Have a look at the video:

The video is interesting in that it compares a guy running both barefoot and in the Super J33 shoes on a lab trackway. Asics describes the shoe as a “natural running shoe for overpronators” and makes claims about 45% of runners being overpronators and how overpronating can put more stress on muscles and ligaments. When I see claims like this about overpronation, my immediate reaction is to reference this excellent post by podiatrist Ian Griffiths, who writes:

“…the term ‘overpronation’ is neither accurate, descriptive nor meaningful, and should therefore be erased from modern day usage in both the lay and the medical communities.”

I agree.

I guess this shoe allows you to run naturally minus that nasty overpronation, which really needs to be corrected so that you run a bit less naturally.

Oh, and the shoe also apparently changes your natural foot strike as well (assuming by natural running they mean running like you do when you’re barefoot):

In actuality, the video is pretty cool in that it shows how things can in fact change when you go from barefoot to shod, and that shoes do influence gait. It does also seem like the runner pronates less when in the shoe (hard to tell without using bone pins since estimates of eversion based on external markers are unreliable), but I’d ask if that’s necessarily a good thing?

I’m not opposed to the idea of a stabillity shoe, and I do think that reducing pronation can be a positive thing in managing certain injuries (particularly if the shoe is causing the excessive pronation). My guess is that I’ll like running in the Super J33. But as Ian Griffiths always likes to point out, overpronation is not a diagnosis. It is not something that must be controlled at all costs. Sometimes controlling how the body wants to move can be just as problematic as trying to make it move the way we think it should. I’d hoped we’d moved beyond this with the science that has come out over the past several years, but apparently not. The battle rages on…

Several commenters on these posts have indicated that maybe it’s time to move away from stability shoes and give neutral shoes a try. I thought I’d share a few thoughts on this as I don’t necessarily think this is the way to approach things when it comes to running footwear.

Do Pronation-Control Categories Mean Anything?

One of the biggest problems with making neutral a goal is that it assumes that “stability” and “neutral” are actual categories with well defined limits and precise meaning. I don’t believe this to be the case. As far as I’m aware, and correct me if I’m wrong, there are not hard criteria a shoe must meet in order to be classified as a stability or a neutral shoe. It seems that a medial post or some other type of pronation control “technology” is all that’s needed to make a shoe fall into the stability category.

Having run in a lot of shoes over the past few years (I’ve lost count, but wouldn’t be surprised if it’s over 75 now), I’ve rarely found the stability/neutral categorizations to be very helpful – I run in both with little issue. In fact, I’ve run recently in both the Saucony Guide 5 (stability) and Ride 5 (neutral) and I’ll be darned if I could tell you which is which if I put them on with my eyes closed. I’ve even run in neutral shoes with firm soles that almost feel too stable (e.g., many adidas shoes such as the adios 2 and Feather 2).

I think the reality is that there’s way more to making a shoe “stable” than just throwing a medial post on it (and it’s even debatable how effective posts are – gait expert and PT Jay Dicharry once told me that it’s one of the least effective methods of improving shoe stability since the foot pronates most after the post has left the ground during stance). If we define stability as a shoe that minimizes inward roll of the foot (what we runners colloquially refer to as pronation), I personally find that stability is mainly a function of cushioning firmness (firmer = more stable), cushioning amount (thinner sole = more stable), and shoe width (narrow shoes make me feel less stable). I also find torsional (twisting) flexibility to be important – stiff shoes with thick soles feel very slappy to me and I suspect they increase pronation velocity.

Another problem with making “neutral” a goal to strive for is that I don’t really know what neutral as a category means (or that neutral has any meaning for the foot either – read this post by Ian Griffiths for more on this). Some neutral shoes are so soft that they cave medially and cause the foot to pronate way more than it ever would when barefoot (like my wife’s foot in the Nike Free 5.0 at the top of this page; see also this post which hones in on this aspect of neutral shoes). Some are so firm that they feel more stable than a lot of “stability” shoes. The New Balance MT110 is a neutral trail shoe, but because the sole in my pair is so slanted from lateral to medial I can feel it forcing my foot to evert just standing in them – they gave me a case of posterior tibial tendinitis after a long trail run.

Look at the photos below for an example of how three “neutral” shoes can behave differently on the same person – this demonstrates well the lack of a standard response within a category:

adidas adizero Adios 1 (right) with high and narrow sole rolls over medially. Nike Lunar Racer (middle) with wide sole is more stable, and Asics Piranha (left) with lower profile has less tendency to tilt.

