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Saturday, March 31, 2012

Vibram shoes named in lawsuit: The danger of barefoot running

Vibram Five-finger named in lawsuit - zealousness, unfiltered advice creates more problems than it fixes

I received this link from a reader yesterday, which explains how Vibram USA Inc and Vibram FiveFingers LLC are part of a lawsuit where it is being alleged that they made "deceptive and misleading statements about the benefits of barefoot running".

It is alleged that the company, which makes the now famous Five-Finger shoe (pic on the right) have made deceptive claims about their health benefits, and this is leading to increased injuries among runners who make the switch.

The problem - the "skill" of barefoot running was not recognized

There is even some research as part of the lawsuit - the American Council of Exercise is carrying a report of this study, which finds that many people who make the switch continue to land on their heel.

Why is this potentially bad?  Well, the graph below, taken from a study on the ACE website, shows the loading rate in three conditions - barefoot (blue column), in Vibrams (purple) and in normal running shoes (green).

What should be immediately clear is that when you look at runners who land on the forefoot (shown by the cluster on the left) the loading rate is lowest when barefoot and highest when forefoot.

However, when you look at runners who land on the heel (right cluster), their loading rate goes in the other direction - here, the barefoot runners who heel strike have loading rates that are about double those of shod runners who are landing on the heel.  This is the effect of the big cushion under the heel of modern running shoes, and it serves to dampen the impact and reduce the loading rate significantly.  Vibrams lack this cushioning, on so fare only marginally better than the pure barefoot condition in heel-strikers.

Those of you who have followed this barefoot running debate will immediately recognize that this finding of impact force differences is not new at all.  In fact, it was found by Daniel Lieberman in a paper published in Nature about 2 years ago.  Lieberman's differences were even more striking - he found that if you run barefoot and land on the heel, then your impact forces are seven times higher than if you land on the heel in shoes.

The graph below is one that I redrew using Lieberman's data and put on this website when I reviewed the barefoot running phenomenon last year.

Now, having said all this, it's important to find the balanced, evidence-based view and be transparent about some "limitations" in these studies.  The first is that the link between loading rates and injuries is not as tight as many would think.  Certainly, higher loading rates have been associated with certain conditions (bone stress injuries being the main one), but the precise aetiology of how injury develops is far more complex than simply saying "if you reduce loading rate, you won't get injured".  Truth is, you might just get a different injury, especially if you start running on the forefoot because you see these graphs!

Then secondly, I'd like to see the study above published in a peer-reviewed journal, only to see the methods in a bit more detail.  Lieberman found a pretty large difference (7-fold) whereas the latest study finds a 2-fold difference between shod and barefoot runners when heel-striking.  That, plus the exact percentage of runners who continue to heel-strike, as well the 'training' they did for the two-week training period, would be of interest to me in order to understand exactly what is being measured in the laboratory.

On that note, Lieberman found that 83% of habitually shod runners were still heel-striking when barefoot.  The ACE study is saying 50% are still heel-striking, even two weeks into running with the minimalist shoes.

Now, that flies in the face of the popular literature, which tells us that when you run barefoot, you switch automatically to an apparently amazing cushioned forefoot running style.  That doesn't seem to happen, though, and the vast majority of people seem to take a lot longer to make this transition than the books (Born to Run is the main one) suggest.

The skill component

In fact, I believe this leads to the most intriguing question of all - understanding the skill of barefoot running.  The ACE study, mentioned above, had the runners do a 2-week "familiarization" period in the Vibrams, where they were asked to run for 20 minutes a day in an attempt to get them accustomed to it.  It's easy to criticize this period as too short and insufficient (all the stuff those who've already made up their mind can say - no study is perfect, remember).

But this two-week adaptation period may partly explain why Lieberman found that 83% of his shod runners were heel-striking when barefoot, whereas the ACE study found that "approximately half" were heel-striking.  Perhaps two weeks of familiarization was responsible for the shift of more runners (1 in 2 rather than 1 in 6) to a forefoot strike, as they 'learned' how to run.

