Eliud Kipchoge's sub-two hour marathon time in Vienna has been the source of much back-and-forth commentary, specifically surrounding his shoes.
The unnamed model features unique chambers in the forefoot, and seems to be a prototype or variation of Nike's ZoomX Vaporfly NEXT%. What could potentially be a patent for the mystery shoe has been unearthed by Believe in the Run. A patent application was made by Nike in August 2018, for a “Stacked Cushioning Arrangement for Sole Structure.” The patent schematics appear to show cushioning apparatus that includes three plates (likely carbon fiber like the Vaporfly NEXT%), and four fluid-filled chambers. While it would be relatively safe to presume the main function of the fluid-filled chambers is cushioning, they could provide additional utilities like stability or energy return.
Governing body of 215 individual sporting federations, the IAAF (International Association of Athletics Federations) now must decide to what degree to apply its own rule, which states shoes "must not be constructed so as to give athletes any unfair assistance or advantage." So as long as the shoes are readily accessible to everyone (and on shelves like the Vaporfly NEXT%), no particular athlete would be given unfair advantage.
On Monday, the IAAF convened its technological committee, which has been studying Nike’s Vaporfly shoes since 2017, involving scientists from the University of Queensland as well as legal experts. The Guardian argues that this committee could be likely to conclude that Nike's new shoes do not provide “motor assistance” to runners. "In other words, if the only power source remains the person running in the shoes, they would be legally compliant," the publication summarizes.
Writing for The New York Times, Amby Burfoot also touched on an important consideration to make when attempting to limit the use of new innovations in sporting events, by saying “With the right material, a thicker sole produces more spring. Without clear restrictions, it is likely only a matter of time before someone comes up with a way to make a shoe with more powerful springs." In short, innovation is inevitable, so we need more specific regulative terms.
It's worth noting an analogous situation involving Speedo, brought to light by Sport Betting Dime. Speedo brought a patented “LZR” full-body swimsuit to the Beijing Olympics in 2008, a swimsuit which increased buoyancy and decreased drag. As a result, 25 world records were set in Beijing, and 24 were set in a LZR suit. Subsequently, full-body suits were eventually banned in competition by FINA (Fédération internationale de natation, the swimming version of the IAAF), but those records still stand today.
Geoffrey Burns, a marathoner and University of Michigan doctoral candidate in biomechanics, expressed one solution by noting that midsole height could be limited across the board. “I don’t want to ban anything,” he said. “We can do most of what needs doing with a simple midsole-height limitation. My fear is, if we don’t do this, in a few years we might end up with footwear that we don’t even recognize as shoes.”
As with the competition that ensued following innovations like Nike Flyknit and adidas Boost, we could be on the verge of another arms race in sneakers.