Point-Counterpoint: Minimalist Running Shoes: A Significant Advance Or Injuries Waiting To Happen?

Author(s): 
Nicholas A. Campitelli, DPM, FACFAS, and Kevin A. Kirby, DPM

Significant advance.

Noting a lack of evidence support for traditional running shoes with elevated cushioned heels, this author says the wider toe box of minimalist shoes and a gradual transition of running form can be beneficial for runners.

By Nicholas A. Campitelli, DPM, FACFAS

To think a shoe could solve every runner’s problems with injuries is hard to believe yet that is what it has come to in our society. It is not just runners who have this perception. This belief seems to be pretty common in the general population as well. Most would not argue that when it comes to foot pain, the shoe is the first thing patients will look at to solve their problem.2

   The question that has arisen in the past several years is, “Do we really need a supportive shoe to run?” My answer is absolutely not. Having been on both sides of this argument, I feel I can offer an unbiased opinion. For 10 years, I suffered from sesamoiditis that did not respond to any shoe or orthotic that I wore. Only after I abandoned traditional running shoes and changed my running form was I able to resolve the issue.

   My problems with traditional running shoes are numerous. First, the shoes tend to have a large cushioned heel, which really serves no biomechanical purpose other than absorbing shock. In fact, a 2009 literature review of several electronic databases found that the prescription of running shoes with elevated cushioned heels and pronation control systems was not evidence-based.1 Consider that even when fitting a patient for an orthotic device, of all the angles and positions in which one places the foot and measures it, many physicians never consider the height of the shoe’s heel.

   Ankle equinus is a condition that often requires surgery to resolve the biomechanical issues it is creating. Yet what happens when one slips a foot into a traditional running shoe? The foot assumes a plantarflexed position in which it is expected to function when one is running. To give you an example, a heel height of 14 mm will place the foot of an individual with a size 9 shoe in 4 degrees of plantarflexion.

Rethinking Our Perceptions On Excessive Pronation

Traditional running shoes as a whole typically fall into three categories that are universal among the running shoe manufacturers. The shoes are supposedly created for individuals with arch types that are high, normal or flat. The rigidity and support will increase or decrease depending on the foot type and the theory that one will need to control or encourage excessive pronation.

   This running shoe paradigm does not take into account the runner’s form or foot strike pattern but only presumes he or she is heel striking. When you look at how a podiatrist interprets Root’s theories of biomechanics and how excessive pronation can lead to injury, it is only in regard to heel striking. If you convert that same foot type to a forefoot or midfoot strike, will the runner still experience excessive pronation or will the pronation that is occurring absorb the impact up until the point when the heel then strikes the ground?

   This is the controversial point. Does the definition of excessive pronation as has been discussed in regard to injury even exist if one lands with a forefoot or midfoot strike pattern?

Understanding The Premise Behind A Wider Toe Box

I think we can all agree that proprioception is a key component to all individuals’ gait. If we cannot feel the ground beneath our feet, then it becomes very difficult to recruit the lower extremity musculature adequately to respond to the terrain we are running on. This is where the toes play an important role.

   When one lands with a forefoot or midfoot strike pattern, the toes are splayed and extended in preparation for landing when they will grip the ground to allow for the rest of the foot to then lower slowly to the ground. The flexor hallucis longus, flexor digitorum longus, flexor hallucis brevis, flexor digitorum brevis, abductor hallucis and abductor digiti minimi all play a crucial role in this process. If the toes are not feeling the surface, this hinders proprioception, making the recruitment of the aforementioned musculature very inefficient. This is the premise of the wider toe box that minimalist shoes tend to have. The less constricted the digits are, the easier it is for them to function.

   Root describes the foot as a mobile adapter when the subtalar joint is allowing for pronation of the foot.2 If a rigid midsole component of the shoe is preventing the “mobile adaptation” from occurring, where does this stress or force go? I would hypothesize it transmits to the lower extremity where the legs muscles have to work harder to absorb the force. The rigid midsole component prevents the mobile adapter from working.3

How Does Overuse Factor Into Injuries Associated With Minimalist Shoes?

If you look at the recent literature published on injuries associated with minimalist shoes, you will find one common theme: overuse.4,5 Despite the argument that we need to address biomechanical deformities with the proper shoe or orthotic, recent case reports suggest that documented injuries in minimalist shoes may be due to overuse without adapting gradually to the shoe gear.4,5

   Early recommendations have emphasized a gradual transition by running with this new style for no more than 10 percent of your weekly mileage and building upon that weekly.6 The premise is that you are learning a new running style and the muscles need to adapt. Putting on a pair of minimalist shoes and running six miles for the first time would be not much different than a person who has never run before putting on a pair of traditional running shoes and running six miles. They both are at risk for stress fractures and overuse injuries.

