Throughout history, athletes and competitors have always sought a technical advantage that could allow them to train harder and longer, to reach the pinnacle they seek. Along that path, science and engineering has often played a role in finding whatever leg up exists.
But, despite scientific advancements in footwear, racing surfaces and training techniques, one victory still eludes even the most gifted athletes: the sub-two-hour marathon. For decades, it seemed like that dream might never be reached.
Then, Nike unveiled the Zoom Vaporfly 4% Flyknit. The Vaporfly was the culmination of long hours of labor in a lab and looked like it. The sole was oblong and uncentered, its heel peaked with a sharp point. There was a springy carbon fiber plate running through the full length of the midsole.
But, still, there was a method to the madness. Every element of the Vaporfly was designed, from the ground up, to break the two-hour barrier, according to Nike.
Nike named the shoe after the fact that, in order to bring the world record marathon time under two hours, the record-breaking runner would need to be made roughly 4 percent faster than was currently achievable. After months of engineering and testing, the brand believed Vaporfly was ready to break the record. All Nike needed was a runner.
Enter Eliud Kipchoge, the Kenyan long-distance runner who won the Olympic Marathon at the Rio Summer Games in 2016. Kipchoge is arguably the world’s greatest long-distance runner, so the brand naturally enlisted his help.
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Kipchoge’s first attempt was an assisted marathon, with Nike pacemakers in a phalanx ahead of him to decrease wind resistance and keep him steady. It failed.
In 2018, Kipchoge donned a pair of Vaporflys to break the world marathon record in Boston. He ran the 26.2 miles in just 2 hours, 1 minute and 39 seconds, an improvement of 1 minute and 18 seconds over the previous record, the most ever improved by in a single run. His time was close, but still not there.
If one of the best runners in the world was unable to break the record with the Vaporfly, it seemed unlikely anyone could.
However, the Nike engineers who designed the first Vaporfly knew they were not far off from breaking the barrier—and they could prove it. A study conducted by researchers from the University of Colorado’s Locomotion Lab, including a few from Nike’s own Sports Research Lab in Beaverton, Ore., found that—when compared with common marathon shoes from both Nike and Adidas—Nike’s Vaporfly presented a significant advantage.
“Compared with the established racing shoes, the new shoes reduced the energetic cost of running in all 18 subjects tested,” researchers wrote regarding their findings. “Averaged across all three velocities, the energetic cost for running in the Nike prototype shoes was 4.16 and 4.01 percent lower than in the Nike Zoom Streak 6 and Adidas Boost 2 shoes, when shoe mass was matched.”
Scientists found that Nike’s ZoomX foam decreased its weight by so much (the Vaporfly was 51 grams lighter than the Adidas Boost 2 and 4 grams lighter than the Nike Zoom Streak 6) that the inertia of a runner’s leg decreased significantly after each swing. Then, the carbon fiber plate inside helped the runner’s foot act more like a lever, increasing longitudinal stiffness and limiting the ability of the shoe to bend. The Vaporfly was light as a feather but stiff as a board.
But, unfortunately for Kipchoge and Nike, it wasn’t enough. Neither could claim they were the first human and the first brand to break the two-hour marathon.
Kipchoge kept running and Nike kept engineering faster shoes. In the meantime, those who were not so single-minded started to wear the shoes to marathons around the world. In just a few short months, Nike’s Vaporfly became the most popular footwear choice for marathon runners. According to the brand, 46 percent of marathon runners that finished in the top three spots in 2017 wore the Nike Vaporfly 4%.
In 2018, 63.8 percent sported Nike’s marathon shoe, including 58.3 percent of the World Major Marathon winners. The brand had found a way to tap into that market using nothing but solid footwear engineering.
Then, in late April, Nike announced to the world that it had a successor for the Vaporfly, an improvement on its design: the Nike ZoomX Vaporfly NEXT%.
Nike said it compiled what it learned from Kipchoge and other famous runners like Mo Farah and Geoffrey Kirui, and applied that to the previous Vaporfly design. The result is a shoe that features 15 percent more Nike ZoomX foam for improved energy return, while retaining the exact weight of the original. It also incorporates a material technology Nike calls “Vaporweave.” Similar to Flyknit, the new fabrication is lighter, more breathable and less apt to absorb liquid.
Being more weather resistant was a primary goal for Nike’s design team. A common gripe from users of the original was that it tended to retain water in wet conditions, eliminating its proven weight advantage. As a result, the brand also overhauled the new model’s treads to improve its forefoot grip with deeper grooves, assisting with side-to-side movement in adverse conditions.
Nike said its designers looked to sailing for inspiration, hoping to draw from the water-resistant properties of sailcloth.
“This shoe is truly the result of our athletes, sport scientists, engineers and designers closely collaborating throughout the entire process of design, testing and manufacturing,” Brett Holts, Nike’s VP of running footwear said in a statement. “We are all so excited to see the NEXT% continue to push the limits of human performance on marathon courses around the world.”
The new Vaporfly takes its name from the next percentage point to be chipped away from humanity’s athletic limitations. Already, reviews are coming in from the marathoners Nike enlisted to test the new prototype. Japanese long-distance runner, Suguru Osako, praises a design feature promoted by Mo Farah: new off-center shoelaces. Roza Derele, a female runner from Ethiopia, says the added foam in the forefoot gives her an added boost at the end of her stride.
But Nike knows its best review will come from the racetrack. On the day of the Nike ZoomX Vaporfly NEXT%’s release, April 28, Kipchoge won the London Marathon in 2 hours 2 minutes 37 seconds for the second-fastest marathon time ever recorded—but, unfortunately, still below the barrier.