“Over-Reaction? Under-Reaction? The REAL Truth on Barefoot Training

Here is a great article by Andy Clower, ATC.  You decide for yourself.

The hottest and latest trend in our ever-changing running community is the transition from maximal support shoes into the new “minimal” shoes, or even into barefoot training. Over the decades of the recreational running boom, shoe companies and professionals have been touting their footwear or technique as the only way to go to not only run faster, but also prevent any type of harm or injury that may come your way.

The shoe industry has been reacting, for better or worse, to the latest research, market trends, and injury numbers since recreational running took off in the mid-1970’s. You can find shoes ranging from 1+ inches of foam padding with a “rocker-shaped” sole to a “glove” designed to fit around your foot with a little more than a few millimeters of rubber between the foot and the ground, and everything in between. There are even those who’ve chosen to forgo being shod all together, and venture out with nothing between their foot and the ground. There are advocates and opponents of every style, with claims, and research, supporting both ends of the spectrum.

There have been overreactions and under-reactions in the running shoe industry for decades. The original over-reaction/under-reaction came in 1987, when the first maximum padded shoe with air pockets was released in response to the growing number of running-related injuries. Some cutting-edge researchers were able to measure impact forces being absorbed by the feet in the running-shoe-at-the-time, which would now be considered minimal.(1, 2) They determined that these high impact forces were the cause of injuries, not totally taking into consideration that these runners were new runners and previous “desk athletes” who hadn’t run since their youth. (Until the mid to late 70’s, typically, the only people who ran were the competitive, Olympic-level athletes.)

Over-Reaction: “The human body isn’t designed to absorb the forces of running, so we need to pad and support it as much as possible to disperse that force.” Under-Reaction: “People should be able to just go out and run with out building up a prior-strength base, or progressing slowly and appropriately to handle these new loads. Adding more padding and support to the shoe will take care of that for them.”

Unfortunately, this well-intended “fix” didn’t help as it much as it was supposed to, and running injuries continued on. Many would argue that the occurrence of injuries increased from 1987 and on, but there aren’t any numbers to back up that claim, yet. Recreational running popularity increased incrementally from 1987 onward, and of course, with the number of participants increasing, the number of injuries will increase. The question is, did the rate of running injuries increase? The common belief is "yes," but an extensive retrospective study covering all injuries and their causes, as well as the number of reported “recreational runners” over the past 37 years would be required to get a definitive answer. That study, to date, has not been done yet, and would take years to complete, if it’s even possible. We don’t know for certain that running injuries increased with the advent and evolution of the new running shoe, but researchers are pretty certain that they didn’t decrease, either, which was the intended effect of these shoes.

The hot new "minimal" shoe that seemingly every shoe company is beginning to delve into is being touted as the new answer to the problem. There are many varieties of this new style shoe, with no clear-cut definition of what a “minimal shoe” actually is. Based on most discussions, and the various options, it seems a “minimal shoe” would be one that has less than 1 inch of rubber in the insole, is flexible, and no heel to toe drop (meaning the shoe is completely flat, no raised heel).

The proposed benefit of this new style is a more “natural” approach to running and foot biomechanics. It’s been well documented, at this point, that a heel strike in running is what produces impact forces of up to 7 times the runner’s body-weight. A forefoot strike has been shown to lessen that impact to approximately 2-3 times the runner’s body-weight, according to research done at Harvard’s barefoot running lab, and Dr. Daniel Lieberman (3). Their data shows that most runners who run in traditional running shoes have been shown to run with a heel strike vs. a forefoot strike. The absence of the foam padding in the minimal shoes is intended to allow the runner to self-correct his/her gait by making the heel strike painful, and opting to land in the mid or forefoot instead-a more “natural” gait. Over-Reaction: “The thick foam padding between the foot and the ground is the cause of the poor running mechanics of the modern runner by ‘dampening’ the foot’s ability to sense the amount of impact going through it, allowing it to do more than it’s designed to do.” Under-Reaction: “All or most of the padding should be removed between the foot and the ground. People should be able to put these shoes on, go out and run, and let their body adjust and self-correct by itself, naturally. It’s the shoe, not the change in gait that decreases the impact.”