Here’s the same person showing foot movement barefoot and in stability and neutral shoes – the neutral shoe appears to cause a lot more inward roll than when he is barefoot:

Does Shoe Motion Correlate With Foot Motion?

An entirely separate issue is the fact that how a shoe moves may have little correlation with how the foot moves inside the shoe. For example, here is the Abstract of a classic 2000 paper by Alex Stacoff that tried to differentiate shoe movement from the actual movement of the foot inside the shoe by inserting pins into the foot and leg bones:

Abstract

Barefoot running kinematics has been described to vary considerably from shod running. However, previous investigations were typically based on externally mounted shoe and/or skin markers, which have been shown to overestimate skeletal movements. Thus, the purpose of this study was to compare calcaneal and tibial movements of barefoot versus shod running using skeletal markers. Intracortical bone pins with reflective marker triads were inserted under standard local anesthetic into the calcaneus and tibia of five healthy male subjects. The subjects ran barefoot, with a normal shoe, with three shoe soles and two orthotic modifications. The three-dimensional tibiocalcaneal rotations were determined using a joint coordinate system approach. Test variables were defined for eversion and tibial rotation. The results showed that the differences in bone movements between barefoot and shod running were small and unsystematic (mean effects being less than 2°) compared with the differences between the subjects (up to 10°). However, differences may occur during midstance when extreme shoe modifications (i.e. posterior orthosis) are used. It is concluded that calcaneal and tibial movement patterns do not differ substantially between barefoot and shod running, and that the effects of these interventions are subject specific. The result of this in vivo study contrasts with previous investigations using skin and shoe mounted markers and suggests that these discrepancies may be the result of the overestimation with externally mounted markers.

The point made by this study is that the movement we see when looking at the shoe from behind may not actually reveal much about how the foot inside the shoe is moving. In other words, a stability shoe may look like it keeps the foot in a more “neutral” position, but the foot may simply be pronating inside the shoe just as much as it would when barefoot.

The Origin of Pronation Control

Another thing to consider is why pronation control devices in shoes were developed in the first place – was the original goal to correct a problem with our feet? I’m not so sure…

The footwear trend in the 1970’s was to add additional cushioning to shoes, particularly under the heel. The reason for this was that Achilles tendon problems were among the most commonly reported injuries in the early 70’s, and lifting the heel was thought to reduce strain on the Achilles. I have also heard that adding cushion was also done to accommodate a changing demographic of runners (new to the sport, perhaps not as fit) – read this book excerpt for more on running injuries/shoes in the 1970’s. However, adding cushion seemed to have some side effects. The late 1970’s saw a decrease in Achilles problems, but a dramatic increase in knee injuries. The latter were thought to be linked to reduced rearfoot control due to the cushioning added to shoes. Excessive rearfoot movement was linked to excessive internal tibial rotation (i.e., the shin twisting inward), which was in turn thought to contribute to the development of problems at the knee. This gave rise to the addition of pronation control elements in an effort to control the rearfoot and save the knee (knee injuries are still by far the most common running injury).

Benno Nigg, one of the scientists who was heavily involved with the study of shoes during this time period (and is still  a major researcher in the shoe world today) has since stated that attempting to control foot motion was a mistake – here’s a snippet from a 2010 Runner’s World article featuring Nigg:

“…In the early 1980s, Nigg was working as a consultant for Nike on its line of tennis shoes. While there, he offered input on the need to add more structure to Air models because the much-lauded Air units created even more instability than traditional foam. “I pushed the cushioning trend as much as anyone,” the broad-shouldered Nigg says in his Swiss accent. “And I take the blame for pronation devices as well.””

So the reality is that pronation control technology seems to have appeared to correct problems caused by the addition of cushion and heel lifts to shoes. It was a new element added to shoes to correct for problems created by another new element. (If you are interested in footwear history from the 1970’s, I highly recommend that you read The Running Shoe Book from 1980 by Peter Cavanagh).

In fact, I don’t get the feeling that the appearance of pronation control had anything to do with correcting an inherent problem with our feet (it was correcting a problem with our shoes!). Unfortunately, it has morphed into that for many runners today who feel that they “need” stability because they are an “overpronator” – in this sense overpronation has come to be treated almost as a pathological condition that needs correction lest you want to endure certain pain and suffering.

How Do You Find the Right Shoe?

What can we make of all of this, and how should runners find the right shoe?

