Several previous prospective randomized studies have looked at injury rates between those using the traditional running shoes and barefoot/minimalist running shoes. I reviewed two here and here and did not review this one. I won’t relitigate the issues surrounding the claims regarding injury rates as I commented on that in those posts. However, the conclusions are all the same. The injury rates are higher in those using minimalist or barefoot running shoes or there is no difference between the two. This is not cherry picking studies as these are the only prospective studies done on the topic (and also the conclusion of all the systematic reviews on the topic of different study designs). Now we have this study just published:
Body Mass and Weekly Training Distance Influence the Pain and Injuries Experienced by Runners Using Minimalist Shoes
A Randomized Controlled Trial
Joel T. Fuller, BSc, Dominic Thewlis, PhD, Jonathan D. Buckley, PhD, Nicholas A.T. Brown, PhD, Joseph Hamill, PhD, Margarita D. Tsiros, PhD
The American Journal of Sports Medicine; 27 January
Minimalist shoes have been popularized as a safe alternative to conventional running shoes. However, a paucity of research is available investigating the longer-term safety of minimalist shoes.
To compare running-related pain and injury between minimalist and conventional shoes in trained runners and to investigate interactions between shoe type, body mass, and weekly training distance.
Randomized clinical trial; Level of evidence, 2.
Sixty-one trained, habitual rearfoot footfall runners (mean ± SD: body mass, 74.6 ± 9.3 kg; weekly training distance, 25 ± 14 km) were randomly allocated to either minimalist or conventional shoes. Runners gradually increased the time spent running in their allocated shoes over 26 weeks. Running-related pain intensity was measured weekly by use of 100-mm visual analog scales. Time to first running-related injury was also assessed.
Interactions were found between shoe type and weekly training distance for weekly running-related pain; greater pain was experienced with minimalist shoes (P < .05), and clinically meaningful increases (>10 mm) were noted when the weekly training distance was more than 35 km/wk. Eleven of 30 runners sustained an injury in conventional shoes compared with 16 of 31 runners in minimalist shoes (hazard ratio, 1.64; 95% confidence interval, 0.63-4.27; P = .31). A shoe × body mass interaction was found for time to first running-related injury (P = .01). For runners using minimalist shoes, relative to runners using conventional shoes, the risk of sustaining an injury became more likely with increasing body mass above 71.4 kg, and the risk was moderately increased (hazard ratio, 2.00; 95% confidence interval, 1.10-3.66; P = .02) for runners using minimalist shoes who had a body mass of 85.7 kg.
Runners should limit weekly training distance in minimalist shoes to avoid running-related pain. Heavier runners are at greater risk of injury when running in minimalist shoes.
Looking through the full paper nothing jumps out at me as problematic, except perhaps the sample size – it is down the lower end of being acceptable, but certainly not low enough to dismiss the results. Fan boys who don’t like the results might quibble over minor issues such as the adequacy of the transition to the minimalist running shoes. I have no issue and it was well within the guidelines that are widely advocating for the transition. The two shoes used were the Asics Gel Cumulus and the Asics Piranha. The Minimalist Index of the Cumulus is 72 and the Piranha is a 12, so there is an adequate difference between the shoes.
The other key finding with the study was the higher risk in those who are heavier, which certainly makes sense.
Going back, a lot of claims were made for the benefits of running in minimalist running shoes that have now clearly not been supported by the evidence. There is a reason that sales of minimalist running shoes have now fallen to 0.3% of the market.
As always, I go where the evidence takes me until convinced otherwise …. and evidence on this topic is becoming more obvious and consistent.
Fuller, J., Thewlis, D., Buckley, J., Brown, N., Hamill, J., & Tsiros, M. (2017). Body Mass and Weekly Training Distance Influence the Pain and Injuries Experienced by Runners Using Minimalist Shoes The American Journal of Sports Medicine DOI: 10.1177/0363546516682497