RunningPhysio welcomes a bit of a legend onto the site today! Simon Bartold is a world renowned podiatrist who has won awards for his research and contributions to education. He has 24 years of clinical and research experience which he has distilled into his excellent website. You can follow Simon on Twitter via @bartoldbiomecha. He’s kindly agreed to share his thoughts on selecting running shoes…
Tom has graciously invited me to right this blog for his excellent website, and I am very excited to share my thoughts. But somewhere.. at the back of my mind, I am thinking .. sheez.. I feel like I just got thrown under the bus!! Now why would that be?
Well firstly, because, in my long. LONG involvement with sports medicine, and in particular athletic footwear, I have never known the athletic footwear industry to be more volatile.
A series of cataclysmic events, brought on by the alignment of the Tarahumara Indians with Chris McDougal, and the publication of a paper in Nature Journal, turned the comfortable world we all inhabited, where motion control, neutral and structured cushioning all lived in peace and harmony.. on its head!
Suddenly we were confronted with the awful possibility that cushioned shoes were not necessary , that big elevated heel crash pads were passé, that it was great to run in a weird looking thing called a Vibram Five Fingers, or, most horrible of all, it might be perfectly acceptable to run barefoot! Run…. barefoot!!? Clearly the world had gone completely mad!
In 2009, Chris Mcdougal, a journalist, well, war correspondent to be precise, had written a ripping yarn called “Born to Run”, a “Boys own Adventure” about his experiences with a group of Native Americans living in the Copper Canyons of Mexico. He called the Tarahumara a “super race” of runners who could run huge distances with no or very minimalist, sandal type footwear, never get injured, never get sick, live to a ripe old age, and best of all, in the course of their life’s journey, consume vast quantities of beer! Talk about livin’ the dream!
McDougal followed the course of his adventure until precisely page 167, when he abruptly veered off course, and railed against the evil athletic footwear companies, sprouted some pseudo scientific evidence, and declared that injuries were caused by modern running shoes and that all one needed for a successful running and beer drinking career was either no shoes or a Tarahamara sandal.
OK.. so here is my under the bus moment.. thanks a lot Tom! I beg to differ with Mr. Mcdougal. If indeed the Tarahumara are able to successfully run very long distances, well into old age, without injury, it almost certainly has nothing whatsoever to do with the sandal they wear or lack thereof.
The Tarahumara are a genetically isolated tribe (and we are increasingly understanding the incredible significance of the gene pool and gene expression in injury and recovery), they are small and light, they learn to run at a very early age as play, and they stick to it throughout their lives. They run up hills, they run down hills. They run across hills and through streams and over logs, stony ground, forrest and pasture. All these things are protective of overuse injury, and they are about as far removed from the way I take my daily exercise and the way the average British runner plots his course up and down the High Street, as could be. The Tarahumara never impart the same loading patterns during a run. They are constantly recruiting different muscles, constantly varying the input load. And, if indeed they do not get injured, this is almost certainly the reason, not because of footwear or running barefoot!
Almost immediately upon the release of McDougal’s book, evil forces conspired to thwart the multi-billion dollar footwear industry. An evolutionary biologist from Harvard University, Daniel Lieberman, published an article in “Nature“, entitled, “Foot strike patterns and collision forces in habitually barefoot versus shod runners.”
In this paper, Lieberman proposed that the way a runner struck the ground, i.e., either via the rearfoot or the forefoot, was the main player in running injury, because of the impact load transmitted through the skeleton. He took 3 groups of runners: (1) habitually shod athletes from the USA; (2) athletes from the Rift Valley Province of Kenya (famed for endurance running), most of whom grew up barefoot but now wear cushioned shoes when running; and (3) US runners who grew up shod but now habitually run barefoot or in minimal footwear.
He concluded: “barefoot and minimally shod runners avoid RFS (rearfoot strikes) strikes and therefore high-impact collisions. This may have public health implications.” He then really lit the wick by stating: “The incidence of such injuries has remained considerable for 30 years despite technological advancements that provide more cushioning and motion control in shoes designed for heel–toe running. Although cushioned, high-heeled running shoes are comfortable, they limit proprioception and make it easier for runners to land on their heels. Furthermore, many running shoes have arch supports and stiffened soles that may lead to weaker foot muscles, reducing arch strength. This weakness contributes to excessive pronation and places greater demands on the plantar fascia, which may cause plantar fasciitis.”
