Recent research released late Feb. 2013 implies that there’s a good chance transitioning to Vibram FiveFingers may cause injury—specifically, bone injury.

The study was titled “Foot Bone Marrow Edema after 10-week Transition to Minimalist Running Shoes,” and the abstract can be found below. In brief, the study did the following:

  • Looked at 36 experienced, recreational runners, divided them into two groups, kept 17 running in their traditional shoes for the 10 week study period, and had the other 19 transition to running in Vibram FiveFingers over the 10 week period.
  • They used MRI scans before and after the 10 week running period to look for “bone marrow edema,” which is an indication of injury/inflammation as fluid builds up inside the bone.
  • The experimental group undergoing transition to FiveFingers running followed “[A] plan based on one offered at the time of the study (early 2011) on Vibram’s website. In the first week, they did one short run (1-2 miles) in Vibrams. During the next two weeks, they added another short run in Vibrams each week; that is, by the third week they were to do three runs of at least 1 mile in Vibrams. After the third week, they were told to increase the amount they ran in Vibrams as felt comfortable, with the goal of replacing one short run a week in conventional shoes for a short run in Vibrams.” [Details per RW]

The study found that slightly more than 50% of those transitioning to running in FiveFingers showed increases in bone marrow edema in at least one bone at the end of the 10 week period.

A cursory interpretation of the study would be that you’ve got a 50% chance of injuring the bones in your feet on transitioning to toe shoes like FiveFingers. As you might expect, the research is making waves in the minimalist/”barefoot running shoes” community.

What would a more nuanced take on the study be? I wanted to know, so I reached out to a few of the usual suspects—runners who have transitioned to minimalist/barefoot shoes including Vibrams and have personal experience around the subject.

What follows (after the jump!) are their thoughtful responses to this study. Read on!

Round the horn on responses to the study

I reached out to take the pulse of a few runners whose experience and opinions around running minimalist or “barefoot” I respect. A few are regulars here on BirthdayShoes — Tim Kelley, Greg Woods, and Rob Youngren — and I also had Tuck of Yelling Stop and Barefoot Ted’s barefoot/minimalist running forum fame weigh in, too.

Here’s what they all had to say!

Rob — “Extreme motivation needs to be tempered with extreme patience!”

I’ve actually just been reading through the many comments over at the Runner’s World write-up on this study and my thoughts closely match what Mathew Wallden said:

This is a great study – well put together and interesting results. The key is surely to get the right balance.

In essence what it shows is that there is a training stimulus to the bone if you wear VFF’s, or no training stimulus to the bone if you wear normal running shoes (having already been wearing them for years).

If that training stimulus is too great, the tissue will break down. If the training stimulus is correct, the bone will strengthen. It is much the same as lifting weights – we all know that this also stresses muscle (and bone for that matter).

If I were to ask you to lift a load you have been lifting already – and have been doing so for years, when I reassess your muscle at the end of 10 weeks, I would see no change, no training effect, and no inflammatory markers on MRI. If I asked you to increase that load (and we know BF running increases loads to the 2nd Metatarsal head as it creates a more efficient running action) then after 10 weeks we would see a) inflammatory markers and b) gains in muscle strength. However, if I asked you to either lift extreme loads, or take no rest days, I would expect to see an injured muscle with a lot of inflammatory markers… This is simply what is going on here.

Anyone who is in touch with their body will not have these problems and will only strengthen as a result. Anyone with a no-pain, no-gain mentality is at high-risk of injury. Which category do you fall into?

I’ve honestly seen enough injury testimonies on from VFFs and other extreme minimalist footwear over the last couple of years that I firmly believe this study is spot on.

We can’t ignore the fact that people are indeed getting injured wearing this class of footwear.

