Eliud Kipchoge’s first, and likely last, New York City Marathon didn’t end with a victory, but it did end with a story. The 41-year-old Kenyan finished 17th in 2:14:36, completing his run of all World Marathon Majors.
More surprising than the result, though, was what he wore while doing it.
Kipchoge’s white long-sleeve top, with its unusual mesh pattern and visible vents, wasn’t something you could buy in any store. It was a one-off Nike prototype made from a new material called Radical AirFlow, a fabric originally designed for ultra-trail runners competing in the heat of races like Western States and UTMB.
The idea behind Radical AirFlow is simple enough: help the body cool itself more efficiently. Nike’s engineers built tiny, funnel-shaped air channels into the knit fabric to direct air toward the skin as a runner moves, speeding up the evaporation of sweat.
It’s essentially a wearable ventilation system, inspired by the Venturi effect from fluid dynamics, the principle that air speeds up as it passes through narrow openings.
According to Nike’s apparel innovation director Jahan Behbahany, the goal was to “accelerate the velocity of airflow to the skin and help speed up that evaporative cooling process.”
Kipchoge received early samples last summer at his training camp in Kaptagat, Kenya.
As usual, he ran in them, took notes, and sent pages of feedback to Nike’s design team. His biggest suggestion was to add extra side vents to increase airflow and adjust the fit so the top didn’t swing while running. Designers made the changes using his digitized body scans to fine-tune the sizing.
“Every alteration we made for Eliud was based on his feedback,” said Nike product manager Emily DeLess.
When he finally tried the updated version, Kipchoge’s response was simple: “The material is wonderful, friendly to the skin, and absorbs moisture very fast. The magic of this top is how it evaporates the sweat.”
On race day, he paired the long sleeve with a prototype pair of Nike Alphafly racing shoes and a development version of the Coros Pace 4 watch.
Even though his time wasn’t headline-grabbing, the moment carried weight. He became a seven-star finisher, closing the book on his competitive marathon career and hinting at a new goal, to run marathons on all seven continents as a way to inspire others and raise money for charity.
The Radical AirFlow top isn’t available yet, with Nike saying it’ll launch in spring 2026, but its presence on Kipchoge signals where performance gear is headed next. After years of focus on foams, plates, and shoes, apparel is becoming part of the performance equation.
And if history is any guide, whatever Eliud Kipchoge chooses to wear now, the rest of us will probably be wearing soon enough.