The real question, however, is why the other 50% didn't make this adaptation?  And whether they would given more time? Are there some runners who would never succeed?  Who are they, and what distinguishes them from those who do succeed?  I strongly suspect that some people CANNOT adapt to barefoot running, that they don't have the necessary "skill" to improve the way they run barefoot and change what is years of shod-running-induced motor patterns.

Of course, this is an unanswered question, but I think it's the most important one that needs to be answered right now.  Just as one would not expect anyone who picks up a tennis racquet or a golf club to even become competent at playing it (especially later in life), I don't think it should be expected that simply making the transition to barefoot running will be sufficient either.  Everyone can improve, certainly.  But can they good enough to overcome or avoid what are some pretty clear "risks" associated with the transition?  Remember, in running, unlike tennis or golf, it's not good enough to simply improve over time, because if you don't improve enough, you get injured, so there is a "minimum required improvement" to make the transition to barefoot or minimalist running viable in the first place.

Coaching - sound in theory, but another risk in practice

Here, one can begin to introduce the concept of coaching, that barefoot running (or any running, for that matter) should be taught as a skill.  And certainly, this would help.  In the same way that my tennis or golf game will improve faster if I'm guided, running ability will too.  However, I don't think this will overcome what, for some people, may be a "skill deficit" that will prevent them from succeeding at barefoot or minimalist running.  Again, this is an unanswered question, at least for now.

The other issue, which I raised above, is that there is substantial risk associated with making any change in running technique.  This distinguishes running from, say golf, where wrong technique means lots of lost balls and frustration.  In running, failure to find that apparently elusive "correct running technique" equals disaster.  And what makes it even more tricky is that there's no feedback until the injury - unless you have fancy high speed cameras and force plates to analyse how you run, the first sign of the mistake is often injury.

So if you are going to advocate that people should run barefoot and then coach them so that they learn the right way to do it, then you'd better be certain that you'll make them good enough to avoid the risk - there is a minimum threshold, and if a runner fails to reach it, you've led them to injury, despite good intentions.  And it's not fair to runners to say "Run barefoot" and then blame the runner for their failures.

It's not simply about forefoot landing - even more danger lurks there

To illustrate this, the one thing that many will take out of this study is that it's the forefoot landing that will make the difference.  That is, if you land on the forefoot, you'll be fine.  And in theory, this is borne out by the evidence shown in the two graphs above.

However, in reality, it's a little more complex.  One of the authors of this ACE study is quoted as saying "Buying these Vibrams and continuing to land your heels is probably worse than wearing shoes because the Vibrams don’t have any cushioning. … People may need very explicit instruction and time spent practicing how to land on the ball of the foot. Otherwise, they may be doing themselves more harm". 

I think this is advice is probably MORE DANGEROUS than not saying anything, because as soon as you give an explicit instruction, you put the runner into the compromised situation where they are now focused on a forefoot landing. How do this achieve this?  They planar flex - point the toe away from their body, and drop more than three times their body weight down onto a contracted calf muscle in a compromised shortened position, about 400 times every kilometer.  That's a recipe for disaster, and so the most common problem associated with barefoot running is Achilles and calf related injuries.

Therefore, you can't "instruct" a runner to avoid the risk.  If anything, you instruct them into risk.  Bad idea.  The key, I believe, is to let the skill be acquired gradually, using a few drills to guide the athlete without ever changing their technique "manually", so to speak.  But here again, nobody really knows what works and what doesn't.  We don't even know what constitutes "good technique", and so to simplify it down to which part of the foot hits the ground first is also wrong.  And that's why it's reckless to advocate anything.  At this stage, everyone is learning, and so advocacy has no place, in my opinion.  It's all about education for now.

Extremism:  the media are more to blame than Vibram

Final point re "responders" and "non-responders".  Because we don't yet know who belongs to each group, I think it's reckless and irresponsible to treat them all as potential responders.  The prudent thing to do would be to assume the "worst case scenario", that everyone is a non-responder who needs serious time and intense work and lots of practice.  And then start from this point, and if a runner adapts faster, so be it, that's good news.  Instead, the media and advocates of barefoot running assume that everyone should make the switch because everyone will benefit.  And the bodies left behind will be dealt with later.  It's just too aggressive, too extreme.

