The paradox of barefoot running

Christopher McDougall’s sensational book Born to Run has been credited for an upsurge of interest in barefoot running over the past year, and its publication probably also explains much of the increased sales and visibilty of the once-esoteric and comment-provoking Vibram “Five Finger” running shoes.  Besides being a paean to the joys of running without shoes, McDougall’s book is certainly one of the best written, most entertaining adventure books of recent memory.  It sucks you in with tales of the mysterious hidden tribe of Mexican mountain runners, the Tarahumara, and an unforgettable cast of hardy and eccentric ultramarathoners. The adventure culminates in two exciting and unpredictable ultramarathons through the wilderness — one in the Colorado Rockies, and the other in the Copper Canyon of Mexico — with the protagonists of the book running shoeless over trails and boulder fields for 100 miles. While I’m not a total convert, after reading this book I’ve adopted a habit of alternating my runs between barefoot, Vibrams, and regular shoes. After some initial soreness, stiffness, and development of calluses, I found that my calves were strengthened in a way that significantly benefited my endurance and speed in running.

Other than recommending this book as a great vacation read or a way to rekindle your passion for running, I’d like to concentrate here on one of its central claims about the biomechanics of barefoot running, because it resonates so strongly with the thesis of Hormetism and Edward Tenner’s theories about the “revenge effects” of technology — and because it has implications that extend well beyond the sport of running. McDougall’s seemingly paradoxical assertion is that running without shoes makes one less susceptible to injury than using modern engineered running shoes, with their high-tech cushioning. Says McDougall: “Running shoes may be the most destructive force ever to hit the human foot.” (BTR, p. 168)   …How can this possibly be true?

Perhaps the most controversial thesis of McDougall’s book is that humans evolved to be long distance runners, and that at some point in our evolution as hunters we exploited this ability to actually run down large game such as antelope–animals that could outsprint us for short spurts, but would eventually tire and give up.  McDougall cites some archeological and biometric evidence, but I’m not so sure I buy this, and I’m somewhat skeptical and weary of the constant invocation of evolutionary arguments to explain just about everything related to diet, health and fitness. It’s just that it is so difficult to verify these speculations, so  I happen to prefer more testable explanations based upon physiology. And in the area of physiology, I believe that McDougall is onto something. The idea that adding padding or protection can hurt or injure us seems to be a paradox–at first glance.  But if we can understand why protective armor has this effect, perhaps it can teach us something about human adaptation that extends beyond the domain of running.

Shoes and foot injuries. Among the many experts McDougall cites, Stanford track coach Vin Lananna has a certain credibility when he states: “I can’t prove this, but I believe when my runners train barefoot, they run faster and suffer fewer injuries…We’ve shielded our feet from their natural position by providing more and more support…If you strengthen the foot by going barefoot, I think you reduce the risk of Achilles and knee and plantar fascia problems.” (BTW, p. 169-170).  Dr. Barry Bates, who directs the University of Oregon’s Biomechanical/Sports Medicine lab, gathered data showing that the cushioning on shoes does not reduce impact on the legs, but may actually promote injuries. To gain insight into why this should be so, consider another study reported by McDougall, this time from McGill University, showing that gymnasts landing on a mat instinctively adjust their landings based on the thickness and softness of the mat in order to achieve balance upon landing. The same thing happens when we run with cushioned soles: “your legs and feet instinctively come down hard when they sense something squishy underfoot. When you run in cushioned shoes, your feet are pushing through the soles in search of a hard, stable platform.” (p. 173). These adjustments are part of the proprioceptive or “body awareness” sensory system that is built into our neuro-muscular physiology. The story is otherwise when running barefoot on a hard surface:

To see pronation in action, kick off your shoes and run down the driveway. On a hard surface, your feet will briefly unlearn the habits they picked up in shoes and automatically shift to self-defense mode; you’ll find yourself landing on the outside edge of your foot, then gently rolling from little toe to big until your foot is flat. That’s pronation–just a mild, shock-absorbing twist that allows your arch to compress.  (BTW, p. 176)

And according to Dr. George Hartmann, a physical therapist trainer to long-distance runners, pronation is a actually good thing, not the defect it has been made out to be by many:

