Examining Injury Risk And Pain Perception In Runners Using Minimalist Footwear

A new study was published in the British Journal of Sports Medicine looking at injury risk in runners using minimalist footwear. I saw one podiatrist exclaim online that this study represented the “end of the minimalist shoe fad”.  I find it hard to understand why there is such a push from healthcare professionals to label light, flexible shoes a fad. A very sound argument can be made for why minimalist shoes are better than traditional running shoes. It may take some time for this to be shown in research, for reasons I will touch on later in this post, but first let us look at the somewhat misleading abstract of this present study:

Examining injury risk and pain perception in runners using minimalist footwear
Br J Sports Med; Published Online First 19 December 2013

Background: This study examines the effect of progressive increases in footwear minimalism on injury incidence and pain perception in recreational runners.

Methods: One hundred and three runners with neutral or mild pronation were randomly assigned a neutral (Nike Pegasus 28), partial minimalist (Nike Free 3.0 V2) or full minimalist shoe (Vibram 5-Finger Bikila). Runners underwent baseline testing to record training and injury history, as well as selected anthropometric measurements, before starting a 12-week training programme in preparation for a 10 km event. Outcome measures included number of injury events, Foot and Ankle Disability (FADI) scores and visual analogue scale pain rating scales for regional and overall pain with running.

Results: 99 runners were included in final analysis with 23 injuries reported; the neutral shoe reporting the fewest injuries (4) and the partial minimalist shoe (12) the most. The partial minimalist shoe reported a significantly higher rate of injury incidence throughout the 12-week period. Runners in the full minimalist group reported greater shin and calf pain.

Conclusions: Running in minimalist footwear appears to increase the likelihood of experiencing an injury, with full minimalist designs specifically increasing pain at the shin and calf. Clinicians should exercise caution when recommending minimalist footwear to runners otherwise new to this footwear category who are preparing for a 10 km event.

The conclusion states that “minimalist footwear appears to increase the likelihood of experiencing an injury”. Looking a little closer we see this is not the case. The study actually had two minimalist shoe groups that they labeled partial and full. The partial minimalist group ran in the Nike Free 3.0. The full minimalist group ran in Vibram 5-Finger Bikilas.

It was the partial minimalist group (Nike Free 3.0) that had the significantly higher rate of injury. There was not a significant difference in the rate of injury between the neutral shoe group and the full minimalist group. So the conclusion should more accurately state that “running in partial minimalist footwear increased the rate of injury, but running in full minimalist shoes did not increase the rate of injury”.

To be even more accurate, the study should say that runners using the Nike Free 3.0 had a higher rate of injury than runners in the Nike Pegasus. You can not declare that partial minimalist shoes (plural) increase the risk of injury when only studying one model. That would be like saying driving luxury cars increases the risk of your engine catching on fire, but then only studying people driving Jaguars XF’s.

The Nike Free has some minimalist features, like a 4mm drop and a flexible sole. But it also has cushioning and some arch support similar to traditional neutral shoes. If minimalist shoes really caused injuries, wouldn’t it make sense that the most minimalist shoe in the study would cause the most injuries? That’s not what the researchers found.

The runners using the Vibrams, which are more of a true minimalist shoe than the Nike Frees, did not have significantly more injuries. The authors could have just as likely concluded that running in minimalist shoes does not increase the likelihood of injury, but they didn’t. The reason they didn’t may have something to do with the Vibram group reporting significantly greater calf and shin pain after the 12 weeks.

Anyone who has transitioned from bulky traditional running shoes to minimalist shoes knows that it takes time to build up calf strength and flexibility. Less supportive, zero-drop shoes require you to use your calf muscles to a greater extent than traditional raised-heel shoes. The study did not find any difference between the groups for pain level in other areas of the body they looked at (foot/ankle, low back, pelvis/groin, knee).

There is certainly some calf soreness that comes a long with transitioning to less cushioned and supportive shoes, just as there is soreness anytime you exercise a muscle group that hasn’t been used in a while. I consider this one of the benefits of running in minimalist shoes, the transfer of stress from the knee to the calf muscles and Achilles tendon. 