I prefer to think of shoes in much the same way I look at runners – each is an individual with its own properties. I’m not at all a fan of footwear categories because there is no defining set of criteria that can be applied to each category, and no standardization as to just how stable a given shoe is. In a similar manner, I don’t like using “minimalist” to define a specific category as there is such a huge amount of variation in what different people would put into it. Is the Saucony Kinvara minimalist? How about the Altra Instinct? Thus, I don’t find the categories “stability” and “neutral” to be all that informative and basically just ignore them now when choosing shoes for myself.

My general feeling is that unless an individual runner has a specific pathology that has been linked to increased injury risk, they should aim to find a shoe that allows their feet to move as they want to move. Don’t attempt to control foot movement, and don’t wear something that is going to cause the foot to move even more than it would on its own. I do think video analysis can help with this to a degree, but keep in mind that we typically only see how much the shoe moves – it’s much harder to discern how much the foot is moving inside the shoe.

Don’t focus too much on categories, focus more on how individual shoes feel – comfort is good, and specifically comfort while running in a shoe, not while standing in it in a store. Benno Nigg, the scientist mentioned above, stated in an article by Amby Burfoot that “Comfort is not easy to define, but it’s ‘probably the most important variable’ for sport-shoe selection.” I would agree with him – I can usually tell after a single run whether a shoe is going to work for me, and it mainly has to do with knowing how a lot of different shoes feel on my feet. A shoe that feels comfortable on the very first run is generally one that stays in my rotation for the long term. I would also agree that comfort is hard to define, but for me I think it’s mainly just how good a shoe is at letting my body do its thing without getting in the way – a comfortable shoe is one that I barely even notice when I run.

The challenge is helping runners who aren’t shoe reviewers with access to large numbers of shoes figure out their own comfort zone – my feeling is that’s where the human factor comes in. Rely on your shoe-geek friends, knowledgeable and open minded specialty store clerks, and others with extensive shoe and running experience to help you out. One day I hope science will have better answers for us on how best to fit shoes, but I don’t think we’re there yet, and until then it remains more an art and a personal journey. It’s a journey that need not have neutral as its end goal.

One study that made a big impact on my thinking was published as part of a conference proceedings back in 2003. Titled “Do Pronators Pronate?” and authored by Stefanyshyn et al. from the University of Calgary, the study examined whether runner’s beliefs about which pronation category they belong to actually matched with how much their feet everted when measured in a laboratory (note, eversion is one component of the complex movement we call pronation and can be though of simply as the inward roll of the foot after contact).

In the study, the authors examined a total of 83 runners (42 males, 41 females) who self-classified themselves as either a “pronator,” a “normal” runner, or a “supinator” (self classification most likely resulting from being told in a shoe shop or through observation of their arch height). Forty one subjects classified themselves as pronators, 40 classified themselves as normal, and 2 classified themselves as supinators.

The researchers attached markers to the legs and feet of the runners and had them run five trials barefoot and five in a neutral shoe. Runners were filmed in slow motion as they ran across a force platform – this allowed for a detailed quantification of foot eversion.

For the barefoot condition, they classified individuals with a change in eversion (i.e., inward foot roll) of >15 degrees as pronators. For the shod condition, the pronator category cutoff was a change in eversion of > 16.5 degrees.

Here’s where things get interesting. The results showed that for the 41 subjects who called themselves “pronators,” only 5 fell into the “pronator” category in both the shod and barefoot conditions (12%!), and nearly 70% did not exhibit high eversion in either the barefoot or shod conditions. In other words, 70% of the runners who considered themselves to be pronators were actually well within the normal range based on the criteria established by the researchers!

Similar to the above, “normal” pronators were also pretty lousy at their self-classification. Eighteen of the 40 self-classified “normal” runners exhibited a level of eversion that exceeded the “pronator” cutoff – that’s nearly 50% of normal runners who were actually pronators based on the classification criteria.

The authors suggest that runners may define their pronation category based upon observation of their arch height, but found no significant differences between loaded arch height in the self selected “pronator” vs. “normal” groupings (the only significant arch height difference was a lower unloaded arch in male pronators compared to normal males). They also found no correlation between arch height and amount of eversion, indicating that arch height is not a valid indicator of how much a runner pronates (so much for the wet test! – for more on arch height, read this post).

Based on these results, the authors concluded the following:

“The above results lead to the following conclusions: Barefoot eversion, shod eversion and the perception of pronation are variables that do not describe the same phenomenon. People who consider themselves to be pronators may not be pronators. People who consider themselves to be normal may be pronators.”

Does not instill confidence that we know ourselves as well as we think we do, does it!

So, just because somebody told you that you are an overpronator does not mean that you actually are, and just because you have flat feet does not mean that you necessarily pronate excessively (maybe you can skip the motion control…).

