The energy boost running shoes from Adidas came to the market a few years ago to mixed commentary. Adidas were cautious what they claimed about the shoe, but bench testing did show the the material did provide a better ‘energy return’ than a typical running shoe material. Did that translate to better running economy? At that stage we did not know as the work had not been done, yet somehow the fan boys did claim that it doesn’t – I am intrigued to know how they actually knew that as no one had done the work. They were just making it up and hoping it was true (the wishful thinking fallacy). Since the shoe launch we had the Worobets et al study last year that showed running in softer shoes were more economical and the Tung et al study from 2013 that appears to show that a softer shoes would be more economical, but probably showed that the response to softer shoes on running economy is subject specific. Now we have a study that specifically looked at running economy in the Adidas Energy Boost compared to the Saucony Pro Grid Guide:
Influence of footwear designed to boost energy return on running economy in comparison to a conventional running shoe
J. Sinclair, R. Mcgrath, O. Brook, P. J. Taylor & S. Dillon
Journal of Sports Sciences in press
Running economy is a reflection of the amount of inspired oxygen required to maintain a given velocity and is considered a determining factor for running performance. Athletic footwear has been advocated as a mechanism by which running economy can be enhanced. New commercially available footwear has been developed in order to increase energy return, although their efficacy has not been investigated. This study aimed to examine the effects of energy return footwear on running economy in relation to conventional running shoes. Twelve male runners completed 6-min steady-state runs in conventional and energy return footwear. Overall, oxygen consumption (VO2), heart rate, respiratory exchange ratio, shoe comfort and rating of perceived exertion were assessed. Moreover, participants subjectively indicated which shoe condition they preferred for running. Differences in shoe comfort and physiological parameters were examined using Wilcoxon signed-rank tests, whilst shoe preferences were tested using a chi-square analysis. The results showed that VO2 and respiratory exchange ratio were significantly lower, and shoe comfort was significantly greater, in the energy return footwear. Given the relationship between running economy and running performance, these observations indicate that the energy return footwear may be associated with enhanced running performance in comparison to conventional shoes.
Nothing in the methods and the analysis jumps out at me as being problematic. An issue may be the design features that are different between the two shoes used, in that they differ on other characteristics than just the midsole material.
They concluded that:
In conclusion, the current investigation provides new information describing the influence of commercially available footwear, claimed to increase energy return on the economy of running. On the basis that decreased VO2 and RER were observed when running in the footwear which aims to increase energy return, the current investigation suggests that these new footwear may be associated with increases in running performance. This study indicates that runners interested in performance may wish to select the energy return footwear over more conventional shoe models.
The worlds fastest 5 marathons have been run in one of these shoes. There is a reason for that.
As always, I go where the evidence takes me.
Sinclair, J., Mcgrath, R., Brook, O., Taylor, P., & Dillon, S. (2015). Influence of footwear designed to boost energy return on running economy in comparison to a conventional running shoe Journal of Sports Sciences, 1-5 DOI: 10.1080/02640414.2015.1088961