The abstract didn’t report what types of shoes the runners were using prior to taking part in the study, but my guess is that most were in traditional running shoes. Cushioned, raised-heel shoes with support features make up the overwhelming majority of the running shoe market. It has been shown before that wearing traditional shoes changes the way people run. Runners who are adapted to using traditional shoes need time, often several months or longer, to condition themselves to run without the cushioned heels and support. Sometimes gait training is necessary to undo the motor patterns learned from wearing traditional shoes. The study only allowed the runners one week to adjust to the shoes they were given. I am willing to bet the outcome of this study would have looked very different with a group of runners already running in minimalist shoes. 

To use another car analogy, imagine a study was done where researchers switched the positions of the gas and brake pedal and then studied who had more accidents, the drivers in the traditional cars or drivers in cars with the pedals switched. The study would probably find that driving with the gas pedal on the left caused more accidents. But it would be wrong to conclude that having the gas pedal on the left is dangerous. It is only dangerous because people are accustomed to having the accelerator on the right. 

Same goes for shoes. If people didn’t start running in raised-heel, cushioned shoes then running in minimalist shoes would never be an issue. Remember, there is no scientific reason why traditional shoes are designed the way that they are. Only tradition. But because traditional shoes are so widely used, the effects  caused from running in them over time need to be taken into account when conducting a study like this. To examine what the true difference in injury rates is, we would need to compare runners who have grown up using traditional shoes to runners who have grown up wearing minimalist shoes. Since minimalist shoes have only gained popularity in the last several years (and still only make up only a small fraction of the shoes on the market) it may be a while before large studies like this are possible.  

Comments

  1. Freyja says

    I totally agree with you. I don’t think this was a scientific study, only a biased one! I’m a convert, although I’m still working on getting my traditional shoes out the door. Almost every person I tell about my intentions looks as if I’m saying that the earth is flat. But by the time it’s summer I’d like to see myself running fulltime in minimalist shoes and occassionally barefoot. I’m gonna start by trying to fix my flat feet (thanks for your website on that subject!) and then slowly make the switch to minimalist.

    • James Speck says

      Hi Freyja,

      Good luck with your transition! Working on strengthening my arches is what ultimately led me to toss the stability shoes. I completely understand what you are saying about the looks people give you when you talk about going with less supportive shoes! The idea that we need clunky, rigid shoes has been so entrenched in our culture. I get bothered seeing barefoot activity/minimalism being continuously talked about as dangerous or a passing fad because this is totally backwards. It’s traditional shoes that people should really be concerned about.

  2. Kris, PT says

    I have yet to pull the entire article but will do so shortly and perhaps reply again. Thank you for posting, I look forward to reading it with a critical eye.

    After years of treating injured runners as a doctor of physical therapy and runner myself, I must say that I have seen some serious injuries during the transition from stable shoes to less stable shoes. Femoral fracture, serious compartment syndrome (considering surgery), metatarsal fracture, achilles tendonopathy, mid-foot ligament instability (lifelong now likely), among others. I am speaking from clinical experience and making observations.

    On the flip side, I have found it helpful for the right patient as an adjunct (not the only/primary shoe) notably for knee pain, hip pain and back pain. But this is a tricky process, so proceed with caution and LISTEN to your body as you should during all forms of exercise, notably when changing shoes, technique, running, surface, or training regimen.

    For a healthy/uninjured runner looking to supplement their training, I would be much less likely to recommend a partial minimalist shoe if running on hard surfaces. If the person is running on grass/dirt, I would be ok with CONSIDERING a more pure minimalist shoe.

    Buyer beware, run smart, have fun.

    • Kris, PT says

      Correction of above. If you are uninjured, I would be MORE likely to consider a less stable (partial minimalist) shoe although caution would still be warranted.

  3. James Speck says

    Kris,

    I appreciate your input. Your experience highlights why I think there has been a sort of push back against minimalist shoes. If anything, this study reinforces that there needs to be a slow transition to minimalist footwear IF you have been running in traditional shoes. It may take 12 weeks, it may take 12 months.

    My contention is that there would not be a need for a transition if modern supportive footwear was never introduced. Kids need barefoot activity to help their feet develop structurally and functionally. Rigid or supportive footwear can be detrimental to their growth and development. But because traditional supportive shoes are so widespread in our culture, kids get introduced to them early on. Then we wonder why people have trouble adjusting to flat, flexible shoes as adults!

    This is a problem CREATED by modern footwear. Health care professionals play a role in this with the often repeated recommendation of supportive footwear and alarmist stance on less structured shoes. There’s no evidence that conventional running shoe design prevents injuries, and there’s several plausible ways they may in fact be harmful.

