Many foot ailments – plantar fasciitis, collapsed arches, bunions, hammer toes, high ankle strains, and all sorts of other maladies – are exacerbated by the very technology that allowed humans to inhabit the globe: shoes.
Footwear helped humans spread into northern latitudes and eventually the Americas. Today, shoes allow one to play blacktop basketball and hike in the woods after a nor’easter. High ankle boots protect against snakebites in the grasslands of Australia and sub-Saharan Africa. Footwear protects against broken glass at the beach or along city sidewalks. Or it simply allows one to buy something at the store since “no shirt, no shoes, no service.” Without shoes, humans wouldn’t have summited Mt. Everest or walked on the moon. There were and remain an important technological innovation. But as is true for many of our cleaver inventions, there are costs that accompany these benefits.
The bottom of your foot contains ten muscles, arranged in four layers. Some of these muscles maintain the foot’s arch while others are critical for propelling us into our next steps. But most shoes, even the wholesome-sounding “arch-supporting” ones can weaken these muscles. The result is a foot more prone to injury.
The Tarahumara are an indigenous people in Mexico known for their exceptional distance-running abilities. Their sandals are usually made from a piece of car tire rubber and held to the foot with string. Human evolutionists studying the Tarahumara to see how they walk and run also used ultrasound to measure the size of their foot muscles. The Tarahumara have higher arches, stiffer feet, and larger foot muscles than the typical American.
Maybe the Tarahumara are just genetically predisposed to have strong foot muscles? The size of two-foot muscles was measured in 33 runners. Half of the runners trained in their normal, cushioned running shoes. The other half transitioned slowly to a minimalist shoe – more like the Tarahumara wear. After only 12 weeks, the minimalist shoe-wearers had increased the size of the two-foot muscles by 20% and their arch was stiffer by a whopping 60%. Our feet change because of the shoes we wear, or don’t wear.
Not only that, but without strong foot muscles, the plantar aponeurosis – that band of tissue that spans the bottom of the foot – can become over-strained, resulting in the stabbing pain of plantar fasciitis. We have lulled ourselves into thinking that our feet need cushioning to survive.
To boot, shoes no longer just protect the feet. They are gendered symbols of social status, wealth, and power. Our feet pay the price. High-heeled shoes shorten the calf muscles and tighten the Achilles tendon, changing how we walk. Repeatedly squeezing the end of our feet into the narrow, pointed shoe box of a shoe increases the chances of developing bunions and hammertoes. These damaging effects disproportionately impact women’s feet and sometimes require surgical intervention.
ARE BAREFOOT SHOES GOOD FOR RUNNERS?
Aficionados swear by them. But the scientific jury is out
As oxymorons go, “barefoot shoes” takes some beating. Otherwise referred to as “minimalist footwear”, these are shoes designed to mimic the experience of not wearing shoes. Evangelists include Joe Rogan, a podcaster who occasionally blesses followers with photos of his toes splayed out in a pair of Vibram Five Fingers (imagine a rubber glove, but for your feet).
The idea that running barefoot might be good for you took off in 2009 when Christopher McDougall, a journalist, published a bestselling book about the Tarahumara, a group of people in Mexico who run long distances without shoes. These days a whole industry caters to enthusiasts. Vivobarefoot, one manufacturer, says “Modern shoes are robbing our feet of their natural potential.” By returning to something closer to the barefoot experience, the argument goes, runners can improve their health and reduce injuries.
Evolution is one line of argument. After all, humans—and their hominin ancestors—have been running barefoot for millions of years. Shoes have existed for only around 40,000 years, according to an analysis of paleolithic feet. That is not an especially long time in which to adapt. And modern trainers, with their padded soles, elevated heels and arch supports, date back only to the 1970s.
Proponents of barefoot shoes argue that cushy modern footwear gives runners weak feet. For example, over 75% of athletes wearing conventional shoes use a rearfoot strike—when the heel hits the ground first. For barefoot runners, or those in minimalist shoes, the numbers are 40% and 67% respectively, with the rest opting for a forefoot or midfoot strike in which the ball of the foot lands either before or with the heel.
The difference is largely because of shoe design. Chunkier heels hit the ground earlier than they otherwise would. And a cushioned sole protects the heel from the otherwise painful impact of running heel-first. Barefoot runners rely on the foot’s inbuilt suspension system to reduce that impact—a collection of tendons, ligaments and muscles which act as a kind of spring, storing and releasing elastic energy to push the body into the next stride.
Such tweaks to the mechanics of running can have big effects on the body. One small study, published in 2021, found that six months of wearing minimalist footwear can increase toe-muscle strength by 57%. Another, from 2018, reported a 40% increase in just eight weeks. Those accustomed to walking and running barefoot—such as the Kalenjin tribe in Western Kenya—have thicker foot muscles and improved ankle mobility. Barefoot shoes may also reduce load on the knee. And among older people, minimalist footwear has been shown to improve stability and balance.
Supporters say that running in barefoot shoes should therefore mean fewer injuries. But no study has confirmed that. The evidence, both for and against, is inconclusive, with most studies examining only small numbers of people. Some scientists worry about increased loads on the calf and Achilles tendon. Others suggest barefoot running may actually increase rates of injury, particularly on hard surfaces, or if the switch to barefoot shoes occurs too quickly. One ten-week study found almost half of runners making the switch showed signs of bone-marrow oedema—a fluid build-up often caused by stress on the foot. The most important thing is a gradual introduction.” ■
