Over the next few weeks, I am going to be reviewing research articles on running and try to apply this research to real life running.
I really enjoy running and do believe in minimalist running, explained more below. I was excited when I saw this article and I wanted to review for all the runners out there.
Prospective comparison of running injuries between shod and barefoot runners. Altman AR, Davis IS, Br J Sports Med 2016;50:476-480 . You can click on the name of the article to read the abstract.
In the past 5-6 years, I have been fascinated by barefoot running or minimalist running. It was a big trend 4-5 years ago and has since died down. It has been replaced with maximalist minimalist running. Shoes that have very thick soles but minimal forefoot/rearfoot offsets.
To me, minimalist running and barefoot running are not the same thing. Please, let me explain. Minimalist running is using a smaller running shoe, usually a racing flat is the easiest to find these days, with the heel being minimally higher than the forefoot. Personally, an 8mm difference between the heel and forefoot is the largest difference I feel that is allowable for a shoe to still be called ‘minimalist’. There is an issue with my definition, I did not mention the thickness of the sole of the running shoe. Otherwise, this could be considered a minimalist shoe. There should be a protective bottom of the shoe and it will limit some foot movement. I would stay a distinct sole on the bottom of the shoe and will offer some cushioning. This is where the minimalist and barefoot shoe split.
Barefoot shoes have a minimal interface sole, really thin, on the bottom of the shoes. There is absolutely minimal cushioning, if any, with a barefoot shoe. Just like the shoes name, barefoot, there should be no difference in the height of the heel and the forefoot, 0(zero)mm difference. No drop, 0mm, no cushioning.
Anyways, enough of my rant. Let’s get going with the study. The introduction of this study was great. It gives me lots of stats when I give my talks at the different running clinics around Kelowna. Did you know that about 79% of shod, runners that wear shoes, runners have an injury every year! This might be due to the cushioned heel on the running shoe, which changes the way a runner's foot hits the ground. 89% of shod runners land on their heels and the majority of barefoot runners land on their forefoot.
Barefoot running has been associated with increased feedback from the nerves, plantar mechanoreceptors, on the bottom of the foot as well as “...improve static and dynamic stability…” of the foot and ankle. This can help with decreasing ankle sprains.
In addition barefoot runners generally have a higher cadence, more steps per minute, as well as shorter stride length. This has been shown to decrease the loading of hip and knee joints.
The above makes barefoot running sound as if it is great. Decreased hip and knee loading which could mean fewer injuries. Why would anyone want to run with shoes?
There are many reasons to be nervous of barefoot running.
Achilles tendon. That is one big reason that the barefoot running craze has decreased. The Achilles tendon is used a lot more during barefoot running and, in some people, may require a long transition time from shoes to barefoot running. As more barefoot runners land on their forefoot, that loads up the Achilles tendon with a ton of stress. Too much stress too fast, without enough recovery time, can = Achilles tendinitis or tendinopathy if the symptoms continue long enough.
Don’t worry, though, this mobile Kelowna physiotherapy clinic has had some great success working with athletes suffering from Achilles tendinitis. :)
On with the study. The researcher thought that the barefoot population would have fewer musculoskeletal injuries than the shod runners. However, they expected the barefoot runners to have more injuries to the plantar aspect, bottom, of the foot.
They got some runners and started. How did they define a barefoot runner? A barefoot runner had to run at least 50% of their yearly mileage in bare feet. The remainder of the running had to be done in a truly minimalist shoe (no arch support, no reinforced heel counter and no midsole).
226 runners were admitted into the study, 108 shod and 118 barefoot. 25 of the runners decided to stop participation in the study. At the end, there were 94 shod and 107 barefoot runners. 84% compliance rate with the surveys sent out to them.
Interestingly, there were differences between the two groups. This is not something that we like to see in a research study, however, the runners were not randomly assigned to a group. What was different? The barefoot runners were older and higher percentage of them were male, taller and heavier, than their shod counterparts.
There were 346 running related injuries in the study. The injuries were broken down into three categories, plantar surface of the foot, musculoskeletal (MSK) and diagnosed musculoskeletal (DMSK), where the runner actually went and some a professional about their injury. 281 MSK injuries, of those 136 (48%) were DMSK. As an interesting side note, 48% of barefoot runners did not report an injury, whereas only 38% of shoe runners did not report an injury.
There were some big differences in reporting of injuries. Barefoot runners only reported 5 hip injuries while shod runners reported 21! Plantar fasciitis, shod runners = 11, barefoot runners = 3.
