The Tarahumara of Chihuahua, Mexico call themselves "Rarámuri," which means “light feet” or “runners on foot." It is no secret that the Tarahumara can run ultra long distances, but how can they cross the harsh terrain of the Sierra Madre mountains wearing just sandals?
Jessica Lopez, author at Remezcla, explores this answer in her article "Harvard Professor Explains How the Tarahumara Run So Well In Those Sandals."
The article reviews Harvard evolutionary biologist Daniel E. Lieberman's paper. Dr. Lieberman has been highly influential in presenting the social and spiritual context of the Tarahumara running culture.
"According to Lieberman, “Tarahumara who wear huaraches have higher and stiffer arches than those who wear modern, supportive shoes.” He backed this idea on the basis that “several features of modern running shoes, especially stiff midsoles and arch supports, likely decrease how much work the intrinsic muscles of the foot do.” In other words, years of running have made the Tarahumara’s feet muscles and arches that much stronger. Straight up."
Lopez also alludes to both Lieberman's study and Amby Burfoot's Runner's World article and says:
"...according to Runner’s World, stiffer arches could potentially “lead to fewer injuries and more energy-return.” Huarache-clad runners also ran with “high step frequency” and “little to no over-stride,” crucial components to good running form."
While running is complex and drawing definitive conclusions on the Tarahumara huarache sandals isn't simple, the Rarámuri runners who wear them nonetheless enjoy stiffer arches.
Lastly, Lieberman's work in the field has been highly influential and eye opening to the power of context in understanding the social and spiritual elements of the Tarahumara running culture.