Every once in awhile in life you get the feeling that you are part of something big. Something that might really make a difference beyond just the small pool of people that you interact with on a regular basis. That was how I felt as I sat in a darkened conference room at the National Conservation Training Center on Sunday morning, listening to a recap of what I had learned over the previous two days.
As I indicated in my previous post, I spent the past weekend in Shepherdstown, WV attending a three-day course called “New Trends in the Prevention of Running Injuries.” The course is taught primarily by Blaise Dubois (see photo at left), a Canadian physiotherapist from Quebec City, with assistance from Sean Cannon, a physiotherapist and international level sprint canoe racer. I didn’t get a chance to look through course materials prior to arriving, and as such had little idea of what to expect. However, I figured that any knowledge I could glean about running injuries would be helpful, particularly since I am once again teaching Exercise Physiology this semester at my college. What I left with was near complete validation of just about everything I believe in with regard to running injury prevention and running footwear. I can’t tell you how good it feels to be in a room with a diverse group of forty-some people, including health care professionals, academics, shoe designers, writers, athletes, and form coaches who all largely agree that our current approach to running form and footwear is deeply flawed.
I’ll start by saying that Blaise Dubois is an amazingly good speaker, and that he put an immense amount of work into developing the course (this was the first time it has been taught in the United States). He has the ability to mix humor and hard science in a way that makes his presentation engaging, convincing, and easy to follow, and his command of the relevant scientific literature is impressive. Blaise regularly works with top elite runners in Canada, and as evidence of his level of expertise, he recounted a story about how he once worked with Hicham el Guerrouj. If you don’t know who el Guerrouj is, look up who currently holds the world record for the 1500m or mile. Point being – Blaise has been entrusted to care for some of the best runners in the world, and it was reassuring to hear a highly accomplished physiotherapist talk quite honestly and frankly about the problems with modern shoes and how they alter natural running form. Blaise’s partner in teaching the course, Sean Cannon, also did a great job, and the two have a great back-and-forth and kept things light despite the complex nature of the topics being discussed. If you ever get a chance to attend this course, do it – it’s well worth it (for more info, visit the course website here).
The expertise present in the room wasn’t just limited to Blaise and Sean. Other presenters included Jay Dicharry from the University of Virginia SPEED Clinic – quite possibly the most technologically advanced gait analysis lab in the world (check out this video series on Jay’s lab by Running Times). Dr. Ray McClanahan is a podiatrist at NW Foot & Ankle in Portland, Oregon who prefers to try and restore the foot to its natural state rather than rely on orthotic intervention as a first line of treatment for foot pathologies (he’s also a darn good runner with a 5K PR of 13:56!). Dr. Craig Richards, known best for writing the paper that questioned the role of modern running shoes in injury prevention, flew in from Australia to attend and speak. Dr. Mark Cucuzzella, a family physician from Shepherdstown and owner of the TR Treads Natural Running and Walking Store organized and spoke at the course. Other attendees include Danny Dreyer, form coach and author of Chi Running, Ian Adamson from Newton Running, Jeff Horowitz from Competitor.com, and Peter Vigneron from Runner’s World. The course is geared toward medical professionals, and a variety of physical therapists (many from the military), orthopedic physicians, chiropractors, and personal trainers were in attendance. It was really quite a diverse and highly knowledgeable crowd.
There’s really so much that I could recount from the experience, but in this post I simply want to walk through what I found to be some of the main points that I came away with.
1. Running is good for humans – it has been shown to significantly reduce both mortality and disability risk.
2. Running doesn’t ruin our knees, in fact it might actually benefit knee cartilage over the long term (see this NY Times article for more)
3. Lots of runners get hurt – range is 20-80% depending on the study.
4. Most running injuries are overuse injuries that can be attributed to stubborn and obsessive runners doing too much too soon. In doing this, runners exceed their body’s stress threshold and something gives. The end result is an injury. I write a post largely devoted to the topic of overuse injuries in runners a few months ago.
