Super Shoes’ Impact on Non Elite Runners
by Doug Stewart
In the past I have written about a comparison between different carbon “super” shoes and the impact they had on runners’ economy. These findings revealed that on average, if running at 16kph, 2 of the carbon plated shoes assessed had no benefit versus standard running shoes. At the same time, the Nike Alphafly, Asics Metaspeed Sky and Nike Vaporfly 2 all improved economy by over 2.5%.
Now, the same lead author has taken the Nike Vaporfly 2 and done further testing at 10kph and 12kph in a newly published paper.
Similar in design to his previous research, a control, non-carbon plated shoe was used as a benchmark and then the Vaporfly were worn. 16 runners participated in the new study. They completed 4 x 5 min trials at 10kph and 12kph, wearing each shoe twice (some runners started in the control and switched to the Vaporfly, whilst others wore the Vaporfly first). The shoes were randomly assigned – so each athlete did not run in the same order of shoes. Ultimately, the researchers were trying to ensure that certain pairs of shoes or speeds were not always run when the athletes were at their most fresh or most fatigued.
The results showed that running economy at 12kph was on average 1.4% better in the Vaporflys versus the control shoe. At 10kph, there was still an improvement, but it had reduced to 0.9%.
Given the earlier research, where at 16kph the Vaporfly were showing an improvement of over 2.5%, it appears that the faster you run in the shoes, the greater the benefits on economy.
However, the impact on running speed is not linear with running economy. For example, a 4 hour 30 marathon runner having a 1% improvement in running economy would run 1.17% faster (saving 3 minutes and 7 seconds). An elite runner (2 hour 3 minutes marathon time), with the same 1% improvement in running economy, would see a .65% improvement on time (47 seconds). This is based on modelling by Kipp et al., (2019) and they suggest that, up until around 10.8kph, you will see a greater increase in running speed relative to running economy (like in the 4 hour 30 minute marathon runner example). However, once you get above that speed, the improvement in running speed will be smaller than the improvement in economy. For example, a 2 hour 4 minute marathon runner in shoes that improve economy by 3% would only see a speed improvement of 1.97%.
In conclusion, although you get less of an improvement in running economy as the speed decreases, the comparative improvement in running speed goes up… even if we’re only talking about tiny percentages!
References:
Joubert, D. P., Dominy, T. A., & Burns, G. T. (2023). Effects of Highly Cushioned and Resilient Racing Shoes on Running Economy at Slower Running Speeds. International Journal of Sports Physiology and Performance, 1(aop), 1-7.
Kipp, S., Kram, R., & Hoogkamer, W. (2019). Extrapolating metabolic savings in running: implications for performance predictions. Frontiers in physiology, 79.