Your foot’s centerpiece is the arch, the greatest weight-bearing design ever created. The beauty of any arch is the way it gets stronger under stress; the harder you push down, the tighter its parts mesh. No stonemason worth his trowel would ever stick a support under an arch; push up from underneath, and you weaken the whole structure. Buttressing the foot’s arch from all sides is a high-tensile web of twenty-six bones, thirty-three joints, twelve rubbery tendons, and eighteen muscles, all stretching and flexing like an earthquake-resistant suspension bridge…I’ve worked with over a hundred of the best Kenyan runners, and one thing they have in common is marvelous elasticity in their feet. That comes from never running in shoes until you’re seventeen. (BTW, pp. 176-177).

So the explanation here is clear: Our skeletons, musculature and nervous systems are highly refined and well-coordinated adapative systems which adjust both instanteously and by means of longer term adjustments to in order handle the terrain.  These “proprioceptive” adjustments take place virtually beneath the level of consciousness, through the exquisite feedback systems of our body and brain. Try to circumvent these systems, and the protective mechanisms will weaken, exposing us to injury.

I’ve checked this out, and McDougall doesn’t seem to be cherry-picking the research to support his biomechanical thesis.  My informal survey of other research found additional supporting evidence:

  • A study by Harvard’s Daniel Lieberman et. al, in the prestigious journal Nature, entitled “Foot strike patterns and collision forces in habitually barefoot versus shod runners“. The study found that “habitually barefoot endurance runners often land on the fore-foot (fore-foot strike) before bringing down the heel, but they sometimes land with a flat foot (mid-foot strike) or, less often, on the heel (rear-foot strike). In contrast, habitually shod runners mostly rear-foot strike, facilitated by the elevated and cushioned heel of the modern running shoe. Kinematic and kinetic analyses show that even on hard surfaces, barefoot runners who fore-foot strike generate smaller collision forces than shod rear-foot strikers. This difference results primarily from a more plantarflexed foot at landing and more ankle compliance during impact, decreasing the effective mass of the body that collides with the ground.”  To see how this works in action, take a look at blogger Karen Given’s interview of Lieberman, who teaches her how to run barefoot and demonstrates how dramatically this reduces the collision forces on her foot and body:
  • A review by Warburton in the Australian journal Sportscience, of foot injuries, which found that “Wearers of expensive running shoes that were promoted as correcting pronation or providing more cushioning experienced a greater prevalence of these running-related injuries than wearers of less expensive shoes (Robbins and Gouw, 1991). In another study, expensive athletic shoes accounted for more than twice as many injuries as cheaper shoes, a fact that prompted Robbins and Waked (1997) to suggest that deceptive advertising of athletic footwear (e.g., “cushioning impact”) may represent a public health hazard. Anthony (1987) reported that running shoes should be considered protective devices (from dangerous or painful objects) rather than corrective devices, as their capacity for shock absorption and control of over-pronation is limited. The modern running shoe and footwear generally reduce sensory feedback, apparently without diminishing injury-inducing impact–a process Robbins and Gouw (1991)  described as the “perceptual illusion” of athletic footwear. A resulting false sense of security may contribute to the risk of injury (Robbins and Gouw, 1991).  Yessis (2000, p.122) reasoned that once the natural foot structures are weakened by long-term footwear use, people have to rely on the external support of the footwear, but the support does not match that provided by a well functioning foot.
  • Additional studies and commentary, summarized in an article “Should you be running barefoot?” in Runner’s World, by the aptly named Amby Burfoot.  Burfoot’s article has a nice historical overview of great barefoot runners over the past century.
  • Barefoot Ken Bob, a somewhat whimsical website devoted to barefoot running as an avocation, which includes research, practical advice, and announcements of upcoming barefoot races.

Finally, here is short video clip that gives a fairly simple explanation of barefoot running technique, featuring aficionado Barefoot Ted, who will be familiar to readers of Born to Run:

This research regarding the adaptive capacity of the foot coheres nicely with the overall thrust of Hormetism, in its confirmation that strengthening of our capabilities proceeds by progressive, periodic exposure to stress, to an appropriate degree and at a rate that allows us to adapt. It may seem paradoxical to some, but the fact remains that our strength is frequently compromised when we resort to crutches or corrective devices in the (misguided) attempt to shield or cushion ourselves from discomforts and shocks.