When The Author Incorporated Minimalist Shoes Into His Practice

Before introducing this philosophy of “shoe gear” to my patients, I obviously spent time reviewing the literature to see what existed with respect to current recommendations for shoe gear as well as running. Surprisingly, I do not feel there is much to support the use of running shoes as we know them today. Were our feet meant to work without shoes or were they meant to work with shoes that support the foot and prevent the necessary motion that should be occurring? It is my observation that if you keep running form constant, shoes shouldn’t matter. Before the 1970s, we didn’t put as much emphasis on shoes. It seems to me that we try to correct running injuries with shoes and inserts (custom or prefabricated) instead of working on form and training patterns.

   At the same time, I had been suffering from sesamoiditis for 10 years that was not responding to orthotics or traditional running shoes. I have come to realize the condition had existed for 10 years not because of the shoes I was wearing but because of the form they were indirectly forcing me to run with. The form — running with an outstretched leg, accentuated heel strike and an upright vertically positioned body — was creating tremendous force on my forefoot.

   After gradually transitioning to a midfoot strike pattern while running on a treadmill in Vibram FiveFingers (given they were the only option for minimalist shoes at that time), I was able to resolve my sesamoiditis after six to eight weeks. I then began introducing the philosophy into my practice.

   Whenever I encountered runners who were not responding to orthotics, shoe gear changes and physical therapy treatments, I educated them on these principles. Obviously, there is more to a running injury than just the aforementioned treatments but my thinking was to introduce the patients to a natural form and make them realize how easily obtainable that form is when they are not in a shoe. I have been scrutinized for telling individuals to run barefoot as they may “step on glass or a rock” or even “cut their foot,” which misses the point. By running without shoes, it becomes very hard to run incorrectly. I realize that is a big assumption but taking long strides and heel striking barefoot becomes extremely difficult because it will hurt. I like to use the phrase “Shoes should allow you to run, not enable you to run.”

   Over the past two years, I have helped numerous runners who have been plagued with injuries that did not respond to conventional treatment. Why? It’s not the minimalist shoes directly, it is the gradual adaptation in running form that has been key in my experience.

Can Switching To Minimalist Shoes Help Address Recalcitrant Plantar Fasciitis?

Not only have I incorporated the minimalist shoe for runners but I have also instituted it as part of my regimen in treating recalcitrant plantar fasciitis. When patients present with plantar fasciitis that has not responded to conservative treatment over the timeframe of three to six months, I suggest to these patients to begin functioning barefoot at home in the house for 30 minutes a day and gradually increase the time weekly.

   In my experience, I have found that many times, individuals can benefit from changes to their shoe gear. Progressing to a flatter, more flexible shoe allows the foot to be parallel to the ground without compromising a natural gait.

   I teach patients with plantar fasciitis to avoid long strides and not accentuate a heel strike with the thick rubber heel attached to their shoe. Many times, the stride people carry, especially men, is a direct result of their shoe gear. Some patients are reluctant initially as they have been told not to go barefoot and that they need orthotic devices. While I agree that the use of orthotics is an acceptable treatment option for acute plantar fasciitis, I do not agree with it for chronic situations. It is also pretty evident if patients have been treating their plantar fasciitis for six months or more with cushioned shoes and orthotics with no success, it is not working.

In Conclusion

It has been said that minimalist shoes may work for some but not for everyone. This is partly true. I will say that the thinking among our profession, as well as our society, needs to shift from what we put on our feet to how our feet should be functioning and working as they were intended to.

   Dr. Campitelli is an Adjunct Professor at the Kent State College of Podiatric Medicine. He is in private practice at North East Ohio Medical Associates.

   Dr. Campitelli writes a monthly DPM Blog for Podiatry Today. To access the blog, visit http://www.podiatrytoday.com/blogs/1413 .

References
1. Richards CE, Magin PJ, Callister R. Is your prescription of distance running shoes evidence based? Br J Sports Med. 2009; 43(3):159-62.
2. Root ML, Weed JH, Sgarlato TE, et al. Axis of motion of the subtalar joint. JAPA. 1966; 56:149.
3. Kirby KA. Subtalar joint axis location and rotational equilibrium theory of foot function. J Am Podiatr Med Assoc. 2001; 91(1):465-87.
4. Cauthon DJ, Langer P, Coniglione TC. Minimalist shoe injuries: Three case reports. Foot (Edinb). 2013 May 10 (epub ahead of print) doi:pii: S0958-2592(13)00018-7. 10.1016/j.foot.2013.03.001.
5. Giuliani J, Masini B, Alitz C, Owens BD. Barefoot-simulating footwear associated with metatarsal stress injury in 2 runners. Orthopedics. 2011 7;34(7):e320-3.
6. Dreyer D. How to avoid injuries when transitioning to barefoot shoes or minimal running. Available at http://www.chirunning.com/blog/entry/how-to-avoid-injuries-when-transiti... . Published Nov. 23, 2011. Accessed July 30, 2013.

