"What the--?" This was my first reaction to seeing a runner shod in barefoot attire. These shoes are shaped to the contours of a foot in the same manner that a glove fits the hand; each toe is separated. The sole has no cushioning, no arch and no laces. "Toe-shoes" quickly became enormously trendy, selling in the millions. Their central purpose is to support a different running technique: barefoot running.
Unfortunately, the supposed scientific basis supporting barefoot running is unsound. A new study published last week challenges and refutes two central tenets of barefoot running: the front-foot landing technique and the presumed primal human running style.
Forefoot striking is the heart of the barefoot running idea: landing on the ball of your foot instead of the heel mimics the supposedly "natural" style of human running. This is an example of the all-too-common marketing of "natural" ideas and products. Humans used to know how to run correctly before their technique was subverted by technology and marketing.
The basis of this belief is a 2010 study on the members of the native people of the Kalenjin ethnic group, known for producing a disproportionate number of Olympic medalist distance runners. Researchers observed barefoot Kalenjin runners striking the ground first with the bare ball or front of their foot, performing a shorter and smoother stride. This led to the conclusion that the forefoot strike is a preferred technique for distance running. It also bolstered the idea that ancient human endurance runners ran this way.
New research published this month, however, casts serious doubt on both of these conclusions. The article itself is published in a new open access journal, which means that you can go read it yourself for free. (Aside: Open access publishing is a great thing for science and the public. We should all support it.)
The reasoning of this paper is simple:
A typical runner straps on their Nikes and runs one of three ways. When sprinting for a very short distance, runners tend to land on the front of their foot, near the ball on each step. This allows them to step off again as absolutely quickly as possible. (This video demonstrates clearly.)
When running below sprint, but still fast and short, runners often land on the entire foot at once: the heel and the front landing flat on the pavement or track simultaneously. This balances striking on the front of the foot to enhance speed with landing further back for endurance, which occurs during distance running.
Distance running may require 25,000 footfalls: roughly the amount that a typical runner might make during a marathon. While Usain Bolt’s feet only hit the ground 41 times during a record 100-meter sprint, a distance runner has to land more carefully to avoid injury. A running style adapted for distance prioritizes endurance and safety over speed, striking on the heel and rolling forward to launch again off of the ball.
The Kenyan Daasanach people studied in the new research were seen to exhibit exactly these tendencies: when sprinting they landed on the forefoot. When running at slower paces for endurance, their technique shifted to full foot and eventually heel strikes.
This refutes the previous study, which relied on measurements taken at an average pace of 4 minutes 37 seconds per mile. No one in recorded history has run a marathon this fast; an average marathoner averages 8 to 11-minute miles. The running studied in the 2010 paper emphatically does not represent any marathoners, not even winners or world record-holders. In fact it pertains to almost no endurance runners at any race in the world.
The new study further attacks the argument that barefoot running is the more natural technique. It observes a similar native population and performs similar measurements, but finds that the runners do not gravitate to frontal strike except when sprinting.
Barefoot running proponents say they have found "the best way" to distance run. But like most fads, scientific evidence accrues against them. While barefoot runners may like and enjoy their technique, there is little scientific support for claims that it is any better, or even more natural.