Posted by steve
At the same time, there has been a backlash against both minimalist shoes and more importantly running form that is demonstrated in such articles as Matt Fitzgerald’s latest one (here). First, let me say that I think disagreement is a good thing and I actually appreciate the back lash. As you may know, one of my central guiding principles is that we tend to overemphasize “new” discoveries until they settle down and find their rightful place. Secondly, Pete Larson posted a long but entertaining video of the Newton running shoe conference (http://www.runblogger.com/2010/09/newton-panel-discussion-on-natural.html) that also touched a nerve and needed a response.
I want to use this post to address the major issues in the running form and running shoe industry, and see where we are going and what mistakes are likely to occur.
It’s important to understand the history of the running form and running shoe movement. It’s often given lip service without considering where we actually came from. There seems to be this idea that running form or minimalist shoes are some new idea. In fact, I love how Newton basically stated they were the company that first started the minimalist shift…oh my.
Let’s start with running form. Back in 1964 a track coach named Toni Nett did a study on the foot strike of top German runners. He looked at these elite runners running 100m up to the marathon and studied their foot strikes during those events. What did he find? During the sprints, the runners landed up towards the ball of the foot and then let their heel come down afterwards. During the middle distance events, most runners landed what we’d call mid-foot. Finally, during the long events such as the marathon, runners landed what we’d call whole foot, making initial contact somewhere underneath that couple inch area from the front to the back of the arch. No heel striking going on, even at marathon speeds, for the majority of the runners. In the training literature from those days, you’ll see that most of it recommends Nett’s viewpoint. The few books on biomechanics I have from this 50’s-60’s era all show what is basically a midfoot/wholefoot plant as the way to run. There were some disagreements, but for the most part we can say that coaches did not support a heel strike. The ones who did mostly limited their support to slower jogging.
Where’d the heel come in to play?
Before 1980, the majority of the studies that I could find on running biomechanics focused on elite or sub-elite runners. For instance, a 1977 study by Cavanagh compared world class and good runners biomechanically and gave us all sorts of interesting biomechanical data. In fact in that study, foot strike was given little mention, although they did find that at foot strike the foot was parallel to the ground or slightly plantar flexed. What that means is that the runners either struck the ground whole foot or with a midfoot/forefoot initial touch. Additionally, the runners landed almost exactly under their knee with only around 2 degrees off from accomplishing this.
However, in the 1980’s something changed. The research started pointing towards distance runners needing to heel strike. A 1983 study by Kerr et al. declared that around 80% of runners heel strike. Thus the conclusion was made that heel striking must be how running was supposed to be done. All the way through to today, almost every research study I could find declared that running was a heel-ball-toe activity. Various justifications such as the role of heel fat pad were given as to why we should land on our heels. The funny thing is another study came out in 1983 that mimicked Nett’s study almost 20 years earlier. It looked at elite runners from the 100m on up, and found that around 76% made contact that would be either considered flat foot, midfoot, or forefoot. Similarly to Nett, he found that sprinters made contact up near the ball of the foot, while most distance runners landed flat.
What happened in the 1970’s and 80’s?
Why did we change? How’d we go from studies looking at footstike saying that heel striking was evil, to some that showed everyone should do it?
If you know even anything about the history of running, answer me this. When did the Running boom occur?
We went from a sport filled with elites or crazy people who liked running to one of the masses. Thanks to Frank Shorter’s marathon victory, Ken Cooper’s aerobics, and a whole slew of other factors, running started gaining popularity with the masses.
So by the time that 1983 study took place, we were no longer looking at just elite runners, we’re looking at recreational runners and the tides had turned. The demographics had changed, but had foot strike changed that much?
The shoe industry
Take a brief look at the history of running shoes and you’ll see a pretty abrupt transition point. Take a look at the pictures in this article and see if you notice anything:
We went from a relatively flat, minimal shoe to an ever increasing “cushioning” system. It starts with slightly raised heel to give more cushioning and then transformed into a whole slab of almost inch thick cushioning for the whole foot. Our distance from the ground went from a few cm to almost an inch. It’s obvious what happened but the important question is WHY did it happen?
Like most crazy changes, there were several interplaying factors that led to the change.
