This article has been reviewed according to Science X's editorial process and policies. Editors have highlighted the following attributes while ensuring the content's credibility: We tend to think of our bones as solid, unchanging support structures inside our bodies, but a recent study from the University of Chicago shows just how much they can change depending on how we use them. Using detailed CT scanning, researchers compared ankle bones from modern people who usually wear shoes and those of Indigenous people who go barefoot and saw significant differences in their internal structures.
The study offers a new way of understanding the evolution of walking in our fossil ancestors by providing reference points for how behaviors shape our skeletons. "A lot of people think the skeleton is a fixed thing, but it's constantly changing during your life in response to your behavior," said Zewdi Tsegai, an assistant professor of organismal biology and anatomy at UChicago and senior author of the study. "So, we're using this plasticity of the skeleton to try to understand how living people vary and then taking that back to fossils to reconstruct behavior." Hannah Farrell, Ph.D. '24, who is now on the faculty at UNT Health Fort Worth, led the study, which was published in the Journal of Anatomy.
She and her colleagues focused on trabecular bone, the spongy latticework of tissue inside the ends of bones. Trabecular bone provides structural support and shock absorption while keeping the skeleton lightweight. Importantly for this study, it also changes in response to physical forces from behaviors like walking, running, jumping or climbing to realign its internal struts and offer more support.
"You can think of it like the Eiffel Tower, where it has all these struts and lattices to provide a very rigid structure," Farrell said. "But the trabeculae are also preferentially reoriented throughout life to continue to provide that same support as the individual faces loading from different behaviors." Farrell and her teammates used high-resolution micro-CT scanning to analyze ankle bones from collections of skeletons. The first group consisted of 40 individuals who regularly wore shoes.
A second group included 13 skeletons of habitually unshod Indigenous people from the Andaman Islands in the Indian Ocean, two individuals from southern Africa and one individual from Central Africa, provided by the Natural History Museum in London. The researchers focused on the talus bone—a central, weight-bearing bone in the ankle that connects the lower leg to the foot. The modern, shod individuals had more trabecular bone in the back of the talus, suggesting that people wearing shoes tend to put more weight on the back of this bone, perhaps from the higher angle of the heel created by shoes.
Modern shoe-wearers also had more trabecular bone on the inside of the talus toward the big toe, hinting at how shoes redistribute weight. In contrast, the Indigenous, unshod individuals had more trabecular bone at the front of the talus, indicating more weight being put on the bone from flexing forward, perhaps from climbing or squatting. "We are seeing quite clear distinctions in the internal bone structure, which was a very nice surprise for me," Farrell said.
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