And on this note, the media have propagated the myth far more even than the shoe companies like Vibram have.  Vibram are trying to sell shoes, and so they make claims as part of marketing strategies to differentiate their product from their rivals'.  That's normal.  And I can't comment on the specifics of the lawsuit - maybe they're guilty.

But I do know that the media have done a poor job of providing education on this topic.  With a few notable exceptions, they have allowed themselves to become a platform for the advocates of barefoot running without providing the necessary education.  Lieberman's paper illustrates this - he titled that research study "Foot strike patterns and collision forces in habitually barefoot versus shod runners".  The word "habitually" was in there for a reason.

But when the media got hold of that study, they reported only that barefoot running was excellent because it reduced loading rates 7-fold.  This study "proved" the benefit of barefoot running.  Quickly, the "extremists" (my pet hate in all matters of sports science) jumped on this said "It proves our point" and the study's other findings were lost in the aggressive or uninformed interpretation of the data.

This is an eerily similar thing to what happens when it comes to dietary advice.  Recently, I've been involved in debate back here in SA about paleo diets, low carb diets, high carb diets and the like.  And once again, it's a situation where people seem to become over-zealous, finding a cause for which they appoint themselves the spokesperson.  Their success, which is either isolated (1 in 100) or common (1 in 2, perhaps, but never 100%) becomes their proof, and they start telling the world there is only one way to succeed.  "Follow me to change your life" is the message, whether it's barefoot running or eating like a caveman supposedly did.  They thus make the mistake they accuse others of making, by lumping everyone into the same group.

And here, those who succeed become loud, outspoken (and dare I say, obnoxious), whereas those who fail slink away into the background and remain quiet about their failure.  So those who tried barefoot running and got injured disappear, those who succeeded often find a soapbox, write a book, and shout about it.  Those who try low carbohydrate diets and fail revert back to routine with minimal fuss, whereas those who succeed feel the need to tell the world.  They dismiss any research study finding that challenges their position as "corrupt", "incompetent" and "garbage", and so debate goes nowhere.  Once again, this happens because of aggressive advocacy, when it should be about education.

Prescribing a treatment for a condition we don't understand, without knowledge of risk or benefit

Which brings me to the final point.  The big issue, I believe, is that people have become carried away with barefoot running as a way to treat injury and potentially improve performance without really appreciating how it might work (or, importantly, that it may not).

The result then is that barefoot running has taken on the characteristics of a medicine or a drug - it is dispensed by "experts" (who often change their names to "Barefoot X") as a "treatment", but unlike drugs, there are a few key things missing:
  • We don't know which conditions (injuries) the treatment will be effective for.  And by definition, this means we can't say when it will be ineffective
  • We don't know what the correct dosage is
  • We don't know how to phase the dosage in over time for different people
  • We don't know whether the "treatment" is effective for everyone, or whether there are responders and non-responders
  • We don't recognize the possible "contra-indications".  When you take a powerful drug prescribed by a doctor, he knows to check for certain conditions - pregnancy, allergies etc.  For barefoot running, nobody has thought about this
  • What is the effect of other factors on the success of the 'treatment'?  For example, how does fatigue, terrain, muscle weakness, flexibility, strength etc impact on the success of the outcome?
  • As a result of all of the above, we are in a very poor position to quantify the risks, and the "cost-benefit" of barefoot running.
The point is, all the answers, which are pretty important, that you can read on the package insert when you get prescription medication, are unknown for barefoot running.  Yet it is still prescribed 'recklessly'.

And for this, I completely blame the polarization of the debate that allows extremist views to develop and thrive.  It's perfect for the media and the 'zealots' who try to force their success on large groups of people without being open to the other side.  And there are some who are more moderate - I apologize for lumping everyone together.  But there are many who are not.  They base their 'prescription' of barefoot running on their own success story, or at best, a group of runners who they have succeeded with, and suddenly, the entire running community is being told to take this "drug".  It works.  Maybe.  In some people.  If they get it right.  Possibly.  That's not good enough.