Technology and paradox. These findings about barefoot running are actually part of a much larger lesson about the paradox of injury, muscular weakening and other adverse consequences that come from an over-reliance on the protective technologies. This larger thesis is in fact the story of a much larger book published originally in 1996 by Edward Tenner: “Why Things Bite Back: Technology and the Revenge of Unintended Consequences“. You might think that a book with that title would be an anti-technology rant. But this book is not that, it is rather an insightful and even amusing look at technology, written by a technophile who does appreciate the benefits of technology, but at the same time was drawn to probe this puzzling downside to our over-reliance on technology. He has pulled together a wide-ranging survey and analysis of what he calls the “revenge effects” of technology, attempting to explain why it is that technologies often backfire in ironic and unexpected ways that tend to undermine their effectiveness. Such a book could go on for volumes if one wanted to catalogue every possible instance of the perverse effects of technology, but Tenner wisely limits his focus to several probing chapters on a handful of especially illuminating fields: medicine, environmental engineering, pest control, the computerized office, and sport. And while he has interesting things to say in all these areas, I would like to pick up specifically on his discussions of sports injuries, which are particularly relevant to generalizing our understanding of the paradox of barefoot running.

Tenner’s discussion covers a wide range of different sports, from high contact sports like boxing, rugby and football, to seemingly benign recreational sports, like running, skiing and tennis.  Football is illustrative of the evolution of a once intensely violent sport. In 1905, a year when there were 23 deaths in intramural collegiate play, President Theodore Roosevelt threatened to ban the sport unless the rules were changed regulating allowable conduct. Later, in 1939, plastic helmets were introduced and after World War II they entirely replaced the thin padded leather helmets used until that point. But this had an unexpected effect:

Where plastic helmets were adopted, players intent on using maximum force to stop an opponent began to use their headgear, with the mouth guard that soon accompanied it, as a battering ram. This intensifying tactic all too often had its own unintended consequence: spinal fracture and paralysis…What seemed to be a technological solution had become an extension of the medical problem…The NCAA banned aggressive use of the helmet in 1976, and injuries dropped…Spearing, the use of a helmet in place of the shoulders to knock down an opponent, is now banned but is still widespread, and not just in professional play.  (WTBB, p. 217)

So protection led to intensification of injury, but this was moderated by additional rule changes. So far, so good. But this reduction in acute injuries was replaced by a more insidious problem, chronic injuries:

While there are fewer catastrophes, most of which result from spearing and other dangerous practices, serious injuries have actually increased with the spread of better protective equipment. From the First World War through the 1950s, only four in ten professional players per season reported injuries that needed surgery or resulted in prolonged absence from the game. By the 1980s, seven in ten were seriously hurt each season, according to a study by the NFL Players Association…The game’s “ballistic” style calls for brief but powerful bursts expressed as joint- and vertebra-jarring collisions far more severe than those of Theodore Roosevelt’s day. The helmets, face shields, mouthpieces, and padding are better than ever, and deaths may be rare, but neither protective nor conditioning technology can prevent damage to the joints. Since massive injections of anti-inflammatory drugs and painkillers make it possible for battered athletes to return to play, the new intensity means trading immediate relief for long-term disability…Knee and hip surgery can extend players careers, but usually only at the price of later pain, inflammation, and repeated rounds of surgery. (WTBB, pp. 218-219)

Football is certainly not unique in this regard.  For example, Tenner makes a similar points about skiing:

The replacement of wood by plastics and composites in the 1950s changed and extended the sport just as dramatically as lifts had done earlier in the century. Gone were the rituals of waxing. And on the way out, it seemed at the time, were the broken bones that once formed part of the folklore of skiing. At first, the new equipment shifted some of the injury from ankle fractures (common with lower prewar boots) to twisting fractures of the tibia. A fall often led to this spiral break of the bone. Then came further improvements. New, rigid plastic boots and bindings employing strong, lightweight alloys were designed to release the legs of skiers at a predetermined level of force…To the extent that skiers are risk seekers, they will respond to safer equipment and more carefully maintained slopes by seeking more dangerous runs and increasing their speed….Protection also leads to greater risk-taking in the slalom event, where skiers voluntarily use protective gear, including helmets, to take a straighter course down the slope…In the days of wooden skiis, the cast-encased leg was a cartoonist’s cliche, but with some reason….ACL sprains now account for up to six injuries a day at large resorts and up to 100,000 annually in the United States. Surgeons can usually repair a torn MCL by stitching ends together: a sprained ACL demands much more difficult techniques, including tendon grafts. (WTBB, p. 224).