5. Many running injuries are associated with some kind of change in a runner’s training. Could be a change in shoes, running surface (e.g., running on the treadmill all winter then resuming the same mileage on the roads when it warms up, mileage, volume of speedwork, etc).
6. From pre-1970 to today, running shoes have gotten progressively bigger and bulkier, with lots of added cushion, proprietary “technology”, and raised heels.
7. There is no scientific evidence supporting the efficacy of “big, bulky shoes” (Blaise’s phrase describing the modern running shoe) with extensive cushioning and a large heel lift for the prevention of running injuries. However, we also have no direct evidence that big, bulky shoes cause injuries, or that minimalist shoes or barefoot running are better at injury prevention. More studies are needed!!!
8. Most “technological features” in modern running shoes are likely nothing more than marketing gimmicks designed to appeal to customers and sell more shoes. Little objective and/or publicly available evidence is available to support the efficacy of proprietary technology in shoes.
9. Big, bulky shoes change how we run. They cause us to run in a very different way than we do when we run barefoot, which is how the human body evolved to run (see Lieberman et al., 2010, Kerrigan et al., 2009, and Squadrone and Gallozi, 2009 for some recent examples of how shoes change our gait). In general, barefoot running causes us to run with a shorter, quicker stride and a forefoot landing. Many additional examples of studies looking at barefoot vs. shod gait are available, and a number of them are cited in this post by Phil Shaw).
10. Higher vertical impact loading rates (how fast impact is applied to the body – think punching a wall with your bare fist vs. a boxing glove) have been linked to injuries like lower extremity stress fractures (see this review paper by Zadpoor and Nikooyan, 2011). Conversely, Nigg, 1997 reports results of what appears to be an unpublished graduate thesis suggesting that impact force and loading rate are not linked to injury, and that increased loading rate was actually associated with fewer injuries. However, this analysis looked at short term injuries and did not look at injuries by specific type. I am hesitant when trying to interpret results from research that has not been published in a peer-reviewed journal, and currently am trying to get ahold of the thesis. In contrast to Nigg’s findings, Davis et al. report results of a prospective study in a conference abstract showing that vertical impact peak and vertical loading rate are linked to a higher incidence of running injury. More studies are needed!!!
11. Forefoot striking has been shown to reduce vertical impact peak (many studies, Lieberman et al., 2010 is a recent example) and vertical impact loading rate (Oakley and Pratt, 1988; Williams et al., 2000) relative to heel striking. Data showing no difference between forefoot and rearfoot impact loading rate is out there (e.g., Laughton et al., 2003), but data are limited that involve people well acclimated to multiple landing types. Data on loading rates are sometimes difficult to interpret if runners are not acclimated to a barefoot running style – for example, De Wit et al., 2000 showed dramatically increased vertical loading rate in barefoot runners compared to shod runners, but their barefoot runners were heel striking. One would fully expect a barefoot heel strike to exhibit a higher loading rate since little cushion other than the heel fat pad is present to slow down force application. Lieberman et al., 2010 showed that habitually barefoot runners overwhelmingly land on the forefoot, which suggests caution when interpreting studies of barefoot heel strikers (who were probably unaccustomed to running barefoot).
12. Big, bulky shoes dramatically increase torques on the knee and hip joints compared to running barefoot (Kerrigan et al., 2009). In particular, running in shoes increases a knee varus torque, which forces the leg into a more bowlegged position and compresses the medial portion of the knee (a primary location for osteoarthritis). We don’t yet know the significance of this to injury risk, or how much additional torque is too much. However, if one can avoid torqueing joints by emulating barefoot running, this might not be a bad thing.
13. Simply increasing cadence (stride rate) may provide positive benefits in terms of joint loading. For example, Heiderscheit et al. 2011 showed that running with a faster cadence/higher stride rate (5-10% increase) reduced loading on the knee and hip, allowed for a more level carriage of the center of mass (less vertical oscillation), shortened stride length, and created less braking impulse. Read my post on the Heiderscheit paper here.