And what's worse is that when it doesn't work, when they get injured, then it's their fault.  To return to the medication analogy, this is like giving a drug out to a sick patient and then hoping they get the dosage right.  And even if they follow the instructions to the letter, they may fail, and then it's their doing.  They must have done something wrong.  That's not a viable drug.  It's not a viable "product", and until that is recognized, I would caution all runners to be a little more prudent about how they advise others, and about following advice they receive.

The golden rule in science should be that polarization should be regarded as highly suspicious.  There are very few things that are known with absolute certainty, and when you're dealing with incredibly complex human physiology, the individual differences that make us who we are, what we're good at, how we run and what we eat, for example, are so vast and complex that nothing can be polarized without being wrong!  So when someone says "It's all about training, genes don't matter", they're just as wrong as someone who says "It's all about genes, training is irrelevant".

Similarly, barefoot running is not "the answer", but nor is it bad.  Carbohydrates are not evil, but nor are they the best option for some people, as evidence is now showing.  An individual approach is the only accurate way to go - it's not great for the media who love the sensation, and it's not great news for the gold-diggers who want sensation to sell books, but that's the reality.

Barefoot running - where does it leave us? Opinion and exploration

And so for barefoot running, where does that leave us?  Again, this is my opinion, based on the evidence and my own current research (I have two research studies underway, looking at various aspects of what I've discussed in this and other posts - results in a year or so!).  However, I'd say the following:

In a group of 100 runners, every single one will benefit from barefoot running as a training method.  It changes muscle activation patterns, strengthens muscles and tendons that we don't activate nearly as well in shoes, may be an effective form of rehabilitation, and it's really enjoyable.  So I would say that everyone should incorporate some barefoot running into their training programme.  Whether it's a 2 minute warm-up, an easy 30 min jog once a week, or some sprints after training, I'd say try it out and feel the difference it makes.

However, it's probably not for everyone.  Practically, theoretically, logistically and for many other reasons, some people will not take to barefoot running well enough for them to become 100% barefoot runners.  However, for others, it may well work.  It may prove to be the answer to your prayers, and the secret to injury-free running for life.  That's fantastic, and so you should embrace it and do it with enjoyment.  But don't believe that because it helped you, it must be used in the same dosages by everyone else - they may not have the same "condition" as you, they may have an entirely different history and thus set of contra-indications, and your enthusiasm, however well intended, will cause more problems than it solves.

You may sit on one of the poles - either north or south, either a responder and great barefoot runner, or a non-responder, and classic shod runner.  Which is perfect for you, but remember, between those poles, there's a world of people who are different, and so your extreme position in the complex spread of physiology shouldn't produce an extreme advocate for anything.


Thursday, March 01, 2012

10,000 hours vs training debate: No scientific limits making it impossible for any individual to become an elite athlete with practice?

Dear Anders Ericsson...a request on behalf of sports science to stop telling people that the world is flat

The 10,000 hours vs genetic debate, and correcting Prof Ericsson's mistruths 

So last night, I was (un)fortunate enough to be involved in a radio debate with Prof Anders Ericsson on the concept of talent vs training.  For those who don't know, Ericsson is the father of the 10,000 hour concept, where he prescribes that ANY individual can become an elite athlete if they engage in the required hours of deliberate practice.  He sets that number at 10,000 hours, which is really more marketing than it is science, and I had the chance to "debate" this on air last night.

Unfortunately, the debate ended before I was able to adequately respond to some of Ericsson's claims, and so this is a post to do just that - respond, put the sports science side of the debate across.  I address the article to Ericsson somewhat tongue-in-cheek, and I don't mean to appoint myself on behalf of sports science, but the truth is that someone has to point out that the books, the popular media, and Ericsson are misrepresenting the evidence (either deliberately or ignorantly).  And besides, Ericsson did ask in the radio interview (see below).