   For further reading, see “When Patients Ask About Barefoot Running And Minimalist Shoes” in the May 2013 issue of Podiatry Today.

Injuries waiting to happen.

This author notes that minimalist running shoes are not a new advance in shoe design and cites research that says these shoes may precipitate higher injury rates in runners.

By Kevin A. Kirby, DPM

The popularity of running has been gradually increasing ever since the early 1970s when the running boom began in America. Along with the rapid increase in running as a sport and fitness activity, the running shoe industry has also responded with a profusion of running shoe types and styles over the past four decades.

   One of the types of running shoes that has recently received considerable attention within the popular media is the minimalist running shoe. Minimalist running shoes are lighter in weight, have thinner soles, and have less difference in heel to forefoot shoe sole thickness (i.e. heel height differential) than do traditional running shoes.1

   The interest in minimalist running shoes was heightened with the publication of a 2009 book, Born to Run, by Christopher McDougall.2 In his book, McDougall claimed that thicker-soled running shoes with a large heel height differential are potentially harmful since they don’t allow runners to have a “natural” running form. McDougall claimed that running either barefoot or in thinner-soled minimalist running shoes would result in fewer injuries since our early ancestors ran barefoot.

   Many runners, caught up in their passionate desire to “run more naturally” after reading Born to Run, either began to run barefoot or run in a five-toed minimalist shoe, the FiveFingers™ shoe (Vibram), which was advertised to mimic barefoot running.2 Many of these runners, excited by the idea that it may be best or “more natural” to run barefoot or in minimalist shoes, even started to claim that the minimalist shoe was a new idea that would revolutionize the running shoe industry.

Why Minimalist Running Shoes Are Nothing New

However, contrary to the beliefs of many barefoot and minimalist running shoe advocates, the fact is that thin-soled, lightweight, low heel height differential running shoes are neither a new idea nor a new trend since these shoes have been continuously available in running shoe stores as racing flats ever since the 1970s. Runners routinely wore racing flats while racing or running speed workouts for years. I purchased my first pair of racing flats in 1972 while running as a sophomore for my high school cross-country team and I wore racing flats during my entire long-distance racing career for the next 20 years.

   In other words, these racing flats that myself and thousands of other distance runners wore from the 1970s onward had nearly identical shoe construction to today’s “minimalist running shoes.” Therefore, minimalist shoes represent simply a renaming of a four-decade-old running shoe type, not a radical new idea in running shoe design.

   Likewise, over 30 years ago, it was not uncommon for many collegiate long-distance runners, including myself and many of my college distance running teammates, to run workouts while barefoot as a way to vary the stress on our bodies during our intense workout and racing schedules. Therefore, the notion that running barefoot or running in “minimalist shoes” is a significant advance or is something new that just began a few years ago is not only a ridiculous idea but also fails to acknowledge the long history of barefoot running and the evolution of running shoe design within the distance running community over the past four decades.

A Closer Look At The Research

As a result of this misinformation that the barefoot running and minimalist shoe enthusiasts are promoting, it is very important for podiatrists to be knowledgeable of the research on minimalist running shoes in order to determine whether the claims that the minimalist running shoe advocates make are supported by the scientific literature.

   Ridge and colleagues recently conducted one of the best research studies to investigate the question of whether minimalist running shoes do indeed prevent running injuries.3 These researchers studied 36 experienced recreational runners split into two groups: a control group of 17 patients who ran in traditional thicker-soled running shoes and a minimalist shoe group of 19 patients who ran in Vibram FiveFingers minimalist running shoes for 10 weeks. The runners wearing FiveFingers shoes transitioned into these shoes using the same 10-week transition protocol that was published on the Vibram FiveFingers Web site in 2010.

   The runners in the study by Ridge and colleagues had magnetic resonance imaging (MRI) scans both before and after the 10-week period to monitor bone marrow edema and any other bone stress-related changes within their feet and ankles.3 Various authors have previously shown that MRI scans are able to detect bone stress injuries of the feet and ankles weeks before radiographs can detect any abnormalities.4-6 Even though pre-training MRI results were not statistically different between the two groups, the post-training MRI scores showed that more runners in the FiveFingers group (10 of 19) showed increases in bone marrow edema after 10 weeks of running than did the control group. In fact, of those who ran in the FiveFingers shoes, one of the runners developed a calcaneal stress fracture while another runner developed a second metatarsal stress fracture. No runners in the traditional running shoe group developed stress fractures during the 10-week training period.