The basic message in all of the above is that as protections have increased, injuries have not gone away, but have shifted from the acute to the chronic, and in many cases chronic injuries that are more enduring and difficult to deal with. This message is consistent with the point made on the Rehabilitation page of this blog about the downside of “crutches” such as canes, orthodics, and even eyeglasses.  The difference, in this case, is that these protective aids defeat our intentions in a different context than that of rehabilitation. Instead of impairing our recovery from disability, these protective aids instead make us vulnerable to injury.  (While the distinction between prevention and recovery is important, there is actually the interesting case of Michael Sandler whose RunBare blog documents his story of how he used barefoot running to overcome a serious shattered leg injury, transforming himself from being unable to walk, to running barefoot 80-100 miles per week!)

Protections such as extra support or cushioning no doubt make us safer in certain respects. But while guarding against the strong shocks that can cause acute injury, these very protections can mask the sensory inputs that our body uses to adjust and adapt internally–both in the instant and over time. In doing so, we are making ourselves vulnerable to repetitive stress or other low level chronic injuries that, over time, can become at least as serious, if not more so, than acute injures, because the healing process is not as straightforward.

Lessons. So where does this leave us, and what should we do about it?  Should we always run barefoot and forgo all the protections of padding and modern protective technology when we engage in challenging physical activities like sports? I certainly would not advocate that. But I think the key point here is to be conscious of what we give up by relying on artificial external protections, especially if it means decreasing our reliance on our own internal musculature and nervous system.  We should be wary of getting too far away from contact with our raw senses and physical exertions whenever we pick up a piece of protective athletic equipment, clothing or footwear, and we might consider how to make internal strengthening and perceptual sharpening an essential part of our conditioning when we train and prepare for athletic performance or even to enhance our ability to navigate the ordinary physical challenges of daily life, such as climbing stairs, or lifting groceries or children. In short: beware of “labor saving” devices; the labor you end up saving may actually be have been useful or necessary to your well being!

What do you think?  Please leave your comments below, or visit the Discussion Forum.

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17 Comments

  1. Kate

    Not only do I feel no pain when running barefoot, nor when I’m done, but I’ve found the same thing during tennis! (My family hates it when I do this, but hey, I’m too old to care) I used to have to quit as my knee would start to stiffen up an hour in – barefoot? No tightness, excellent balance!

    My daughter has been have joint pain now that her tennis season has started – I may switch out her Babolat supershoes for some cheap flat tennies that’ll keep her in good form, landing lightly on the balls of her feet instead of slamming around on cushioned heels…

    Reply
  2. Linda

    Wow, Kate. How do you play tennis barefoot without stubbing your toes? Sounds like fun, but I would worry about jamming my toes when I make sudden stops and turns on the court.

    I do like barefoot running – on the beach, when we go there on vacation. But I’ll have to think about doing barefoot running as a more routine way to run.

    Reply
  3. Sand Sock Girl

    Barefooting is lotsa fun. Especially while doing house chores, walking, jogging, etc. And playing beach volleyball. I am also comfortable with barefoot running than running in shoes. Haven’t tried playing tennis yet. You gave me an idea. I am going to give it a try soon.

    Reply
  4. South Africa may be three or so years behind the US of A when it comes to barefoot Running – but I’m there!
    As a teacher of The Alexander Technique ( 22 years) – please note that the experiment started with Brennan, a teacher of this Technique , I am delighted to see all this progress – maybe we humans will evolve ‘back’ into our natural ( Nature’s) design for moving around the earth.
    I look forward to walking shoes changing their designs to conform to the new thinking and scientific support for the barefoot – and , at the very least, thin soled, wide-toed, roomy shoes. All shoes must deform the feet. They need to be designed to fit the structure of the foot – not feet into oft ridiculous, sometimes merely in current ‘fashion’ industry , shoes .
    Look out for my book later this year ‘ THE ART OF WALKING .
    May we all grow in common sense – light of foot – stepping lightly over the earth.

