everyone abandon their sneakers and go barefoot,” says study second author Nicholas B. Holowka, assistant professor of anthropology, UB College of Arts and Sciences. “But this a design trend that’s common today, especially for athletic shoes, and we want to understand what the long-term effects may be for people who wear shoes with toe springs.”
Holowka, who joined the UB faculty earlier this year, is a biological anthropologist who studies the evolution of human bipedalism and the consequences of this process on musculoskeletal health, including the impacts of recent cultural innovations like shoes.
The study was led by Freddy Sichting, professor of human locomotion at Chemnitz University of Technology in Germany. In addition to Holowka, co-authors include Daniel E. Lieberman, Edwin M. Lerner II Professor of Biological Sciences at Harvard University, and Oliver B. Hansen, who studied under Lieberman.
Toe springs keep the toes continually elevated above the ground in a flexed upwards position to help the front part of the foot roll forward when walking or running. They are present in most modern athletic shoes, but their effect on natural foot function and vulnerability of the feet to injury has not been widely studied.
The research team investigated the effects of toe springs on foot biomechanics using a controlled experiment in which 13 participants walked barefoot on a treadmill at a comfortable walking pace.
The participants were then asked to repeat the process wearing four different pairs of specially designed sandals with varying upward curvature of the toe region in order to simulate the curvature of modern athletic footwear. The team captured 3D motion data using markers placed on each subject’s knee, ankle and foot.
The authors found that toe springs decrease the work of the muscles around the joints that connect the toes to the foot bones. The higher the upwards curve of the toes in respect to the rest of the foot, the less work the foot muscles had to perform to support the joints when walking.