The debate was a glorious seven minutes long (I was told it would be much longer), and it involved two opportunities for Ericsson to state his case, and two for me to try to explain the physiology of elite athletes.  Going in, I was under the impression we would debate the points, but that never really happened, mostly because I didn't think it was going to be cut short at 7 minutes.

You can listen to the podcast here.  Just click "Listen Now"  The interview portion starts at 9:00, as the section before is an interview with Chrissie Wellington (this provides some context for some of my comments in my first response).

A stunned reaction

I was, throughout the interview, stunned at what I was hearing.  And it's not as though I'm new to this particular debate - I've recently written two review articles on this topic with a colleague of mine (a geneticist, because unlike Anders Ericsson, I don't like the idea of commenting about a field that I'm not an expert in - he's a psychologist, but he was throwing physiology around with abandon, as you'll hear and read later).  These articles will be published in peer reviewed journals later this year, I'll let you know when.  There are also the two articles (PART I and PART II) that I wrote here on The Science of Sport last year, and then I presented on this at the UK Sports and Exercise Medicine conference in London last November.

I have also read the books - Bounce, Outliers, so in theory, I've heard it before.  But I was just absolutely stunned that Ericsson was saying some of the things he did - you can hear this in my reaction in the podcast as I start my response to both questions!  What he says is just ludicrous, empty and baseless, and I can only think he's misinformed, or has some other agenda to push.  Maybe he is writing a book...

Truth is, you don't even need research, you just need common sense and a tiny bit of experience with elite athletes in training groups.  For example, if any of you have ever run with a training group, you have seen and felt the reality of "individual responses" to training - you know that 1,000 hours of identical training will not produce an identical result in ten different people.  There are examples all over the place that show that practice is not sufficient for elite performance, and there are as many examples of athletes who have succeeded on far, far less than this (there are even cases in chess, where, dare I say it, performance is a little less complex because there's no risk of overtraining, injury, etc)

Also, Ericsson's theory that it is the training done during the adolescent years that matters is not only wrong (look how many talented young athletes fail at senior level despite accumulating far more hours than their peers by the age of 18, and how many endurance athletes only take up the sport in their 20s and become world class in a few years despite zero training when adolescents), it's also very irresponsible, because it compels parents, teachers and coaches to start training young athletes too soon and that's detrimental to the person (see Cote et al for review).

The statements - no scientific evidence showing that genes or physiology limit performance?

In his second response in the podcast, Ericsson makes the following statement in response to my argument that the scientific evidence suggests without doubt that elite athletes and champions are BORN AND MADE:
"I would argue here, and reading all the reviews, and we've had reviews where every scientist from the exercise physiology field and sports psychology.  And I find it kind of remarkable that Ross is making these claims because I've never seen them made in print in any peer-reviewed publication" - 13:55 in the podcast
He goes on to say the following:
"I have to say that I'd be very interested to see Ross finding any scientific studies that support the kind of claims that he was making at the beginning of the programme" - 15:01 in the podcast
Outside the scope of knowledge - don't tread where you shouldn't unless you have a guide

Before I continue, just have to mention that I have provided a list of peer reviewed publications as references at the end of this post - they are both review articles (Ericsson made the claim that he's read ALL the reviews - clearly he's missed these ones), and they are original research studies that show the importance of genetic factors and physiological variability to training.  Clearly, he's never read these either.  I'd excuse this on the basis that Anders Ericsson is a psychologist, so one would not expect him to have a firm grasp of sports science, performance,  physiology and the genetic literature, but the fact of the matter is that he's making claims in those fields, so therefore it's fair-game to challenge his knowledge and understanding of the literature and the sports science performance fields.

And I must just make this point - I don't for a second think we should create intellectual "silos" where you can ONLY comment on your field.  I think that would be foolish because it's the process of thinking, the scientific approach to a question that matters more than the actual content.  And I'd like to think that the biggest advances in our understanding often come from thinking outside the "constraints" of what we know, and by integrating research from different fields by different experts.