30% of barefoot runners reported plantar surface of the foot injuries as opposed to only 6% of shod runners.
When looking at the rates of MSK injury/runner, the barefoot runners were 30% lower. However, the barefoot runners ran less km, when this was taken into account, there was no difference in the injury rate.
"Interestingly, there were 11 cases of plantar fasciitis in the [shod] group compared to only 3 in the [barefoot] group".
The foot was the most commonly injured body part in shod or barefoot runners, in this study. This was the only area of injuries that were higher in the barefoot runners. All other areas, lower leg, knee, hip/groin, ankle, thigh and back, were all lower in barefoot runners. The largest differences were in the hip, knee and ankle joints.
Cuts on the plantar surface of the feet were the most common injury on the feet. This can be the most serious as it can lead an infection in the body. 88% of this type of injury occurred while running barefoot. The use of minimalist shoes greatly decreased the incidence of plantar surface injuries.
One surprising event that was found, was that very few barefoot runners had plantar fasciitis diagnosis. It could be that shod runners tend to land harder on the ground (higher rates of vertical loading). Also, removing the arch support “...promotes strengthening of the arch muscles...” by making them work harder. Each time the foot touches the ground, the muscles of the arch work to slowly lower the arch, that is work eccentrically. Eccentric work, the lengthening of a muscle under load, has been shown to make muscles stronger, not just able to lift stronger but more difficult to tear.
However, Achilles/calf and posterior tibialis strains were higher in the barefoot runners. This can be caused by the large amount of eccentric work these muscles do. As stated above, eccentric work can make muscles to get stronger, but only with appropriate rest periods. Eccentric work really breaks down muscle tissue and gives people more DOMS, delayed onset muscle soreness, initially. However, after the body adapts to the increased demands, there is less muscle soreness.
The knee is the most common injury site in runners. Of knee injuries, iliotibial band syndrome and patellofemoral pain syndrome, PFPS, are a couple of the most common. These two injuries were more common in shod runners, in the present study.
There was quite an extensive write up, the good portion of a paragraph, about PFPS. PFPS sounds really scary! It is simply pain behind the kneecap. Your kneecap is called the patella and your thigh bone is called the femur. When you bend your knee, the kneecap and femur touch. This is called your patellofemoral joint. That is it. There are thought to be many different causes of PFPS. One possible cause of PFPS is high patellofemoral contact stress. This is how hard the back of the knee cap is forced against the femur. Barefoot runners have lower patellofemoral contact stresses. This pain behind the kneecap is one of, if not the most common injury resolved with starting to run while barefoot.
The study was not perfect. As mentioned previously, both groups of runners were not equal. As well, many of the barefoot runners, 63%, have only been running barefoot between 6 - 12 months. This can lead to concerns that some of the barefoot running injuries might be to some of the runners still transitioning to run barefoot.
“...This study suggest[s] that barefoot runners sustain fewer overall MSK injuries compared to their shod counterparts”. This statement did not hold up when running volume was taken into consideration.
I liked this study, as it is not a study that can be done with a randomized controlled trial. You cannot get a bunch of runners and say that this group is going to be barefoot and this group is going to wear shoes. You would have to make sure the barefoot runners keep running barefoot and give them a very good transition program. It would really be interesting to contact all of these runners again in a few years and check again on their injuries. That would increase the average of the barefoot runners from 1.65 years of running barefoot, to 3-4 years. Then there would be much more adaptation for the runners tissues. This would make for a great study. I feel that would give a much better representation of adapted barefoot runners compared to shod runners.
As much as I like the idea of barefoot running. I am a realist about the subject. Running barefoot where I live, in Kelowna, would be difficult. The practicality of running in the city in summer, not to mention winter, would be difficult with pavement temperature, thin skinned bottom of the feet and dodging broken glass and other sharp objects would prove to be a challenge. In addition, the Vibram 5 finger shoes are not the most socially acceptable shoes out there. I really like the Inov-8 shoes. I find that they are very comfortable with minimal break-in time. However, they are difficult to find. I went to Calgary, a couple of weeks ago, and I went to the two stores that sell Inov-8 shoes. I was disappointed as there was only one pair of shoes in my size and only 3 styles in both stores, combined. Great shoes, highly recommended, if you can get your hands on a pair.
It is getting more and more difficult to find a reasonably priced, minimalist shoe to run in. I have run in the New Balance Minimus shoe for the past 4-5 years. I am on my second last pair, probably only 3-4 months left in them. Then I will have to start seriously looking for a new minimalist shoe to run in.
Any suggestions from my readers on which minimalist running shoes I should be looking at?