Has this new approach worked? Unfortunately, this trend is too new for any reliable data to be published showing a true reduction of injuries and performance improvement. There are claims world-wide (all anecdotal, at this point) from runners who went minimal and cured all of their running injury problems. But there are almost as many claims (as well as reports from MD’s, Podiatrists, and PT’s) that the switch from maximal support to minimal caused all sorts of injury issues that weren’t existent previously or old issues re-exacerbated.

So who’s telling the truth? What’s the best option to improve your running performance and reduce your risk of injury?

The truth is, there are pros and cons to every shoe choice, and there is no clear-cut one choice that is best for everybody.

Though the extra-padded, maximal supportive shoe may have been an over-reaction, there are some pros to these shoes. Many people have deficiencies in their feet that need that extra support and cushioning to allow them to get out the door for a jog. Finding a shoe that helps shape the foot into a better “lever” for pushing off and supporting the body could prove to be beneficial for some people, and there have been many runners, from average to elite, who have succeeded in this style of shoe. In fact, world records have been recorded in this type of shoe.

The cons of this style of shoe would be the ramifications of relying on an external apparatus (the shoe) to correct and support our deficiencies. Research has shown that foot and toe musculature could actually begin to “shut off” as the demand for activation has been taken over by the shoe that’s designed to do the job for the foot. Foot integrity will continue to digress, as the “use it or lose it” principle that we apply to all of our other muscles and systems apply to the feet, as well. Muscles respond and activate with joint movement (called an “arthrokinetic reflex”). Prolonged reliance on an overly supportive shoe could lead to deteriorating foot musculature, and eventually, structure, as these shoes are designed to keep the joints of the mid-foot as stable and still as possible. Also, the impact forces from the typical heel strike in these shoes can be a detriment to the feet, knees, hips, and back over time.

It is possible to run with a forefoot strike in these shoes and mitigate some of the effects of the stiff mid-foot and heel strike. But, you must be willing to put in the work and time to develop this new gait and progress slowly and appropriately.

The minimal shoe, designed to be more “natural,” has pros and cons, as well, and could also be considered an over-reaction. The pros of these shoes is the proximity of the foot to the ground, and the absence of artificial “lift” in the heel that typically limits the spring of the ankle-joint from fully loading.

One term that’s being touted as a benefit from these shoes is “increased proprioception” in the feet. Proprioception is a term that’s thrown around, but never really clearly defined or explained. What is proprioception? Essentially, it’s your brain’s 3-D map of your body (4, 5), made up of a system of millions of tiny receptors that continually feed the brain information- 11-20 million signals per second! These receptors monitor everything from movement to pressure, temperature, “pain,” and many other signals. The majority of these receptors live in or around joints and also into muscles and other structures. Over 24% of the joints in the body live in the feet, and the highest density of pressure-receptors are housed in the bottom of the feet- our posture is aligned initially based off of the information the brain receives from those receptors. Having less between the ground and the feet, allowing those receptors to react and respond more quickly and accurately, is one of the major reported benefits of a minimal soled shoe. Another reported benefit of these shoes is as muscle activation increases due to heightened foot activity, foot strength and structure also improve. Given the body’s ability to adapt and continually strengthen in response to loads place on it, the potential for longevity and speed are great. This is a new era that has been previously untapped as advances in training for speed, strength, and injury-prevention are being combined with this new approach.

There are also negatives to training in this type of shoe, as well. One negative is the idea that “minimal shoe training” is the same as barefoot training. Many studies were based on comparing “shod” training to barefoot training, and the results of these studies were the basis for the design of these shoes. There are anthropological studies that have linked fewer incidences of running injuries in un-shod populations(6), but, being surrounded by asphalt and concrete, we don’t exactly live in the same environment as these people. And, for the reasons mentioned in the previous paragraph, minimal shoe training is not barefoot training. Anything between the foot and the ground slows the reaction of the receptors, dampens response, and could potentially lead to injury. Slower response with a much thinner protective barrier leaves the runner more susceptible to any sort of puncture-type injuries from landing on rocks or sharp objects. On top of reducing the protective barrier, support is dramatically reduced as well. Removing the mid-foot support and heel lift place a brand new load on the foot musculature and the Achilles tendon that previously were mitigated by the shoe, as well as new stress on the metatarsals. Achilles tendon strains and metatarsal stress fractures have been the most widely reported injuries with the transition into the minimal shoe. Again, you must be willing to progress slowly and appropriately to allow your body to adapt to reap the benefits of this type of training. Many don’t have the time or the patience to do this!