1. Masses started running
No one worried about cushioning, as you can see, until the masses started running. As a whole slew of new runners who weren’t used to training for races or competition joined the running movement, the demographics changed from a slender fit runner to someone using running to get in shape. For people who have almost exclusively walked for 30-40-50years of their life, you often see them heel strike when they start running. Why? Because their initial speed is in that walk-run transition area so they kind of shuffle with an in-between running and walking motion. Secondly, they are used to walking, not running, and in a walk you heel strike.
2. Shoe companies used some misguided logic.
The running boom meant people going from nothing to running in no time. As you all know, rapid changes no matter what shoe you wear, causes injuries. So you get new runners who likely are getting some injuries and complaining about the hard shoes they have, being the new customer. The shoe companies had two options, and I’ve talked to coaches who were around during that time who corroborated this with me. The first option was what the coaches said: the problem isn’t the cushioning, it’s the heel strike, so the solution is change the foot strike. The second option was that runners needed heel cushioning. They chose option number two and that’s why you get the start of small heel cushioning devices.
3. The use of a force platform
In the 1970’s and 80’s the use of a force platform to measure ground reaction forces became standard. As so often happens, when we can all of the sudden measure something we couldn’t before, we put too much meaning into the results. It happens with every measurement, VO2, lactate, heart rate, etc. What happened is that all of the sudden the researchers and doctors saw the large amount of impact forces that the body withstood during running. They saw numbers that were several times the body weight of the runners. I don’t blame them for thinking “wow that’s a lot of force going up the leg! We should add something to reduce that.” Using this logic, you got companies slapping as much cushioning as they could get on the bottom of the shoe.
The problem is that they didn’t know what those numbers meant. They had no idea if 2-3x BW was bad or caused injuries or if the pattern of the GRF mattered at all. It just sounded like a lot of forces, so we should try and minimize it. If you’ve read this blog before, you’d know that the total GRF isn’t that important. It’s the rate of loading, and the initial peak that is present in the heel strike but not midfoot that seems to be a big deal.
That’s the short version of how we got to where we are today. Briefly let’s go over the minimalist movement:
Where did the minimalist/barefoot movement start?
Cross country runners, coaches, and competitive runners. I’m not going to claim to know the exact dates or even give a time frame, but I do know that for decades competitive runners and coaches have been on the forefront of such changes. Everyone’s heard the Stanford cross country story of them doing barefoot jogging and that’s how Nike came up with the Free. What most people fail to realize is that this was going on around the country with many competitive teams for years. It’s what you did. I remember back in High School doing cool down laps around the inside of the track barefoot. Similarly, my High School coach would have us take our shoes off and do barefoot strides to work on form. In particular, we had one runner who was very good but a bad heel banger (what we called heel striking…), so to force him to change coach would make him do barefoot strides on the track. And we certainly were not unique. You can go much further back then my high school days and find similar stories about barefoot running. You can go back to the days of Percy Cerutty making his athletes take their shoes off and run barefoot through the sand dunes and hills as part of their workout if you want to. Similarly, I can give you stories of individuals training exclusively in racing flats or a similar flat. The point is. It’s not new, no one suddenly invented minimalism. It’s just gained popularity in the mainstream as a backlash to the increasingly big shoes. It was bound to happen sometime, it's just that a series of events propelled it into the masses.
Where do shoes and form go from here?
In my previous blog post, I asked you where the running shoe industry was going. There were some great answers given, but most focused on the minimalist approach. For the most part, I’m right there with you, but I’d like to suggest that we err on the side of caution. Pete Larson posted an interesting panel discussion at a Newton shoes conference that gives some interesting insights into where the shoe industry might be headed. You can watch it yourself, but let me highlight a couple of things I noticed. I’m doing this not to critique the panelist but to point out that we have a LONG way to go in understanding running form.
1. The center of Mass.
The foot does not land underneath the COM. Pete dissected this. I dissected this. Research dissected it. I found a study as far back as that 1977 Cavanagh study that found elite and good runners landed an average about 25cm in front of their COM. Landing underneath the COM is a great CUE, however it should not be used as a descriptor.