14. Studies that have assigned shoes to runners based on static measures of the foot (e.g., arch height, foot posture index) have shown little benefit when shoes are assigned either appropriately vs. inappropriately based on the static measure (Ryan et al., 2010; Knapik et al., 2009; Knapik et al., 2010a; Knapik et al., 2010b). These results show that either static measures are not a good way to assign shoes (so much for the wet footprint test!), or that pronation control is not a good basis on which to choose a shoe. For summaries of this work, read my post on the pronation control paradigm or a great article on the topic from Gretchen Reynolds of the NY Times.
15. Pronation control is not a good basis on which to choose a shoe, and should not be the foundation upon which such decisions are made (as is currently the situation). Read Nigg, 2001 for more. Benno Nigg also just published a book in which he tears apart the pronation control paradigm.
16. Our feet are screwed up. Ray McClanahan talked about how our shoes are too narrow, and narrow shoes disfigure the foot. If you look at your foot and notice the big and little toes pointing toward the middle of the foot, it likely means that your foot has molded to the shape of a shoe with a narrow, pointed toebox. The picture at left from Edward Munson’s book “The Soldier’s Foot and the Military Shoe” provides a very visual example of this. He believes that mis-alignment of the big toe compromises our stability and can lead to problems with the running gait. One simple way to see just how narrow your shoes are – take out an insole and stand on it (weight-bearing). Notice how much your foot spills over the sides of the insole. That is the portion of your foot that gets restricted by your shoe.
I could go on, but in the interest of keeping this post from going too long, I’ll stop here for now. As you can see from what I have written above, there is a lot of interesting science out there that calls into question the efficacy of the ubiquitous modern running shoe, and also questions whether how we run might be contributing to high injury rates in runners. There is a lot we don’t know, and studies linking footwear or lack thereof directly to injury are lacking right now – we need more good research!
One of the things that also came through loud and clear is that barefoot running is our default. It is how we evolved, and modern shoes are a change from that default. Thus, the burden of proof should be to prove that we are better off running in big, bulky shoes. People often seem to think that the notion that we should run in a way that emulates the barefoot gait is radical (whether actually barefoot or in minimal shoes), but in reality it’s what our species has done for nearly 2 million years prior to about 1970. Modern shoes have changed that, and the consequences of this change are what we are all trying to figure out. Is barefoot-style better? Maybe, we really don’t know yet, but science regarding impact, joint torques, etc. seem to suggest that a barefoot-style gait moves things in a positive direction. Should you throw away your shoes? If you are running well and have no injury history, there may be no reason to. However, if you have been saddled with injuries, a change to a minimalist shoe and some form work might be of benefit. Blaise and Sean both prescribe racing flats and advocate gait retraining in their clinical practice – I will talk about their form approach in a subsequent post. Due to anecdotal reports from readers, as well as experience with my own wife (a story for another day), I am a believer in their approach. One key point to make here though, is that any change that is made must be:
GRADUAL AND PROGRESSIVE!
Your body is most likely adapted to wearing big, bulky shoes. Rushing into form change or a minimalist shoe too quickly can be a recipe for disaster. Change needs to be approached as a long term process, and the body will need time to adapt. Again, more on their approach in a future post.
I’ll end this post by putting in another plug for Blaise and Sean’s course – it was a phenomenal experience, and one that I won’t soon forget. If you want to read a bit about their philosophy, they have a short book that goes over many of the things that I have discussed in this post – you can order it from their website at: https://secure.therunningclinic.ca/en/runners-information/ebook.php.
Also, check out their recommended shoe webpage – I particularly like the shoes to avoid tab: http://www.therunningclinic.ca/en/runners-information/recommended-shoes.php
If you have any thoughts, comments, or questions, please leave a comment!