    Reply
  5. Kate

    Hi Linda,

    I must warn you that I play tennis for fun, not competitively! I’ve found that my leg/foot absorb the impact well (of stopping, turning) and I don’t ever land “funny” and tweak my knees or ankles. This is on hardcourt, of course! Let me know if you like it – I think when I wear shoes, the give of the shoe tweaks my muscles and ligaments when I land/turn…My flat adidas seemed ok, but my form went bad, and I was definitely landing on my heel a bit.

    Reply
  6. Reticuli

    Plantar fascia is on the bottom of the foot running length-wise, not on the knee.

    The evidence does not support the claim that it’s the softness of the shoe or the ground that primarily is causing injuries, but rather the heel height, sole-edge shape, sole flexibility, and toe area shape that is causing most of these problems and promoting bad form & injury. True, getting rid of the shoes completely does automatically get rid of these issues too, but it also introduces other ones.

    Shoe cushioning in general may not be reducing impact on the knees and hips, but it certainly reduces impact pressure points and repetitive stresses on the foot itself when done right and in moderation when the design doesn’t violate the above principals. The problem is that most shoes have become over built and too “supportive” & “stabilizing”… the last being a misnomer. Thus losing footwear completely will be an improvement over that when possible.

    Yet it’s not actually that any & all covering or cushioning is the problem. Ironically, it’s the anatomically-correct and even the numerous “retro line” designs from many companies that get back to a sound solution. Also, the original Nike waffle runner, jika-tabi, Asics’ tabi-like space shoe (which looks suspiciously like their first running shoe), Vibrams, even modified surfing shoes… are all potentially in the right direction.

    And the Tarahumara Mexican natives that McDougall wrote about do not actually run barefoot. They run with a cushioning and protective sandal made from used car tire rubber. That’s a shoe in the “good” category, as it meets most of the criteria above. People who are completely unshod their whole lives, though, have forefeet and middle toes that don’t look much like those of shod people, and they certainly do not run on pavement if they can help it. Theirs is an adaptation that is both representative of their gene pool and a result of years, even decades, of conditioning barefooting.

    Even if you’ve got the feet for it, don’t expect to adapt in just a few months… let alone think all your problems will disappear if you choose to do so on pavement. The guy who recently did that ultra-run for cancer and broke some kind of known “record” in the USA; his feet had lesions, bruises, and severe swelling afterwards. He’s been true-barefooting for years and was running on a softer high school track, not pavement.

    If you go for it, do so very slowly and gradually, and don’t completely write-off all forms of footgear as being made equal… especially if you encounter forefoot and toe problems during the transition. All shoes are not created equal, and neither are feet.

    Reply
    • Todd

      Thanks for the good observations and caveats, Reticuli. You also found a typo in my transcription of the quote from McDougall — I had left out the word “and” between “knee” and “plantar fascia”, which would have made no sense, so I fixed the typo.

      Reply
  7. David I

    I invariably injured my knees whenever I ran, and sports doctors told me, “Some people just aren’t built for running.”

    The problem turned out to be the fact that whenever I became tired, my form became sloppy, and I would take longer strides and crash down on my heel–murder on the knees.

    Once I started running in Vibrams, the feedback from my feet kept me running with rapid, light steps–even when I get tired.

    People who have greater native running talent than I might not benefit as much. But for me, Vibrams changed the whole game.

    Reply
    • Todd

      David,

      Your story is a very encouraging one. Like you, I’m an average runner. I’m training now for a 200 mile 8-person relay and I’m using my Vibrams for about half of my training runs. In addition to improving form, as you suggest, I find that running in Vibrams or barefoot really strengthens my calve muscles, which I think also helps cushion some of the impact from the knees. I also think that a relatively low carb, anti-inflammatory diet with plenty of omega-3 fatty acids from fish helps keep knees and joints in good shape.

      Todd

      Reply
  8. David I

    The best running advice I’ve received was when someone on a forum suggested that we should run “as silently as posible, like you’re trying to sneak up on someone at high speed.” The result is a springy, rapid pace that makes a lot of use of the foot’s natural recoil energy.