2. Barefoot running isn’t a cure all.
Despite how many times it is said, people can still land heel first when barefoot. You see this in the Lieberman data. Why? Because of so many years of ingrained motor programming. Even with the sensory feedback, it’s not enough to tell the body to change.
3. Stop trying to get quick.
Several panelists talked about trying to land under the COM to minimize the GRF. Let’s get something straight. You need time for impact forces, as I’ve pointed out here before. They are going to occur. And guess what, as you go faster you need more GRF…. It’s not evil. Look at Weyend’s studies on GRF and running, faster sprinters impart more force into the ground than slower ones. Or put in other words, the faster you run, the more GRF you’re going to need. If you ever want to run fast, you’re going to have to increase GRF. So, don’t get obsessed with minimizing total GRF. If you do that, you’ll be going really slow and running really strangely. Do NOT fall into this trap.
4. There is a difference between Dynamic and Static abilities.
While balance is important, standing on one leg is completely different from the balance it takes to be on a foot for .1-.2 tenths of a second. Many experts, beyond those on the panelist, often say balance on one leg to check for running related balance. However, the idea that single leg balance in a static position relates to the balance needed in the dynamic state of running is weak at best. It’s falling into the same trap that stretching fell into. For years people thought static stretching was essential for dynamic flexibility. It’s only recently that people have realized that the range of motion a person can go through in the running motion has little relation to the range of motion they go through statically.
For example. The athlete below couldn’t touch his toes statically, but looks pretty flexible dynamically:
5. Newton doesn’t care about performance?
Okay, this one seems a little harsh. But after sitting here and listening to Newton people talk about how you “lift the core” and heel to move and not push using your hamstring, I think it’s reasonable to say the above. It’s kind of scary that a shoe company that supposedly thinks their product will improve performance basis its ideal running form on a bunch of bunk ideas/science. At the very end of the panel, someone questioned Newton on this, and they basically said that only in “sprinting” do you need to push….So my conclusion is that newton’s are built for running 8+min miles all day…wonderful
6. Walking, running, and sprinting blend together
It’s important to remember that walking, running, and sprinting blend together. Walking is the most distinct and different but there is going to be a speed that is called the walk-run transition that represents a transition point. During this phase it feels awkward to run so slow or walk so fast. Thus, as mentioned earlier, a lot of times you get a weird kind of mix shuffle action at these in between speeds. It’s one of the reasons why new runners who jog really slow adopt a heel strike like shuffle. At these speeds, the Newton panel is correct in that you don’t need much hip extension/force application because it doesn’t take much force to move. But as we get faster into a run and then into a sprint, research shows that more force application is needed and along with that more hip extension occurs. This should make sense, as the muscles around the hip function as the speed governor. Want to speed up, use them more. Which brings us to the run/sprint transition. Unlike walking, sprinting is very similar to running. The difference is force application and range of motion. The hip extension is greater, the leg cycles through a greater motion, and the arms go through a greater range of motion. But it’s the same basic motion, it just happens faster and in a greater range of motion.
7. Pay attention to the track coaches
Number 5 brings us to the above statement and one of my other favorite statements: Coaches innovate and come up with it Scientists explain why it works. Whenever it happens the other way around, it goes horribly wrong. You can look at shoes or the rise of hard interval training/low volume mileage during the 90’s. Yes, I am being harsh, but for the most part the top track coaches have been teaching correct biomechanics for decades. Yes, we argue about subtle differences like a pawback and dosiflexion, but no one is saying don’t apply force. That’s what scares me. With running form gaining in popularity, you see good intentioned people getting horrible ideas on what actual running form should look like. You can’t really blame them. For example, the scientists were taught heel-ball-toe growing up. It’s hard to completely change your ideas and know where to look for correct information. Bottom line is I’d put my trust in the trial and error of elite coaches and elite athletes figuring things out, instead of the people who are trying to make a buck off a trend with the masses.
The point isn't to needlessly critique shoe companies or the panelists in the Newton shoe conference. In fact, many do excelent work. The point is that we should be careful with where we go from here. We don't want to make the mistakes of the past and rely on bunk science, incorrect ideas, and bad interpretation of research.
Part 2 will be on how do we figure out what's right and where do we go.