   Within the medical literature, there are also reports of runners developing stress fractures and other injuries from running in minimalist running shoes. In a retrospective case series from Salzler and colleagues, 10 runners developed injuries when they switched from traditional running shoes to minimalist shoes.7 These injuries included eight metatarsal stress fractures, one calcaneal stress fracture and one plantar fascia rupture.

   In 2011, Giuliani and coworkers also reported two cases of second metatarsal stress fractures in experienced runners when they started running in Vibram FiveFingers shoes.8

   The increase in injuries that occurs with minimalist running shoes is possibly due to the more anterior foot strike, greater ankle plantarflexion moment in early stance, greater eccentric plantarflexion muscle involvement and greater impact peak loading rate found in people who run in minimalist shoes. Paquette and colleagues showed this in a recent study that compared the biomechanics of minimalist shoe running to traditional shoe running.9

Questioning The Claims Of A Minimalist Shoe Company

Possibly because these types of running injuries do occur, minimalist running shoe company Vibram now faces accusations, in two class-action suits, of falsely advertising the health benefit claims of their shoes.10,11 Vibram advertised that its FiveFingers minimalist shoes did the following:

• strengthen muscles in the feet and lower legs;
• improve range of motion in ankles, feet and toes;
• stimulate neural function, improving balance and agility; and
• align the spine and improve posture.

   To date, there is no scientific research that supports any of the advertised health claims of Vibram. In addition, possibly because of the difficulty people have transitioning to running in the FiveFingers running shoe, Vibram offers a 13-page “step-by-step guide” to shoe owners on how to run in their FiveFingers shoes without getting injured.12 No other shoe company in history has needed to provide its customers with such an extensive manual to prevent them from getting injured.

In Conclusion

“Minimalist running shoes” are neither a new idea nor a significant advance forward for runners since thin-soled, lightweight, low heel height differential running shoes have been continuously available as racing flats for years. In addition, a review of the available medical literature reveals no data that supports the notion that minimalist running shoes prevent injuries. Rather, the available research seems to support the fact that minimalist running shoes may lead to increased injury rates in runners.

   Even though the available scientific research is still unclear as to which type of running shoe will produce the fewest running injuries for each individual runner, what is clear is that the claims made by the barefoot and minimalist running shoe enthusiasts that wearing minimalist running shoes protects the runner from injury, at this time, seem to be highly improbable.

   Dr. Kirby is an Adjunct Associate Professor in the Department of Applied Biomechanics at the California School of Podiatric Medicine at Samuel Merritt University.

References
1. Kirby KA. Foot and Lower Extremity Biomechanics: A Ten Year Collection of Precision Intricast Newsletters. Precision Intricast, Inc., Payson, AZ, 1997, pp. 87-89.
2 McDougall C. Born To Run: A Hidden Tribe, Superathletes, And The Greatest Race The World Has Never Seen. Random House, New York, 2009.
3. Ridge ST, Johnson AW, Mitchell UH, et al. Foot bone marrow edema after 10-week transition to minimalist running shoes. Med Sci Sports Exerc, Epub ahead of print, Feb. 22, 2013.
4. Deutsch AL, Coel MN, Mink JH. Imaging of stress injuries to bone. Radiography,scintigraphy, and MR imaging. Clin Sports Med. 1997; 16(2):275-90.
5. Kiuru MJ, Pihlajamaki HK, Hietanen HJ, Ahovuo JA. MR imaging, bone scintigraphy, and radiography in bone stress injuries of the pelvis and the lower extremity. Acta Radiol. 2002; 43(2):207-1.
6. Spitz DJ, Newberg AH. Imaging of stress fractures in the athlete. Radiol Clin North Am. 2002; 40(2):313-31.
7. Salzler MJ, Bluman EM, Noonan S, et al. Injuries observed in minimalist runners. Foot Ankle Intl. 2012; 33(4):262-266.
8. Giuliani J, Masini B, Alitz C, Owens BO. Barefoot-simulating footwear associated with metatarsal stress injury in 2 runners. Orthopedics. 2011; 34(7):e320-e323.
9. Paquette MR, Zhang S, Baumgartner LD. Acute effects of barefoot, minimal shoes and running shoes on lower limb mechanics in rear and forefoot strike runners. Footwear Science, 5(1):9–18, 2013.
10. Available at http://www.invisibleshoe.com/vibram-complaint.pdf .
11. Available at http://www.courthousenews.com/2012/07/11/FiveFingers.pdf .
12. Available at http://s3.amazonaws.com/VibramFiveFingers/Barefoot_Running_Brochure_R13_...

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