Carbon Plates: Performance Enhancing or Injury Inducing

As studies on super shoes come out, two different ideologies have formed. One group believes that super shoes increase injury risk over time, but the other group believes the complete opposite. They point to the reduced stress and improved ability to handle training load, to show that shoes with a carbon plate reduce injury risk. 

An article in the MIT Technology Review considers this exact position. They interview David Kirui, a physical therapist that treats many of Kenya’s top marathon runners. He estimated that overuse injuries were down by around 25% due to the increased use of super shoes. His ideology was supported by Jonathan Maiyo, an experienced racer and elite road runner since 2007, who said that “in the old shoes, after 10 marathons you’d be completely exhausted.” He sees a huge change in this and now says that “10 marathons are like nothing.” The group of Kenyans coach Claudio Berardelli estimated that his athletes do at least 60% of their mileage in super shoes. 

Kenyan distance runners subscribe to the high mileage strategy completely. Weekly mileage for world class marathon runners like the group mentioned is often around 220 kilometers or about 137 miles. The late Kelvin Kiptum who had a meteoric rise to prominence reportedly had a regular mileage of 280 kilometers or about 173 miles a week. That equates to 24 miles a day and is clearly high mileage. If the group interviewed ran the estimate of 137 miles and we take the low estimate of 60% of mileage in super shoes, it would tell us that they run around 80 miles a week in carbon plated shoes. 

It would make sense if, because of the high volume, these athletes saw an increase in injuries over time. There are a few different reasons I think we don’t see this. First is the reduction of stress professional athletes see when they go pro. Especially in Kenya athletes are often doing a huge training volume without proper equipment before they go pro. Kelvin Kiptum is a prime example of this. Before he became one of the most well known marathon runners in the world, he was doing his training barefoot. While there have been some documented benefits to training barefoot, it is widely known that high mileage barefoot is unsustainable. When he went pro it can be reasonably assumed that there was a huge reduction in musculoskeletal stress for the same amount of training. A similar reduction should be found when super shoes are introduced. The difference is that over time the redistribution of load increases the risk. 

Another reason we don’t see this increase in that group in particular could be the other training they do. Their exact training is unknown because different teams hide their training to avoid copycats cropping up, but it should include strengthening outside of running. If their coach, who has a background in sports science, is smart he can adjust their strengthening regimen to strengthen the regions necessary before it becomes an issue. If the area the load is redistributed to is already strong then an injury is far less likely to occur. This wouldn’t show up in most studies because the average person doesn’t have a coach that does that. Even most coached athletes don’t have a coach that is able to do that. That kind of training needs to be backed by a coach that knows the athlete well. Super shoes are a mass market product that are marketed to everyone. The problem is still there even if careful training outside of running can mitigate the additional risks.

The third reason that the group doesn’t see the increase in injuries predicted by studies is the difference in the individual. While the study done by the Department of Sport and Exercise Science at the University of Salzburg and the Red Bull Athlete Performance Center in Austria, showed an example of an athlete responding poorly it’s possible that this group is an example of a group that responds well to the shoes. 

The MIT article mentions individualism when it comes to performance but it holds true for health too. They look to a study done by Wouter Hoogkamer that revealed a 4% range in performance improvement. Hoogkamer also commented on why he believes athletes respond so differently to super shoes. He thought there were around 20 variables affecting the response to the shoes including weight, calf strength, and the strike pattern of the runner. The strike pattern of an athlete is usually categorized into forefoot, midfoot, and rearfoot with the location being the first point of contact between the foot and the ground. While it can be broadly categorized into those three categories there are countless other subcategories including the natural level of eversion and inversion on impact. 

Abdi Nageeye, a Dutch marathon runner that finished second in the Tokyo Olympic marathon and won the 2024 New York City marathon earlier this month, is a heel striker. He struggled significantly with the first two versions of the Nike Alphafly because they forced his stride into a different pattern that felt unnatural. He described the change as a “skip” in his stride. In contrast to his struggles with the first two versions, the third version of the Alphafly worked well for him. He won his first ever major marathon in the shoes. As a Nike athlete the Alphafly was what he had to race in even when his stride was being changed unnaturally. Changes in form increase injury risk and could have caused injuries. 

Small case studies like these have huge variation. Just like the variation in the shoes performance the variation in the effect on the runner is large. Studies with large sample sizes help to even this out. There are more and more studies coming out with results that point towards increased injury risk. Alone there isn’t a study that proves the argument one way or the other. There are case studies going both ways. Put together the scientific studies only point one way. They point towards increases in injury over time and the potential for long term problems. 

References

Supershoes are reshaping distance running. (n.d.). MIT Technology Review. https://www.technologyreview.com/2024/06/25/1093520/supershoes-running-kenya-carbon-plate-shoes/ 

‌Hobson, B. (2023, May 31). Meet the coach, Claudio Berardelli. Runner’s World. https://www.runnersworld.com/uk/training/a43781904/claudio-berardelli/ 

Moore, S., Martinez, A., Schwameder, H., & Stoggl, T. (2023, July 12). THE MEDIOLATERAL CENTER OF PRESSURE MOVEMENT DIFFERS BETWEEN TRAINING AND RACING SHOES: A CASE STUDY [Review of THE MEDIOLATERAL CENTER OF PRESSURE MOVEMENT DIFFERS BETWEEN TRAINING AND RACING SHOES: A CASE STUDY]. Department of Sport and Exercise Science, University of Salzburg, Austria Red Bull Athlete Performance Center, Thalgau, Austria. https://commons.nmu.edu/cgi/viewcontent.cgi?article=2665&context=isbs 

‌