Dr Joel Fuller is a physiotherapist, who has just submitted his PhD thesis in sports science at the University of South Australia. JetSetGo personal trainer, Sarah Bray, recently met up with Joel to find out more about his exciting research investigating the effects of transitioning from conventional running shoes to more minimalist, lightweight racing flats.

Around 10% of Australians like to run to improve their health and fitness, or even for the pure fun of it. Which running shoes to buy is a dilemma faced by many recreational runners. Are the more expensive ones really better? Do the flashy big brand name ones help you run faster? Do more cushioned, conventional shoes reduce risk of injury? Or do more lightweight minimalist shoes allow you to run more efficiently? There’s also the almost romanticised idea popularised in books such as Chris McDougall’s “Born to Run”, that more minimalist or even bare-foot running is what we were evolved to be doing, and that ‘over-protective’ modern conventional shoes cause more problems than they prevent. There’s a lot of questions, and a lack of high-quality scientific evidence to help us address them.

img_0762-gel-cumulus-copy
Asics Gel Cumulus

Summary of the research study: You can watch Joel’s Three Minute Thesis video overview of the research study here, but if you would like a bit more of the technical details, keep reading. This was the first randomised control trial to investigate the effects of gradually transitioning to minimalist footwear over a 6-month period, looking at injury risks as well as running performance1. A previous study2 conducted in Canada did also look at injury risks during a 3-month transition to partial-minimalist or minimalist shoes, but did not assess running performance. Half the participants were given conventional running shoes (Asics Gel Cumulus) the other half were given minimalist lightweight racing flats (Asics Piranha). The participants were instructed to complete only 5% of their running in their allocated test shoes on each day that they ran in the first week, and this amount would then be increased by an additional 5% each week until week 20 when 100% of their running would be performed in the test shoe. Their training program included both long slow distance running and high-intensity interval training (HIIT). Pain was assessed with a study diary to record any pain the participants experienced, this was scored against a scale for 7 sites of interest (including ankle, shin, knee, foot, calf). Any musculoskeletal problem participants attributed to their running (rather than an unrelated accident), that resulted in a decrease in weekly running volume, the use of medication or a visit to a health professional was considered as an ‘injury’. Runners were also

Asics Piranha img_1076
Asics Piranha

assessed for running biomechanics, muscle strength, bone mineral density and with 5km time trial tests on a treadmill.

Limitations of the study: As with most clinical trials, variables must be controlled so that it is possible to draw meaningful conclusions from the results without confounding effects confusing or diluting the significance of the findings. In this study, all participants were males aged 18-40 years old, and were regular runners who were able to run a minimum of 15km per week. They were assessed as rear foot/heel strikers (rather than fore-foot strikers – as one of the proposed benefits of swapping to minimalist shoes is that it is thought to increase fore-foot landing), but they were not specifically assessed for over-pronation vs neutral running styles. Therefore, it is not possible to say whether the results will hold true for female runners, or whether if a runner has a pre-existing issue such as over-pronating if this might increase risk of injury when transitioning from a more supportive, cushioned conventional shoe to a minimalist one compared to a neutral runner in conventional shoes.

Take home results from the study so far after talking to Joel:

  • If you weigh less than 72kg, transitioning gradually to minimalist shoes can result in increased running performance without increased risk of injury compared to running in conventional shoes.
  • If transitioning to minimalist shoes, this should be done gradually to reduce the risk of injury associated with sudden changes in footwear (no more than increases of 5% per run per week in the minimalist shoes).
  • If you weigh 72kg or more (irrespective of how physically fit you are), transitioning to minimalist shoes (even gradually) is associated with increased risk of injury.
  • If you weigh >85kg, the risk of injury is increased by 3-fold if you swap to minimalist shoes, compared to sticking with conventional shoes.
  • These weight thresholds appear to be an absolute mass effect rather than relating to physical fitness or BMI. So even if you weigh less than 72kg, if you run with a pack that takes you over that weight threshold, your risk of injury is likely to increase.

Funny story from the study: One of the questions I asked Joel was about the logistics of only running 5% of each run in the minimalist shoes, and then gradually increasing this proportion of the run in minimalist shoes each week. One of the reasons so many people develop injuries when they transition to minimalist shoes is thought to be because they transition too quickly for their body to adapt to the different stressors associated with running in the different shoes, which is why this study insisted on such a strict and gradual transition. Apparently the trial participants had lots of creative ideas to overcome the logistic issues…some would set out on a shorter loop in the minimalist shoes, return to their home/workplace, swap shoes and then continue for the rest of their run in the conventional ones. Others had friends or partners meet them along their route to swap shoes…and the one I like the most (partly because it sounds like a Monty Python skit) – some apparently hid their second pair of shoes in the bushes somewhere along their planned route!!  It just goes to show, if you want to take the leap and try minimalist running shoes, it’s not a decision to be taken lightly, it’s going to require some dedication and patience to gradually and safely transition in 5% increments per week!

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Joel has submitted his PhD for examination, and the initial results of this trial have also been submitted for publication (I’ll insert a link to the article once it has been published). JetSetGo Fitness wishes him all the best for the outcome of his PhD thesis, and for all his future research endeavours.

I would also like to thank Mario from Joggers World for letting me take photos of the styles of shoes used in Joel’s study. If you are looking for a new pair of running shoes, I have always found the staff at Joggers World in Adelaide’s CBD are very patient and helpful at finding the right shoes for you.

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References:

  1. For those who would like more detail, the trial design has been published and can be found online: Fuller JT, Thewis D, Tsiros MD, Brown NAT, Buckley JD. “The long-term effect of minimalist shoes on running performance and injury: design of a randomised controlled trial”. BMJ Open 2015; 5:e008307 http://bmjopen.bmj.com/content/5/8/e008307.full
  2. The abstract of the previous Canadian study can also be found on PubMed: Ryan M, Elashi M, Newsham-West R, Taunton J. “Examining injury risk and pain perception in runners using minimalist footwear”. British Journal of Sports Medicine 2014; 48(16):1257-62. https://www.ncbi.nlm.nih.gov/pubmed/24357642

 

2 Comments

  1. Amy

    Great to see there is finally some science emerging about this. Until an RCT of both genders is done, an N=1 study of myself supports the idea that the <72kg rule for positive outcomes with minimalist running shoes also applies to women :). I've been running in Vibram 5 finger shoes for 24 months, transitioning from relatively flat lace-up joggers. I found it helps to run on grass and stretch thoroughly (especially calves) and haven't had any major issues.

    • PT Sarah

      That’s great to hear Amy! Although as you say, we wont know until a proper trial is done for women, so far anecdotal evidence from women like yourself that I have spoken to seems consistent with Joel’s findings regarding the 72 kg threshold. Obviously a (very) small sample size, but the few women who have told me they transitioned gradually to minimalist style running shoes successfully without experiencing injury, and now swear by them, are all under 72 kg.

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