Now what I can’t comment on is, overall, is this injury rate out of the norm compared to the injury rate of folks wearing more traditional footwear. I could be convinced either way. Running is extremely tough on your body: joints, muscle tissue, ligaments, bones etc…, especially for those who are relatively new to the sport. It takes A LOT of time on the feet for your body to adapt which is why you often see so many traditional running shoe folks suffer from shin splints or plantar fasciitis and other ailments. So perhaps what we’re seeing is just growing pains but in a different way; the dreaded TOFPs, stress reactions/fractures and other issues with minimalist footwear. Either way the answer is to back off the approach as it’s obviously too much too soon!

My own view is that you can probably get MOST of the benefits of “going minimalist” by just wearing more minimalist footwear casually and NOT on your run (it’s what I’ve finally done); we spend more time NOT running in the shoes we wear everyday right? We may all be “born to run” but sadly not all of us have the proper mechanics, build, and skeletal structure to just get off the couch and expect to NOT get hurt.

Extreme motivation needs to be tempered with extreme patience!


Tuck — “I think they’ve got their conclusion completely backward”

As far as the study goes, I thought it was interesting, and while the injury rate was a bit higher than I would have expected, they’re of the sort that people typically report online. I think they’ve got their conclusion completely backward: “This study supports the idea that, while running in barely there shoes can strengthen lower leg and feet muscles, the lack of cushioning can increase risk of bone injury.” What this study demonstrates is that wearing cushioned shoes prevents your body from learning how to run naturally in a way that prevents injury: the way you evolved to run.

Shoe companies sell you something that makes you dependent on their products. Even a decent runner is so dependent that going to a more natural shoe leads to serious injuries. Why on earth would people want to do that to themselves? 10 weeks sounds like a reasonable adaptation time although longer might be necessary. Mine was about 6 weeks, and I did suffer from various sore bits as I relearned how to run. Once the transition was done, it was well worth it. Years of shin splints are a distant memory.


Tim — “I agree with the findings completely!”

I agree with the findings completely! If you make the transition to VFF running too quickly, you’re bound to hurt yourself and I think that’s exactly what happened here. I remember when I was first starting out—about three months into wearing them—I used a pair of VFF Sprints for a triathlon. The fatigue from the race effort made my form breakdown towards the end, but coupled with adrenaline of the race, I pushed through the discomfort in my foot. I ended up not being able to run for several weeks afterwards because one of my metatarsals ached whenever I tried.

In the study, starting out with a distance of 2 miles and working up to multiple runs of more than that in a week is VERY aggressive. I’d recommend starting out doing less than a quarter mile for the first couple of runs and then slowly building up more, especially if you’re new to running. If you’re a seasoned runner, try adding some VFF running as part of your cool down after a workout. Another tip would be to ease into VFF running with an intermediate shoe that has a zero drop heel and a bit of cushioning (Skora’s offerings or New Balance’s Minimus Zero lineup are examples).


Greg — “The idea that it might take more than a few months to [transition] isn’t absurd”

I’ve been thinking about this a lot, actually.

I think there’re more facets to both the study and its presentation than it seems at first blush. Some minimalists may react strongly to the story, since athletes are often very passionate about their styles/preferences/technique. But hopefully some can approach it with an open mind. I may not have done as much if the study hadn’t mentioned pain in the second metatarsal, which is where I experienced a lot of pain and swelling (but thankfully no fracture) during my transition.

First, what’s wrong with the study: I think that leaving it up to the runners to follow the transition plan on their own is inadequate. It makes a big difference to have someone show/coach you during the transition. Otherwise you’re evaluating varied data since each athlete may understand and take to it differently. Take condoms, for example. Very effective as birth control and STD prevention, but only if used correctly. Problem being that they rarely are. Likewise, the study seems not to control for proper use. All that said, I do agree that it may take longer than the suggested 10 weeks. For me it did. It’s been a little over year and a half since I first ran in FiveFingers, and only in the past week when I finished my first marathon — and in huaraches — did I really feel 100% confident that I’ve finally “got it.” And even so, it’s something that I’m constantly refining. (Walking minimalist is something I STILL need plenty of work in, surprisingly.)

In other words: I don’t think this study is basically “bad” or anything. Most of us have been running/walking in very particular ways for a few decades, so the idea that it might take more than a few months to change it isn’t absurd. Although it may sound as much to runners, given what a historically stubborn bunch we can be.