In other words, someone may be trained as a physiologist, but it's their application of the scientific approach, allied to some small physiological understanding, that may allow them to contribute to the field of biomechanics of barefoot running, for example.  Key to this are two things:  a)  you must be dilligent about doing your research, and b) find someone who IS an expert to assist.  That's why when in writing review articles on talent vs training and elite performance, I partnered with a geneticist (Malcolm Collins) who does understand the field at the depth that is required to put scientific statements out there.  Similarly, I'm now doing barefoot running research, where my interest is the physiology, but we have a team that includes an engineer and biomechanist, so that I don't have to tread where I'm not capable.

Responding to Ericsson - one example of "limited" physiological response to training

In any event, during the debate, I tried to respond to Ericsson, and there are four things that I think are essential to understand here:
  1.  It is true that genetic "proof" has yet to be provided.  But elite sporting performance is too complex, and genetic factors too varied to ever "prove" the link Ericsson seems to require.  Consider this:  height is a pretty straightforward characteristic, and it's known to be highly heritable (tall parents = tall children).  In fact, 80% of the variance in height is known to be genetic.  However, studies have found that it takes an astonishing 300,000 genetic variants to account for only 45% of this variance.  That's just height - how much more then would it take to explain something as complex as sports performance? 

    The reality is that the field of genetics is young, and with time, more evidence will emerge.  But there's a massive difference between something being "proven" (where I agree with Ericsson) and saying that it is absent (which is what he implies).  Genetic evidence is not absent - most physiological factors that are known to limit performance have been associated with genes (including injury risk, aerobic capacity, muscle fiber type), and others can be easily related to heritable factors (think height for basketball, limb proportion, bone mass etc).  When Ericsson suggests there is no evidence, it is because he is ignorant of the evidence.
  2.  Ericsson's own work disproves his theory - his studies have tried to explain performance level as a function of training, yet research he has been involved in shows that only a very small part of performance can be explained by practice.  Only 28% of the variance darts performance is explained by the number of hours practiced!  That's astonishingly low, and it means that time spent in practice is a very poor predictor for performance.  The question you should be asking is what accounts for the other 72%, and could some of it be innate?  It's definitely enough to throw out the deliberate practice, 10,000 hour theory, because Ericsson is clearly predicting that most (or all, in some of his articles) of performance is explained by training.
  3. You cannot prove that practice is necessary AND sufficient to produce champions or elite performers based on retrospective studies.  They're weak, because there are so many other ways to explain the findings.  For example, Ericsson's famous violin study showed that the expert performers did the most practice, and he concluded that the practice turned them into experts.  However, it's equally possible, in this study design anyway, that the children with the innate violin ability were encouraged by others and their own success to practice more.  Retrospective studies are poor ways to show that practice makes perfect.  You have to do prospective studies.
  4. Prospective studies have been done.  Most notably, Bouchard published a study in 2011 (reference below) in which he found that the response in VO2max (a measure of aerobic capacity and adaptation to training, and ultimately performance) of a large cross-section of the population to a standardized training programme was enormously varied.  Some individuals improved by less than 5%, others improve by 30%.  And here's the key point - it is possible, using genetic techniques, to identify which genetic polymorphisms (think of them as variants of genes) are responsible for this huge difference. 

    It turns out that Bouchard's work has provided some pretty important findings:
    • About 50% of an individual's starting VO2max and 50% of the "trainability" in VO2max is heritable
    • 21 Genetic polymorphisms have been associated with 50% of the training response to VO2max
    • If a person carries NINE OR FEWER of these genetic variants, then they are low responders and improve VO2max by only 200 ml/min.
    • If a person carries NINETEEN OR MORE of these variants, then they are high responders and improve VO2max by over 600 ml/min
In other words, genetic factors very clearly impact on what we start with, they impact on how we adapt to training, and therefore, by extension, they impact on where we get to.  Our physiology has a ceiling, and it is in part, genetically determined.  This is clear for VO2max, and it's clear for other factors that are known to affect performance.  Skeletal muscle, for example, is known to be BOTH heritable and trainable.  Running economy differs enormously between individuals as a function of factors such as height, limb proportions, muscle mass, and other factors that are known to be genetically determined.  And so unless you have the right skeletal structure, height, limb proportions, you cannot have the running economy required to run a 2:08 marathon.  It's physiology, limiting performance, and related to factors that we are born with.  To deny this is to say that the world is flat when you are staring out of a spaceship window at the globe.

