Mention barefoot runners and most people's first association is probably the legendary 1960 Rome marathon victory by Abebe Bikilla. To some advocates the conversation can get heated up quickly as if you were talking about politics. The fundamental question that has yet to be fully answered is whether one can accurately track a population of runners who are barefoot vs.shod.
Abebe Bikilla : Barefoot Icon
The story goes that Adidas who was the shoe sponsor for the games did not have any shoes that fit Bikilla by the time he trried on the shoes that were left. Bikilla decided to run the race barefoot as he had trained and won. Of his race he is quoted as saying that “I wanted the world to know that my country, Ethiopia, has always won with determination and heroism." . He did not repeat a barefoot run in 1964 in Tokyo. Part of this decision was attributed to the more industrialized roads in Tokyo. He also was recovering from an appendectomy 40 days prior and still managed to pull off a world record running this time in a pair of Asics.
Barefoot Running from the Savanna to the Track
Anthropologists such as Daniel Lieberman believe that the human foot developed to run barefoot. His hypothesis is that we were built for endurance running. He is doing a study with Vibram Shoes and is currently looking for barefoot runners. Prospective studies and randomized controlled trials of barefoot and shod running are difficult to achieve for obvious reasons. Robbins and Gouw argued that plantar sensation induces a plantar surface protective response whereby runners alter their behavior to reduce shock. The less-cushioned shoe permitted increases in plantar discomfort,a phenomenon that they termed "shock setting" Coaches such as Brooks Johnson and Vin Lananna have used barefoot running as part of an overall program to train the body to run long distances fast. In their opinion, to run properly, the foot needed to grasp and release on a variety of surfaces such as dirt, grass, road, concrete, and gravel.
The Shoe Industry Steps In
Several companies have weighed in with their versions of a running shoe which simulates barefoot running. Adidas approach was to try and copy the shape of the foot. In theory this will produce smaller lever arms which can react faster.The idea for the Nike Free was born out of a visit by a couple researchers to Stanford where Lananna was having athletes running barefoot as part of their training regimen. Many competitive runners I spoke to use barefoot running or shoes like the Nike Free as part of their training. Nike had students test it for 6 months and those using the the Free for 6 months had greater flexibility and strength in the foot. I interviewed Tobie Hatfield from Nike's Innovation Kitchen and Jeff Pisciotta from the Nike Sports Research Lab to find out how the shoe industry has incorporated the concept of barefoot training into their shoe design. They seem to be spearheading the shift back to their spirited roots to the old Bill Bauerman days when they made prototype soles on waffle irons. They studied 20 competitive runners on grass and kinematics analysis demonstrated a general trend towards full foot contact. If you watch the footage of Abebe Bikilla's Rome Marathon you will notice the same thing. The perception of some of the runners tested was that they were landing more towards the forefoot than they actually were. . Many believe that racing barefoot is difficult unless you have been running without shoes all your life. Many recreational runners are also starting to try barefoot running in an effort to prevent injuries and improve technique. The problem with this is that some of them will not have the conditioning to handle the transition to barefoot running. Experts in the field agree that any transition to barefoot running be done slowly.
The running shoe industry has built much of its platform on cushioning. In studies by Benno Nigg ,very soft shoes will bottom out when loaded, producing higher impact forces than firmer shoes that do not bottom out. Yet for any of us who have run downhill on concrete the more cushioned shoes seem to be less jarring so how do we reconcile this? I interviewed Benno Nigg, one of the foremost biomechanics gurus on running shoes and he was able to provide a new paradigm which he has published on. He started by telling me that there is no article in the literature which supports the notion that peak force transmission will be altered with varied levels of cushioning. In fact peak force transmission does not occur during heel contact as we might intuit but in midstance where the internal forces in joints muscles and tendons are 4 to 5 times greater than during impact There is something else that accounts for the perception that we are more comfortable in a certain level of cushioning. That something else is explained in Benno' Nigg's vibration model. When we impact the ground our soft tissue compartments (e.g. calf, hamstrings etc.) start to vibrate. However the human body does not like vibrations. Consequently, muscles are activated to dampen these vibrations. The degree of dampening that occurs in various types of shoes is what leads to our perception of comfort in the shoe. So we have an innate sense of what works for our bodies that is probably more accurate than any test could demonstrate for us. We must also consider the fatigue that occurs within the muscles that are working to distribute the vibrations. We know from other studies that fatigue can lead to injuries and this may be part of the answer we seek.
For runners such as Dave Watts,the director of the American Running Association things have come full circle. He relates that some of the early Tiger shoes he ran in in the 70's were not very beefed up in terms of cushioning. They resembled the more fashionable running shoes you see in boutiques in Brooklyn and West Hollywood. At one point he was running in orthotics prescribed for plantar fasciitis and a conventional running shoe. Now he gravitates towards shoes like the Free. The trend in the shoe industry seems to be toward offering more shoes with more minimalist designs. Keep in mind that for most runners barefoot training is good to train the small muscles that are not trained in stable running shoes.
It is hard to isolate all the force vectors because of the complex arrangement of the joints of the lower extremity. Robbins association between injury and wearing shoes has the possibility that wearing shoes increases the risk of injury, but other explanations are possible; for example, in developing countries barefoot runners may be too poor to seek medical attention, shod runners may wear shoes because they have problems running barefoot.
There appears to be a continuum of preference for barefoot running related to a runner's efficiency and abilities. Certainly runners that have grown up running barefoot in areas where it is more prevalent, like Kenya, have been conditioned to run more efficiently barefoot than more industrialized countries. Beyond that elite athletes are exceptional in their foot musculature and would have an easier time in general running barefoot than others.
A word about zealots on both sides of running barefoot vs shod. Some will experience cognitive dissonance when their point of view is challenged. This means that when presented with evidence contrary to their point of view they will tend to deny it or reframe the evidence as if it was part of their argument all along. We should remember this, otherwise we are no better than the iconic Dr. Zaius who held both the posts of both minister of science and defender of the faith, a conflict of interest that does not seek out answers, only support for our own preconceived views. It turns out for the answers are very individual and may not be what we expect.
Judah Tim, Bikila: Ethiopia's Barefoot Olympian
Barry Block DPM personal communication
Tobie Hatfield Jeff Pisciotta,personal communication
Benno Nigg Phd personal communication citations
Nigg, B. M. and Wakeling, J. M. Impact forces and muscle tuning - a new paradigm ESSR Exercise and Sport Sciences Review (29) 1 37-41, 2001
Nigg, Benno New Ideas and Concepts in sport shoe development
(Robbins and Hanna, 1987). ,
Robbins SE, Hanna AM (1987). Running-related injury prevention through barefoot adaptations. Medicine and Science in Sports and Exercise 19, 148-156
Robbins SE, Gouw GJ (1990). Athletic footwear and chronic overloading: a brief review. Sports Medicine 9, 76-85