Expository Synthesis: Minimalist Running Shoes and Mechanics

Minimalist 1

Brother Grover

March 4, 2016

Introduction

In his article, “Six Years Later: The Legacy of ‘Born to Run,’” Brian Metzler addresses the impact of Christopher McDougall’s 2009 book, “Born to Run: A Hidden Tribe, Superathletes, and the Greatest Race the World Has Never Seen.” Metzler lists one of the most influential and lasting effects of the book as follows:

The book was one of the primary catalysts for the minimalist running shoe revolution that helped spur brands to develop lighter, lower-to-the-ground shoes using less material. While some would argue that “barely there” shoes led many runners to run with insufficient cushioning and protection under their feet, there’s no question the paradigm shift helped runners rethink about how much (and how little) they really need in a shoe (Metzler, 2014).

The effectiveness and feasibility of minimalist shoes has been a hotly debated topic over the course of the past decade. One of the primarily disputed claims made by advocates of the minimalist shoe is that it improves the running mechanics of the wearer. This paper will expound upon the current state of research concerning whether or not minimalist running shoes do indeed improve a runner’s mechanics, and by extension, reduce injury rates.

Background

The book, “Born to Run,” gained acclaimas it challenged the long standing belief held by many runners, and the industry in general, that a running shoe was meant to correct certain aspects of a runner’s form. The traditional running shoe incorporated things like “increased cushioning, elevated heel, as well as motion control and stability technologies” (Esculier, Dubois, Dionne, Leblond, Roy, 2015). Much of the intent of these devices was to reduce the occurrence of injury for runners. McDougall argued that this approach was ineffective and potentially even harmful. He became a strong contributor to the minimalist running movement, which trumpeted the body’s natural form and ability (Parks, 2010).

As the minimalist movement began to garner wider acceptance runners started to defy convention and began experimenting with lighter and more flexible shoes. “Many runners who were told to wear stiff, heavy, motion-control shoes have felt liberated (and remained injury-free) by moving to barely there shoes that allow their feet to work naturally” (Douglas, 2013). This transition has sparked debate as to whether or not minimalist shoes may in fact be the cure to several of the common runner’s ills. Research has been conducted on a variety of topics associated with minimalism in order to determine whether there is any significance to the claim that a reduction in motion-control devices improves a runner’s form and their ability to remain free of injury.

Concept and Design

The first step to evaluating the effectiveness of minimalist footwear is to understand the underlying concept. The theory is that while running barefoot a runner’s body naturally moves in such a way as to minimalize impact forces. Such adaptations include a shorter stride length, a tendency to land more on the forefoot or midfoot rather than the heel, and a higher turnover rate that result in decreased contact time with the ground. The purpose of a minimalist shoe is to facilitate the gains of barefoot running while also providing some additional protection for the foot itself.

While the purpose of minimalist shoes is quite straightforward, the application is more difficult to interpret. At what point does a shoe gain the classification of “minimalist?” In 2015, a panel of 42 experts from 11 countries attempted to outline a grading scale for minimalist shoes. The result was an index based on the following definition of minimalist shoes: "Footwear providing minimal interference with the natural movement of the foot due to its high flexibility, low heel to toe drop, weight and stack height, and the absence of motion control and stability devices” (Esculier et al., 2015).This scale, known as the “Minimalist Index” awards points based on a shoe’s adherence to a standard of measurements in each of the aforementioned categories. The maximum score, and therefore the ideal representation of “minimalist,” is achieved at 100 points. Establishing a definition of “minimalist” in this way allows researchers to evaluate each characteristic of a shoe and its effect on a runner’s movements.

Effect on Mechanics

After understanding the theory that minimalist shoes are able to replicate the inherent characteristics of barefoot running one must discover whether the results remain true in practice. Many studies and surveys have been conducted that focus on the movements of the runner’s body in relation to their type of shoes, or lack thereof. Footstrike is oneof the leading topics of such research, with the prevailing belief that a more forward or midfoot strike is superior to landing at the back of the foot. An online survey of over 1000 male and female experienced runners reported that, “Shoe selection was significantly associated with reported footstrike. Barefoot and minimalist runners reported a more anterior footstrike than traditionally shod runners” (Goss, Gross, 2012). This data appears to support the conclusion that minimalist shoes do in fact resemble barefoot running in terms of footstrike patterns.

While footstrike may be similar between running barefoot or in minimalist shoes, other mechanical aspects may not find the same common ground. A particular study that refuted proposed similarities between the two running conditions was titled “Running in a minimalist and lightweight shoe is not the same as running barefoot: a biomechanical study.” In this example researchers recruited a group of highly trained runners which they tested running barefoot, in minimalist shoes, racing flats, and the athlete’s normal training shoe. They found that, “There were significant differences between barefoot and shod conditions for kinematic and kinetic variables at the knee and ankle, with no differences between shod conditions” (Bonacci, Saunders, Hicks, Rantalainen, Vicenzino, Spratford, 2013). The study presented approximate percentages of variance in the range of motion in the joints of the knees and ankles with some results differing by as large as 24%. The study concluded that, “Barefoot running was different to all shod conditions. Barefoot running changes the amount of work done at the knee and ankle joints and this may have therapeutic and performance implications for runners” (Bonacci et al., 2013).

