For more than a century, evolutionary biologists have admired the exquisite design of the human foot and how its features make it possible for us to effortlessly walk upright. Our short toes, for example, enable us to run long distances.

Now, a paper published Wednesday in Nature makes the case that another part of our anatomy—an arch running over the top of the foot—plays a bigger role than previously thought in mobility. The finding increases our understanding of the evolution of foot biomechanics, experts say, and could lead to more accurate robotic and prosthetic feet, help orthopedic doctors treat foot disorders and even inspire better shoe designs.

Called the transverse tarsal arch (that’s the horizontal curve across the top of your