Hoooooly COW! Do you think the 4th estate got hold of this one and wrung its neck for all it was worth. Finally.. McDougal says shoes are no good, and now a HARVARD Professor! Yipee! There was barely a day went by, for a whole year, that I could open the paper to not see a glaring headline about how barefoot was best, and if you really were worried about stepping barefoot on a pile of doggie-do, then get the most minimal “zero drop”, no arch support shoe you could find. Do that and you would never get a running injury again.
Ahem… time for a little application of the scientific blowtorch to some of Lieberman’s statements.
- The issue of injury rates not having changed in the past 30 years, despite purported advances in running footwear technology. I think largely, this statement is correct. But it needs to be read in the context that in the 60, 70’s and even early 80’s, if you were a distance runner, you were either very serious, and certainly likely to be coached, or professional. Think Ron Clarke, Frank Shorter and co. Today, the average marathoner is likely to be overweight, culturally deconditioned, and running for a cause or in memory of a loved one. Think… Oprah. Now, if you are still paying attention during this overlong diatribe (I will make some recommendations shortly), you will spot the dichotomy. The average marathon time for all runners in the mid 1970’s was about 3hours and 20 minutes. the average marathon time for all runners today is about 4 hours 40 minutes. Sorry, the cohorts are different, and so to make comment about injury rates over the past 30 years not changing is invalid and unsupportable.
- “Whilst cushioned, high-heeled running shoes are comfortable, they limit proprioception and make it easier for runners to land on their heels.” Hmmm.. I think there may be a misuse of the term “proprioception here’, but never mind. In relation to the shoe making it easier for runners to land on their heels, Lieberman is asserting this is a bad thing. 90% of all runners, land on their heels. I attend “Heel Strikers Anonymous” every second Friday evening and I am proud! At the 2012 USA 10,000 meters Olympic Trials, the very best 10,000 meter runners in the USA were filmed at exactly the same point on the track. One half of these athletes heel struck in a distance racing shoes
- “Many running shoes have arch supports and stiffened soles that may lead to weaker foot muscles, reducing arch strength”. Simply untrue! Weak foot muscles do not cause excessive pronation, in fact the opposite is true. In a foot with complete atrophy of the intrinsic muscles (per Charcot Marie Tooth Disease), the so called “intrinsic minus foot”, rather than becoming more pronated, in the first instance these feet become highly arched “cavus’ feet. There has never been a study demonstrating the association between arch support and weakening of muscles (see here, and here). There have been a few showing arch support strengthens muscles!
- Finally, “weakness contributes to excessive pronation and places greater demands on the plantar fascia, which may cause plantar fasciitis.” Nope.. not even close to the mark. excessive pronation is not associated with the development of plantar fasciitis!
- The fact is there is only sketchy evidence to support the concept that impact or indeed loading rates are important injury predictors in running.
- A very recent study by Kevin Hatala, also on habitually barefoot African runners, found that not all habitually barefoot people prefer running with a forefoot strike, and suggest that other factors such as running speed, training level, substrate mechanical properties, running distance, and running frequency, influence the selection of foot strike patterns. The opposite to the Lieberman “Nature” paper!
OK.. so we could debate this stuff all day, and argue, because the discussion is so polarised. Bottom line is that the whole Born to Run and Lieberman thing has been very beneficial, because it HAS taken every major manufacturer out of their comfort zone. We did see a massive spike in sales of minimalist footwear ( although it is important to note that a definition of this term has never been given, and the category frequently spans the Nike Free, which in my view is definitely not minimalist, to the Vibram Five Fingers, which definitely is), and we also saw some very ambitious claims from some of the manufacturers in their unseemly rush to get slice of a very large cash cow. As a result, to date there have been at least 3 successful law suits brought against minimalist manufacturers, for making performance and injury prevention claims that could not be substantiated. We have now been in the eye of the storm for 4 years, and that is plenty of time for the scientists to take a dispassionate look at what minimalist can and cannot do. Unfortunately, most of the claims have not been supported. Perhaps the one shining light for the benefit of minimalist product is some evidence that it would reduce the energy cost of running. At the very recent 2013 AmericanCollege of Sports Medicine annual scientific meeting, not one, but 7 different papers looked at the issue of minimalism and energetics. Not one of the 7 was able to provide any evidence that wearing minimalist product was beneficial in terms of positively influencing markers of energy cost.