Injury Prevention

In 2012 Carey Rothschild published the results of a survey that was meant to “investigate runners' interest, participation and use of barefoot or minimalist shoe running” (Rothschild, 2012). Included in the survey were the responses of 6,082 runners. Researchers found that approximately 10% of all runners surveyed expressed interest in running barefoot or in minimalist shoes. Interestingly, it was discovered that “the primary motive for running barefoot or in minimalist shoes was the prevention of injuries and that a fear of injuries was the most prevalent perceived barrier to barefoot running” (Rothschild, 2012).

In addition to the average runner, many professionals have questioned whether running in minimalist shoes may lower injury rates when compared with their “traditional” style counterparts. Returning to the results of the survey in which footstrike was discussed; information was also collected on injury rates among surveyed runners. “Traditionally shod runners were 3.41 times more likely to report injuries than experienced minimalist shoe wearers. Minimalist shoe wearers also reported fewer injuries at the hip, knee, lower leg, ankle, and foot than traditionally shod runners”(Goss, Gross, 2012). The results of this survey suggest that there is a very real correlation between the type of shoe and both the rate and location of injury.

For every study or survey that points to a relationship between minimalist shoes and declining injury rates there seems to be an equally compelling argument in opposition. The online site for the Human Performance Research Center, a Department of Defense initiative meant to keep America’s fighting force healthy and strong, had this to say about minimalist running shoes, abbreviated “MRS:”

Does minimalist running translate to lower injury rates? While advocates for MRS suggest that landing mid-foot (which MRS seems to promote) disperses collision forces and may improve running economy, the truth is that there are no objective scientific studies to show that minimalist-style running or MRS reduce the risk for injuries. One comparison of minimalist to traditional running shoes found no difference in running mechanics between wearers of the two types of shoes. In fact, while other injuries may be lower among barefoot and minimalist runners, they might be at increased risk for forefoot and mid-foot injuries such as stress fractures and plantar fascia injuries. (“Minimalist running”)

Indeed, as indicated by the Human Performance Research Center, there does not appear to be any definitive evidence as to the ability of minimalist style running shoes to reduce the risk of injury to the wearer. The field has demonstrated promise though, and many experts agree that more research is needed to come to any lasting conclusion on the subject.

Future Outlook

What is the future of the minimalist running shoe and its proposed benefits? An article in the popular magazine, Runner’s World, seeks to answer that very question. The author describes that the perception of minimalist shoes is changing. Speaking in regards to one of the most iconic minimalist shoe companies and their signature product, he states, “a spring 2012 proposed class-action lawsuit against Vibram for false advertising claims that the FiveFingers shoe reduces injury and improves posture and foot health certainly symbolized a potential end of the love affair with the less-is-always-better approach” (Douglas, 2013). This statement supports what has already been discussed about conflicting opinions on how minimalist shoes affect the health and motion of a runner. The article does not end there though, with the fading of the minimalist shoe seeming imminent. In fact, the author seems to prove quite the opposite. The author quotes an interview with RunningWarehouse.com’s Joe Rubio, “‘I think the movement toward lighter and faster and more responsive isn't going to end,’ says Rubio. ‘It's just going to be a natural part of shoe development’” (Douglas, 2013).

Conclusion

In conclusion, experts have yet to reach a consensus on the overall effectiveness of minimalist shoes. Evidence is found both for and against the notion that minimalist running shoes positively influence the mechanics of the wearer. The incongruent results are often attributed to the physiological differences in people themselves, suggesting that there may not be any one “perfect fit.” Additionally, researchers have pointed out inconsistencies in the way that studies concerning minimalist running are being conducted. It is a generally accepted belief that significantly more research and study is warranted.

Despite lack of definitive evidence in favor of minimalist running shoes almost all parties recognize the contribution that the minimalist movement has made in causing the running industry to reevaluate the characteristics of the ideal running shoe. The progression of research into how human mechanics are affected by shoe characteristics is anticipated to yield future innovations that will continue to change the industry.

References

Bonacci, J., Saunders, P. U., Hicks, A., Rantalainen, T., Vicenzino, B. T., Spratford, W. (2013, April). Running in a minimalist and lightweight shoe is not the same as running barefoot: a biomechanical study. British Journal of Sports Medicine. 47(6), 1-6. DOI: 10.1136/bjsports-2012-091837

Douglas, Scott (2013, March). Minimalism in the Long Run. Runner’s World. Retrieved from

Esculier, J., Dubois, B., Dionne, C.E., Leblond, J., Roy, J. (2015). A consensus definition and rating scale for minimalist shoes. Journal of Foot and Ankle Research.DOI: 10.1186/s13047-015-0094-5. Retrieved from

Goss, D. L., Gross, M. T. (2012, October-December). Relationships Among Self-reported Shoe Type, Footstrike Pattern, and Injury Incidence. U.S. Army Medical Department Journal. 6, 25-30. Retrieved from

Metzler, Brian. (2014). Six Years Later: The Legacy of ‘Born to Run.’ Competitor. Retrieved from

Minimalist running shoes revisited. Human Performance Research Center. Retrieved from

Parks, Bob (2010, October). Is Less More? Runner’s World. Retrieved from

Rothschild, Carey E. (2012, August). Primitive Running: A Survey Analysis of Runners' Interest, Participation, and Implementation.Journal of Strength & Conditioning Research. 26(8), 2021-2026. Retrieved from