There are shoes that fall in between these two extremes, as well. The middle-of-the-road shoes that are now being referred to as “reduced” shoes combine the flexibility and lighter weight of the minimal shoe with the padding (though reduced), heel lift, and shape of the maximal shoe, giving runners the “best of both worlds.” These shoes provide the foot the opportunity to move more freely and naturally through the gait cycle, while giving the foot some padding and support to help disperse the impact as well as a protective barrier to guard against those unwanted sharp or pointy objects you may step on in your trek through the concrete jungle.

The largest over-reaction is the blame or credit placed on the shoe, and the removal of responsibility from the runner and/or coach. Runners can succeed and thrive in any environment. (In this case, the shoe would be the environment.) Expecting the shoe itself to alleviate all of our aches and pains and compensations is an under-reaction, and too easy of an answer for real life. A running step places the body under a load of anywhere from 2 to 7 times the athlete’s body-weight. A typical runner averages 1,500 steps per mile. A 150-pound runner will bear 300-1,050 lbs. per step- up to 1.575 million pounds per mile. No strength training session in a gym could ever match that, and no shoe alone can bear the brunt of that load to allow the runner to continue on without risk of injury.

The truth is, shoes can help or hurt. If you're wearing anything on your feet, you're not barefoot training like our ancestors did- minimal is not barefoot, and while close, is still not 100% natural.

What’s the best option for you? There are many factors that play into this decision. Some things to consider are: running experience, time dedicated for training, current foot and body health, what do you spend most of your time doing and wearing? Another, maybe more important, thing to consider is: What is your training goal?

Every program, be it running, strength training, athletic training, or whatever, should have a goal. If your goal is general health and fitness, you enjoy running but don’t have much time to work on your body and strength and spend most of your time in the office in dress shoes, you may want to consider a shoe with more cushion and some flexibility for comfort.

If you’re a more intense runner, are able to put in more time during the week for strength and mobility work, and are looking to progress into something more natural with potential for a high payoff in how you feel and potential performance, a more minimal shoe may work for you.

There’s one rule/principle that should drive your training, and your decision: the SAID Principle (Specific Adaptation to Imposed Demand). This means your body always adapts to exactly what it does. It’s the number one principle behind corrective, strength, and performance training. If you want to get better at something, you have to train for that thing specifically. As a society, at this point, we’ve typically spent more time in shoes than barefoot, so we’ve essentially adapted to wearing shoes. Training barefoot (or close) to improve your quality of life that mostly exists in shoes goes against this principle, and is most likely an over-reaction.

What do you want to be good at, and based on the information that’s out, what type of footwear is required and will give you the best opportunity to succeed? There’s no definite answer for everyone. We all have different backgrounds, bodies, and training goals. As in every aspect of life, there are those who fit into either of the two extremes, but at the end of the day, somewhere in the middle is where most will land and succeed.

Here are some additional resources if you want to really research the subject.

Clarke, T.E., Frederick, E.C., Cooper, L.B., 1983. The effects of shoe cushioning upon ground reaction forces in running. International Journal of Sports Medicine 4, 247–251.

James, S.J., Bates, B.T., Osterning, L.R., 1978. Injuries to runners. American Journal of Sports Medicine 6, 40–50

Daniel E. Lieberman, Madhusudhan Venkadesan1, William A. Werbel, Adam I. Daoud, Susan D’Andrea, Irene S. Davis, Robert Ojiambo Mang’Eni & Yannis Pitsiladis; Foot strike patterns and collision forces in habitually barefoot versus shod runners; Nature 463:531-5

Berlucchi, Giovanni, and Salvatore M Aglioti. "The Body in the Brain Revisited." Experimental brain research. Experimentelle Hirnforschung. Expérimentation cérébrale 200, no. 1 (2010): doi:10.1007/s00221-009-1970-7.

Fuentes, Christina T, and Amy J Bastian. "Where Is Your Arm? Variations in Proprioception Across Space and Tasks." Journal of neurophysiology 103, no. 1 (2010): doi:10.1152/jn.00494.2009.

Bramble, DM and Lieberman, DE (2004) Endurance Running and the Evolvolution of Homo. Nature 432: 345-352.