    As you say, barefoot/minimalist shoe running is a great calf strengthener. But also a great calf stressor (which I gather would stand to reason, hormetically speaking): the majority of pains and injuries reported by barefooters seem to be strains or overtensioning of the calves. (Achilles tendon issues are a close second, especially for people who have walked for years in shoes with substantial heels.)

    200 miles? Even with 8 people, that’s some serious mileage.

    Reply
  9. Mark

    I noticed that she was not an overpronator, and she also had straight knees. That pretty much means that any shoe would work well on her feet.

    I would love to see barefoot advocates do reports on runners with less-than-perfect biomechanics — such as knock knees. Sadly, I have yet to find any information that provides hope to runners with knock knees.

    Reply
  10. lloyd hunt

    Love all your articles. I want to hike barefooted and used to but I can’t not wear shoes 24/7 and when at work and places I have to wear shoes and my feet soften up so they never get tough enough to handle anything. How can I keep my feet tough while not not wearing shoes 24/7? I’m sick of hiking while going ouch ouch all the time. Any suggestions?

    Reply
    • Todd

      Lloyd – Three suggestions:

      1. Get some stylish minimalist footwear or Vibram FiveFingers and wear those at work and inside. They may get a few funny looks and smart comments, but they’ll keep your feet fresh and working out between your outdoor hiking sessions.
      2. Go for a few weekly barefoot runs or walks to keep your calluses tough.
      3. Check out Justin Owings excellent site on minimalist footwear, birthdayshoes.com

      Reply
  11. lloyd hunt

    Thanks for your reply. I have some VFF and love them. People always say ‘wow I like your shoes.’ But no smart asses so far. My only problem is the bottom of my feet get soft so FAST. I do barefoot walking some during the week but it softens so fast I can’t seem to keep it up. I’ll try running maybe that’ll toughen them up quicker and longer. By the way loving all your articles. It makes me love the internet. So much knowledge.

    Reply
  12. Tim Lundeen

    Re our evolution as persistence hunters, see this video, which shows a bushman actually doing this: http://www.youtube.com/watch?v=826HMLoiE_o&feature=youtu.be

    If you look at the paper by Bramble & Leib that lists specific adaptations that make this possible, it is pretty persuasive. See http://www.clas.ufl.edu/users/krigbaum/proseminar/Bramble_Leib_2004_nature.pdf

    Reply
  13. Max

    Hello!
    I read things about barefoot running last year and found it quite intriguing. According to theory this makes perfect sense. But how is it about people like us who were not raised up without shoes? Can switching our shoes really help? I found this study:

    Ryan et al. (2013): Examining injury risk and pain perception in runners using minimalist footwear:
    http://bjsm.bmj.com/content/early/2013/12/19/bjsports-2012-092061.short?g=w_bjsm_ahead_tab
    They compared running shoes, nike frees and vibrams. Running shoes did not lead to many injuries, but the nike frees did.

    Reply
    • Todd

      Max,

      Thanks for the link to the Ryan article. I will grant that it does present some evidence that semi-minimalist shoes carry some risk of injury. So it’s not a black and white matter. Minimalist running may not work equally well for everyone.

      However, I found this discussion of the Ryan article by Peter Larson to be worth reading:
      http://runblogger.com/2013/12/do-minimalist-shoes-increase-injury-risk-merry-christmas-vibram.html

      Larson points out that the study looked only at runners who did not have prior experience with minimalist or barefoot shoes, so at worst it is a study about the transition to minimalist or barefoot running. He also points out that the fully minimalist shoes had no more injuries than the standard shoes, and that the subjective differences in pain were minimal. In fact, the pain was mainly in the calf. This is in fact what I experienced initially, but the pain was transitional and went away after a month. My calves are very strong as a result, and I now run almost exclusively in minimalist footwear, with no pain or compromise in speed or distance.

      The title of a study often biases interpretation of the results. It’s sometimes a matter of what you choose to emphasize. As Larson points out, “You could just as easily turn it around and say that this study supports the notion that wearing a highly cushioned shoe provides no injury protective benefit over a shoe with virtually no cushion at all.”

      Thanks again for sending this!

      Todd

      Reply

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