That’s my $0.02.


What do you think?

Thanks to Tuck, Rob, Greg, and Tim for lending your perspective to this study.

As for my own (Justin’s) view of the study, what jumps out to me are that the study took experienced runners, put them in shoes that were likely very different from their typical shoes, and set them on a fairly one-size-fits-all transition plan to running in toe shoes.

Why do these two things jump out? First, experience matters. The nuances of how we walk, run, and move are educated over the course of thousands of iterations and the shoes we wear affect those iterations — steps — in subtle but profound ways both in how our bodies are built (how strong our muscles and bones are as well as which muscles and bones are strong) and also how those bodies are in motion — the length of our gait, the way we position legs/feet/arms/torso, where our feet touch the ground first, how quickly we lift off, and on and on. When one variable in this incredibly complex equation is changed, we have to adjust everything. What I’d love to see is a study that looks at how long it takes for running form to change (imagine how hard it would be to set this study up!). My hunch is that the more experienced you are running a certain way (and in this case, learned wearing regular shoes versus ultra-minimalist “toe shoes”), the longer it takes to adjust. But even then, your mileage may vary because …

Secondly, success with transition is affected by experience, which means that a one-size-fits-all approach to learning a new way to run is going to be problematic. These adjustments required when switching from a traditional running shoe to a minimalist running shoe are going to be many. They aren’t likely to be made consciously nor are they likely to be made quickly. There’s a reason for the saying “You can’t teach an old dog new tricks.” And while we human beings have an amazing ability to adapt to new circumstances (See: The Brain that Changes Itself), the adaptation takes time and the time and effort required is going to be different for each person. I understand how and why this study applied the transition program suggested by Vibram, but I also believe that one of the reasons minimalist/barefoot shoes can work to improve running form (and ultimately reduce injury) is because they interfere less with the feedback we get through our feet. Since the feedback we get from our bodies (e.g. “ouch this hurts!”) is the only real “coach” most runners have, it follows that you’d want to crank the volume up. Minimalist shoes like FiveFingers go a long way (though not all the way) to doing just that.

What do you make of this study? Does it jive with your personal experience around transitioning to Vibram FiveFingers (or other minimalist footwear)? Let’s hear your thoughts in the comments below!


Study Abstract

Foot Bone Marrow Edema after 10-week Transition to Minimalist Running Shoes


Purpose: Minimalist running shoes are becoming a more popular choice for runners in the past few years. However, there is little conclusive evidence about the advantages or disadvantages of running in these shoes. While performance benefits may exist, injury may also occur from the added stress of running without the benefit of cushioning under the foot. Bone marrow edema can be a manifestation of added stress on the foot. This study measured bone marrow edema in runners’ feet before and after a 10 week period of transitioning from traditional to minimalist running shoes.

Methods: Thirty-six experienced, recreational runners underwent MRIs before and after a 10 week period. Seventeen subjects were in the control group (ran in their traditional shoes only for 10 weeks), while the other 19 were in the experimental group (gradually transitioned to VibramFiveFinger running shoes over 10 weeks). The severity of the bone marrow edema was scored on a range of 0-4 (0 = no bone marrow edema, 3 = edema in more than 50% of the length of the bone). A score of 4 represented a stress fracture.

Results: Pre-training MRI scores were not statistically different between the groups. The post-training MRI scores showed that more subjects in the Vibram group (10 of 19) showed increases in bone marrow edema in at least one bone after the 10 weeks of running than in the control group (p = .009).

Conclusions: Runners interested in transitioning to minimalist running shoes, such as Vibram FiveFingers should transition very slowly and gradually in order to avoid potential stress injury in the foot.

(C)2013The American College of Sports Medicine

* This is why I think Michael Sandler’s advice on transitioning is probably the best around: let your skin be the guide by maximizing the feedback-training-loop through your feet by doing some actual skin-on-the-ground barefoot running.

Photo via Tyson