    If the issue is running on hard surfaces, first let’s recognize that the cushioning in neutral shoes is much softer than most natural surfaces. I can see this as a reason to add FIRM midsole cushioning to shoes, but this can be done without adding the other features (raised heel, arch support) found in traditional shoes.

  4. Kris, PT says

    Tom and James,

    How sure are either of you that modern footwear has CREATED anything from childhood to adulthood? Everyone in my business has read “born to run”, so the anecdotes ARE intriguing. However, do you have any empirical evidence of a reasonable population of people in a modern environment, and modern lifestyle, where it was proven that modern shoes caused anything? If it is speculation, we should call a duck a duck. Speculation and hypothesis forming is the backbone of modern science. But a duck should never be called a goose.

    Kris

    • Tom says

      hi, Kris, sometimes pictures say more than 1000 words, so the answar to your question “how sure are either of you that modern footwear has Created anything from childhood to adulthood?” you gonna see in my opignon in picture 2 and 3 in this blogpost of mine: http://swiss-functional-training.ch/?p=999 it is no ‘empirical evidence’ but for me its enough. greetings, tom

  5. James Speck says

    Kris,

    There is rather clear evidence that shoes affect the structure of the foot and biomechanics. Wegener 2011 is a systematic review on the effect shoes have on children during walking and running. D’Aout 2009 compared foot shape and function in habitually shod and barefoot populations. One study presented last year found cushioned heeled running shoes caused adolescents to heel strike.

    Then there are the many recent studies showing kinematic differences between barefoot/minimalist runners and runners in traditional shoes. McCarthy 2013 for instance showed that 12 weeks of running in Vibrams caused runners to adopt a more forefoot strike and “barefoot” kinematics. For me, it’s almost impossible to over stride or even land on my heels unless I’m wearing cushioned shoes.

    Is this enough to conclude that maximalist shoes cause injuries? No, but as I mentioned in the article it can take a while for these questions to be answered. Cushioned, supportive shoes make up approximately 90% of the running shoe market today. Yet there are no studies showing any benefit of maximalist shoes for either reducing injuries or improving performance. The addition of cushioning and support features to shoes was all based on speculation, and the practice has continued, with all the structural and functional consequences, despite this lack of evidence.

  6. Jane Dew says

    I totally agree that this study is flawed. What people don’t seem to appreciate with minimalist shoes is that they need to work on adapting their running style back to that which nature intended. It’s not enough just to slap on some five fingers and head out for a 10 miler! Injury will almost certainly follow! I did a running technique course where we were video-do in our chunky supportive trainers, then we were given some drills to practise, then re-videoed barefoot. One of the guys on the course, when video-ed barefoot ran on the forefoot with a high heel lift, good posture etc. He then put on his five fingers and immediately reverted to a heel striking walk/run hybrid! So even a minimalist shoe adjusts the proprioception of your foot. So if you’re going to make the switch it takes time and discipline but since I have done it I no longer get traditional runners injuries and my race times have improved!

  7. Meredith says

    My background is I have been a shoe saleswoman for three years I currently work for ASICS, but I have worked for Nordstrom selling shoes and a Boutique. I have seen 1,000+ of feet. My biggest observation is most people are wearing the wrong size.

    I will use my self as an example, I have wide feet with a shallow arch. My foot length measures at 7.5 but my arch in my left foot is a size 8.5 and in my left is a size 9. I am prone to over-pronation. A bad shoes sales person would tell me I have flat feet and put me in the most structured shoe and probably not have properly measured the arch of my feet. After working with a trainer I discover I have tight hip flexers which I believe can cause over-pronation. My solution is change up my footwear I have shoes with the drop heel and traditional running shoes.

    Most people women especially do not get properly fitted. People no longer walk places so this is little awareness of how their feet work. I am not completely sold on minimalist shoes in the sense I don’t think they are a magic solution some of the avid users claim they are to be. I do think that they have a place. I think is is human nature to want quick solution to bad lifestyles, wear this magic insert and it will solve 40 hours of sitting all day. Also some shoes salesman can go a bit over their pay grade, after 5 minutes they know you chronically over pronate and tell them they have to wear a structured shoe and then they don’t even show the person there.options. My job as a shoe sales woman is to properly fit you tell you what I know you make the choice.

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