Even if you are an overpronator, unless it’s severe, it may not matter all that much. Dr. Benno Nigg, who was one of the co-authors of this study, states in his recent book, Biomechanics of Sports Shoes, that:

“Pronation and supination have long been the “danger variables” hanging over the sport shoe community, but their time as the most important aspects of sport shoe construction is over. Pronation is a natural movement of the foot, and “excessive pronation” is a very rare phenomenon. Shoe developers, shoe stores, and medical centres should not be too concerned about “pronation and supination.”

In his book Nigg also says that based on his extensive research into the topic, and his knowledge of the relevant literature: “overpronation, as it occurs in typical runners, is not a critical predisposition for injuries.”

(Incidentally, if you don’t know who Benno Nigg is, he’s a highly respected footwear expert and was one of the pioneers of the development of stability shoes in the early 1980’s. He has since changed his mind, and was quoted in Runner’s World saying the following: “I pushed the cushioning trend as much as anyone…And I take the blame for pronation devices as well.”)

The above information contributes to why I believe that the pronation control model of shoe fitting needs to disappear – pronation can still be considered on an individual level when problems arise, but it should not be a primary criterion by which shoes are suggested to people in a shoe shop.

Stay tuned, as I plan to follow up shortly with a summary of a more recent study that provides similar results.

To read the Stefanyshyn paper click here.

Question:

Answer: Because someone at a shoe store told you that you need them, and they were told that you need them by a shoe company rep.

The above Q&A basically describes my feelings on the topic of overpronation. You might think that you wear such shoes because you need support for your “excessive” foot movement to prevent injury, but the reality is there is scant evidence at best that these shoes accomplish this goal, or that excessive pronation is even strongly linked to increased injury risk.

Unfortunately, the pronation control paradigm has come to dominate the world of shoe fitting, and judging by the number of people asking for shoe advice on online forums who start by claiming they are an “overpronator,” it’s not a topic that seems to be dying off as rapidly as it should.

The reality is that pronation is completely normal. If you walk in a shoe store and their sole basis for choosing a shoe for you is how much your pronate and what your arch looks like, turn around and walk out the door. You’re probably just as well-off choosing a shoe at random from an on-line store. The science simply does not support this protocol (I wrote an entire chapter in my book explaining why), and in fact may contraindicate this practice. Given this, I was pleased to see a post come across my blogroll by sports podiatrist Ian Griffiths.

The post, published on the Kinetic Revolution website, describes why Griffiths thinks that “the term “overpronation” is neither accurate, descriptive nor meaningful, and should therefore be erased from modern day usage in both the lay and the medical communities.” Griffiths covers a lot of ground in his article, pointing out such interesting tidbits as the fact that with regard to pronation:

Across many studies, all of the data collected from pain free and injury free subjects and athletes shows that very few individuals actually meet the historical definition of ‘normal’.

One study examined 120 healthy individuals both non weight bearing and weight bearing. Not one subject conformed to the historical criteria of a ‘normal’ foot. Further searching through the literature shows that the majority of data collected from sampled populations suggests that the normal (average) foot position at rest is actually mildly to moderately pronated, as opposed to ‘neutral’.

Regarding injury risk due to “overpronation,” Griffiths has this to say:

It is a commonly held belief that pronation will increase the risk of lower extremity injury.  However (perhaps surprisingly) this is not particularly well supported by the literature, with very few studies which actually show pronation increases injury risk.  Instead, there are numerous pieces of work which have shown there is no association with foot type and injury and some research exists which even suggests that a pronated foot type is actually protective against injury.

And I love and fully agree with the conclusion regarding what to do with the term “overpronation”:

Hopefully it is now clear that this is a term which contributes nothing to our understanding – it is not definable, not reliable or valid, not diagnostic, its relationship to injury is not fully understood, and it does not dictate what the most appropriate management plan may be.  It should not be replaced, it should be removed.

Griffiths feels that pronation is simply one factor to consider when dealing with an injured patient, and this is in line with my view as well. It’s one factor among many that could contribute to any given injury, and it has been given a primacy in the footwear world that it does not deserve. It would be like deciding all of a sudden that we should assign shoes to runners based on their amount of hip adduction and internal rotation because excessive amounts have been linked to increased patellofemoral pain syndrome risk – at least in this case there would be some science supporting the practice.

Anyway, I highly recommend heading over to read Griffiths full post at the Kinetic Revolution website. Hopefully the article will help to free you or your running friends and loved ones from the shackles of the pronation-control paradigm!