This website provides an introduction to the biomechanics of the human foot, to accompany the research published in the journal Nature on how the overlooked transverse arch of the human foot is a major source of stiffness and how that arch evolved in humans.
When we walk or run, our feet repeatedly push on the ground with forces that exceed our bodyweight. Human feet are so stiff that you can barely see them bend under these forces. Unlike us, the feet of other primates flex considerably. Our study asked what makes the human foot so stiff and how those features evolved. We found that the transverse tarsal arch is a crucial source of stiffness, and a human-like arch evolved at least 3.5 million years ago. Much as a currency bill becomes much stiffer if you even slightly curl it along its width, we found that the transverse arch, which spans the foot’s width, stiffens the human foot. The transverse arch that was overlooked by past research gives considerably more stiffness than the longitudinal arch that was the focus of prior studies. Therefore, our study adds an essential ingredient to the understanding of foot function and the evolution of bipedality in humans. Further research is needed to investigate the impact of the transverse arch on foot health, the design of foot surgeries, or prosthetic and robotic feet.
Note that we did not study foot health and do not present any data on how people should deal with issues such as flatfoot disorders or surgical treatment of foot problems such as in diabetes. Controlled studies and much more data are needed for addressing issues of foot health.
- Why study foot stiffness?
- Biomechanics: What is the source of the foot’s stiffness?
- Physics: What makes a curved sheet stiffer?
- Evolution: How did the human foot evolve?
- FAQ: Related and frequently asked questions.