Further, as one of you commented on Facebook yesterday, biomechanical factors such as the muscle's moment arm exert huge effects on performance, and so characteristics that we are born with determine the level of performance that we can attain.  I would point out the most obvious example of this is basketball, but there are countless others.

A pointless polarization of the debate

Ultimately, however, the idea that elite sporting performance can be explained by one factor is foolish.  That's why when Ericsson makes the claims he does, in the field of physiology, it's so absurd, and potentially damaging because people believe it at face value, and they implement sports systems and strategies that buy into this flawed concept.   It's quite clear, from what we observe in athletes, what we study in laboratories, what we know from geneticists, that there is a significant contribution of all kinds of factors to performance.  Physiology matters, but so does practice.  Psychological factors are crucial, but so too are financial and economic considerations.

The dominance of Kenyan runners, for example, will never be found to be due to ONE factor.  Those who are looking solely at genes are doomed to failure, but so are those who want to say that it's purely an altitude, diet, socio-economic, lifestyle, or incentive-driven phenomenon.  All these factors contribute, and the environment interacts with the genes to produce a champion.  I've said this before, but training should be defined as the realization of genetic potential.

Every single person improves as a result of training - some, as Bouchard has shown, improve by very little in a variable like aerobic capacity.  Perhaps they are better suited to skill-based sports.  Some improve enormously, and those who do are more suited to endurance sport.  Then there is injury - this is vital and completely overlooked.  We know that certain genes are associated with different performance characteristics, and there are genes that are associated with injury.  Some people will never even reach 10,000 hours because they are susceptible to injury at five hours per week of training and cannot do more - they'd need 40 years to get good enough if that's all it took.

So the point I'd like to conclude with, before I list some more points for Anders Ericsson to consider, is that we should not polarize the debate.  We should recognize that there are many paths to elite performance, and that a one-size or one-number fits all approach is foolish.  We should learn what we can from those who succeed, including that they are dedicated and practice a lot, which is obvious.  And we should learn why people fail.  And we should avoid generalizations and simplifications that help us sell books to motivate people.

Training is the realization of genetic potential - practically, that means that every single one of you reading this, discussing this, can improve through training.  That's the motivation. But will we all become Olympic caliber athletes in any sport we choose?  Keep dreaming.  The world is not flat, Prof Ericsson.  Please stop telling people it is...


By way of an "Appendix", here is a little more on Ericsson's views, because I don't want to take him out of context in a 7 minute radio interview...

Ericsson's first entry into this field was his work looking at skill acquisition in activities such as music - his seminal study of violinists showed that expert performers engaged in at least 10,000 hours of training whereas those violinists judged merely as "good" or "average" did about 8,000 and 5,000 hours respectively.

But then Ericsson moved beyond education and skill acquisition and began to tackle sport.  He wrote a review article in the New York Academy of Sciences Journal in 2009, in which he states the following:
"the distinctive characteristics of exceptional performers are the result of adaptations to extended and intense practice activities that selectively activate dormant genes that are contained within all healthy individuals’ DNA." - Ericsson et al, NYAS, 1172: 199-217, 2009
So in other words, he is now going to tackle genetics.  He is saying (and I want to be careful here about taking this out of context), that exceptional performers become exceptional because they practice, and this training activates dormant genes, and these genes are present in ALL healthy individuals' DNA - his word, my emphasis.

Right, so this is fine, if he sticks to "performance" in skill-based activities.  I would disagree with him - studies on chess show clearly that some people get good very quickly, others never improve to Master level no matter what they do.  The same is true of darts, tennis, golf, any activity.  But nevertheless, let's assume that he is referring to his study on musicians and things like mathematical ability.

