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Barefoot and minimalist: are they equivalent? ~ Jason Bonacci, PhD

Musculoskeletal overuse injury is highly prevalent in distance runners[1, 2].  The management of these overuse injuries often includes training advice, footwear prescription and running technique analysis.  Footwear prescription is an important component of the rehabilitation program as shoes can alter muscle activity and the kinematics and kinetics of the lower limb during running[3, 4], thereby influencing loading experienced with each foot strike.

Photo by Chris Hunkeler. Used with permission. All rights reserved. Source: flickr

Photo by Chris Hunkeler. Used with permission. All rights reserved. Source: flickr

Clinicians often prescribe footwear on the basis of foot type and categories provided by shoe manufacturers; such as “cushioning” and “motion control”. More recently, shoe manufactures have developed a new category of footwear termed “minimalist”. The idea is that these shoes provide the least interference to the natural running pattern as possible, whilst still providing foot protection. Manufacturers claim these minimalist designs provide the “benefits of training barefoot” or promote “barefoot running form.”

Despite the claims it is not known if these minimalist shoes can replicate the natural running pattern that occurs when running barefoot. Putting aside the argument of which is best (barefoot v shod), the clinician has very little evidence-based information upon which to form a basis for prescription of these shoes. Our recent study tested the hypothesis that running in a minimalist shoe is similar to running barefoot[5].

We undertook a three-dimensional overground running analysis of 22 highly trained runners in four different conditions:

  • their normal running shoes;
  • barefoot;
  • racing flats; and
  • minimalist shoes (Nike Free 3.0).

The participants performed ten running trials in each condition at a velocity of 4.48 m/s along an indoor synthetic running track. Our results revealed that the dynamics of running in a minimalist shoe were more similar to that of the other test shoes than running barefoot. In other words, the notion that running in a minimalist shoe is similar to running barefoot was not supported by the results of our study.

Running barefoot resulted in a flatter foot placement at foot strike, smaller knee flexion angles at midstance, lesser joint moments and work done at the knee and greater joint moments and work done at the ankle. These variables were different to all shod conditions, but similar between shod conditions, suggesting that the minimalist shoe acted more like a shoe than a barefoot condition.

When running barefoot there was a 24 percent decrease in negative work done at the knee and 19 percent increase in positive work done at the ankle in comparison to shod running. Clinicians should consider the potential therapeutic and performance implications of these loading changes if prescribing barefoot running for their athletes.

We readily acknowledge that there are minimalist shoes that are much more minimal than the Nike Free utilised in our study.  The Nike Free has an elevated heel and considerable cushioning which is not present in all minimalist shoes. However, this shoe clearly sits in the market as a minimalist shoe and is sold in very high volume (accounts for over 50 percent of sales in the minimalist category in Australia).

A more recent study[6] compared the lower limb running mechanics when running barefoot and in a more minimalist shoe (Vibram Fivefingers) than the Nike Free. That study found greater similarities between barefoot and minimalist shoe running, however there were still differences between the conditions. Specifically, ankle dorsiflexion kinematics and peak ankle plantarflexion moments and power were different between the minimalist shoe and barefoot running.

While this area of research is rapidly growing and we can expect to read more in this space, the evidence to date suggests that minimalist shoes cannot entirely replicate the dynamics of running barefoot. There are greater similarities between running barefoot and running in a minimalist shoe if that shoe is without cushioning and an elevated heel, but the idea that a shoe condition is the same as barefoot is not justified just yet.

Jason Bonacci holds an academic appointment in Anatomy and Biomechanics in the School of Exercise and Nutrition Sciences, Deakin University. He is also at Physiotherapist at Olympic Park Sports Medicine Centre in Geelong, Australia.

References

1 van Gent RN, Siem D, van Middelkoop M, et al. Incidence and determinants of lower extremity running injuries in long distance runners: a systematic review Br J Sports Med 2007;41:469-80.

2 Van Mechelen W. Running injuries – a review of the epidemiologic literature. Sports Med 1992;14:320-35.

3 Kerrigan C, Franz JR, Keenan G, et al. The effect of running shoes on lower extremity joint torques. Phys Med Rehabil 2009;1:1058-63.

4 Nigg B. Biomechanical considerations on barefoot movement and barefoot shoe concepts. Footwear Sci 2009;1:73-9.

5 Bonacci J, Saunders PU, Hicks A, et al. Running in a minimalist and lightweight shoe is not the same as running barefoot: a biomechanical study. Br J Sports Med 2013;47:387-92.

6 Paquette MR, Zhang S, Baumgartner L. Acute effects of brefoot, mnimal shoes and running shoes on lower limb mechanics in rear and forefoot strike runners. Footwear Sci 2013;5:9-18.

 

 

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