Now.. we come to a very important take home message. NONE of this means that there is not some advantage to wearing a shoe that is lighter, less structured and closer to the ground..aka.. more minimalist. There most certainly are benefits! Going barefoot, or wearing a “zero drop” (that is, a shoe with the same thickness of material under the heel as the forefoot: this may be 0mmRF/0mm forefoot like VFF or 40mm RF/40mm FF like Hoka One One.. still zero drop) shoe, will certainly reduce the external knee joint moments. Assuming the barefoot or shod state produces a forefoot strike pattern. Put simply, a forefoot strike pattern will reduce the load going through your knee, especially to the patellofemoral joint.
So, it would be a perfectly sensible thing to introduce minimalist footwear, or even barefoot training to an athlete who has had recurrent or intractable knee pain.
HOWEVER.. in keeping with one of the fundamental laws of physics, the Law of Conservation of Energy, (energy cannot naturally be created or destroyed), if load is taken from the knee, it goes somewhere else.
And that somewhere, is the triceps surae and the ankle.
Forefoot striking causes a large increase in the external ankle joint moments, and a large eccentric load on the triceps surae.
The bottom line here is understanding how shod or unshod states can be manipulated to train an athlete or assist with a rehab program. Putting an athlete with plantar heel pain into a minimalist shoe, or barefoot, is pretty much a 100% recipe to make them worse. Putting that same athlete in the same circumstance minus the heel pain and plus knee pain may well help resolve the symptoms!
The major issue with minimalist footwear, for those who wish to experiment, is that human naure is strongly biased towards a lack of patience. It is ESSENTIAL that any athlete dabbling in minimalism or barefoot running recognise, that there will be a transition period to acclimatise to the new state and that no-one knows how long this transition period will be. Furthermore, it is not a uniform rule, and as with all things training, it will be different for each individual athlete.
So it is time for me to wrap up and bring it back to the discussion ‘how to advise the athlete”.
Everything has changed. Lightweight product is here to stay, and all companies are investing heavily in design and technology that will reduce weight. To me, this is a gift the minimalist discussion has brought to the table that is worth its weight in gold!
I believe the discussion has also morphed into a chat about “natural running”. Whenever I hear this term I have a picture in my mind’s eye nymphs running through the forest a la naturelle, however I think we can probably be more sensible!
The other real positive minimalism has highlighted is this concept. To me it is not so much a new age philosophy of “natural”, but more having a think about HOW we run. Mixing the input signals for my money is where the future of injury prevention in running will be. And that means ‘natural running’ is about mixing the terrain, the surface, and, the footwear in the course of a week of running.
What is the right shoe? Simple.. there isn’t one, because everyone should, wherever possible have more than one in the kitbag. If you need or want a bit more structure in you running shoe, that’s fine, but a couple of times a week, mix it up with a lighter, less structured shoe for faster, shorter runs. Get onto the trail, and check out the fantastic trail product so many companies are now offering.
Is it possible to match foot type to shoe category? This is a really tough one, especially in the light of a recent study that said it made no difference.
I shall once more disagree and say I think it is very important to assess and understand the runners biomechanics and gait pattern. It is then possible to tailor footwear choices around what you have discovered. That said, I believe the categorisation of footwear into ‘Motion control’, “Neutral”, or “Cushioning” is not supported by the science and is long overdue fo a major overhaul.
So finally, do we throw the baby out with the bathwater and completely disregard what we have learned about footwear over the past 30 years. No, I think not, because whilst aspects of the model needed review, the major concepts were not broken.
The challenge of minimalism and barefoot have underlined this in one way that is pretty hard to ignore. So called “traditional’ running shoe do not, and never have, come with a 15 page manual on how to use them (unlike some minimalist product). In addition, it has never been suggested that there is a transition period required for ‘traditional’ running shoes. Finally, the science has caught up with the hype, and we are simply not seeing the advantages we were promised.
This alone tells a very powerful story, and one that you ignore at your peril!