But he doesn't stop there. He then tackles physiology, and writes the following in the same paper:
"From this evidence it would appear that VO2max/kg (aerobic capacity) would not be a good candidate for a factor that was constrained by heredity"
This comes from a section in the paper where Ericsson, a psychologist, tackles the PHYSIOLOGY of elite performance and comes to this incredible conclusion that there is no evidence that aerobic capacity is constrained by genetic factors.  If you read the study, you will discover that Ericsson arrives at this conclusion based on THREE studies - one review, and two other studies, one of which actually finds the opposite to what he concludes. 

I have explained above the recent work that shows clearly that genetic factors influence VO2max, and admittedly, this review precedes that series of studies.  But there were still others that had found a) huge inter-individual differences between people in response to the same training and b) accounted for large parts of VO2 as being heritable.

Ericsson's approach to the physiology side of this argument is simply not good enough when physiologists can cite dozens of physiological systems or factors that are known to affect performance, and when geneticists can show associations between these systems and our genes.

And yes, I agree that this area is not yet developed - it's so "young" a field that it will take time to understand the genetic complexity.  But even here, there's a difference between something being absent and something being proven.  Neither side will "prove" their argument, but I think it's pretty clear that evidence shows conclusively that BOTH genes and training make champions.

And finally, here are some references that Ericsson may have missed:

Duffy L, Baluch B. Dart performance as a function of facets of practice amongst professional and amateur men ana women players. Int J Sport Psychol. 2004;35:232-245.

Vaeyens R, Güllich A, Warr CR et al. Talent identification and promotion programmes of Olympic athletes. J Sports Sci. 2009;27:1367-80.

Elferink-Gemser MT, Jordet G, Coelho-E-Silva MJ et al. The marvels of elite sports: how to get there? Br J Sports Med. 2011;45:683-4.

Phillips E, Davids K, Renshaw I et al. Expert performance in sport and the dynamics of talent development. Sports Med. 2010;40:271-83.

Huijgen BC, Elferink-Gemser MT, Post WJ et al. Soccer skill development in professionals. Int J Sports Med. 2009;30:585-91.

Gobet F, Campitelli G. The role of domain-specific practice, handedness, and starting age in chess. Dev Psychol. 2007;43:159-72.

Gibbons T, Hill R, McConnell, A. et al. The path to excellence: A comprehensive view of development of U.S. Olympians who competed from 1984-1998 United States Olympic Committee. 2002.

Baker J, Côté J, Deakin J. Expertise in Ultra-Endurance Triathletes Early Sport Involvement, Training Structure, and the Theory of Deliberate Practice. J Appl Sport Psychol. 2005;17:64-78.

Oldenziel K, Gagne F. Factors affecting the rate of athlete development from novice to senior elite: How applicable is the 10-year rule. Athens 2004: Pre-olympic Congress Sport Science Through the Ages: Challenges in the New Millennium. Athens. 2004.

Hodges NJ, Starkes JL. Wrestling with the nature of expertise: A sport specific test of Ericsson, Krampe and Tesch-Römer’s (1993) theory of “deliberate practice”. Int J Sport Psychol. 1996;27:400-24.

Helsen WF, Starkes JL, Hodges NJ. Team sports and the theory of deliberate practice. J Sport Exerc Psychol. 1998;20:12-34.

Bullock N, Gulbin JP, Martin DT et al. Talent identification and deliberate programming in skeleton: ice novice to Winter Olympian in 14 months. J Sports Sci. 2009;27:397-404.

Roescher CR, Elferink-Gemser MT, Huijgen BC et al. Soccer endurance development in professionals. Int J Sports Med. 2010;31:174-9.

Vaeyens R, Lenoir M, Williams AM et al. Talent identification and development programmes in sport : current models and future directions. Sports Med. 2008;38:703-14.

Tucker R, Collins M. Athletic performance and risk of injury - Can genes explain all? Dialog Cardiovasc Med. In Press.

Collins M, Raleigh SM. Genetic risk factors for musculoskeletal soft tissue injuries. Med Sport Sci. 2009;54:136-49.