The foot maintains its shape because of its stiffness as it pushes off the ground with a force of more than twice the body’s weight. The white dots trace the longitudinal arch and are only slightly displaced with each step, reflecting a minor bending of the foot.
Ali Yawar, Carolyn Eng, and Madhusudhan Venkadesan, YALE UNIVERISTY

The transverse arch, which curves across the center of the foot at the heads of the metatarsals from the outside to the inside, is responsible for more than 40 percent of the human foot’s stiffness, according to a study published on February 26 in Nature. The remaining 60 percent arises from a combination of muscles, ligaments, the plantar fascia, and the longitudinal arch, which runs from the heel to the ball of the foot. Most research on mid-foot geometry and foot stiffness has centered on the longitudinal arch, but this study shows...

Foot stiffness, aided by the transverse arch, helped make human locomotion possible, the authors concluded from their analysis of hominin fossils. “The stiff human foot enables an efficient push-off when walking or running,” the authors write in the paper, “and was critical for the evolution of bipedalism.”

M. Venkadesan et al., “Stiffness of the human foot and evolution of the transverse arch,” Nature, doi:10.1038/s41586-020-2053-y, 2020.

Amy Schleunes is an intern at The Scientist. Email her at

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