WHEN THE PUBLIC first noticed Nike's new Alphafly, it didn't look like much: In August 2018 the French Instagram account @RUN'IX posted a photo of Eliud Kipchoge flanked by smiling runners. There, atop the red Kenyan soil, Kipchoge is wearing a nondescript black upper attached to a chunky slab of what looked like the Vaporfly's ZoomX foam. This was the first spark of speculation on how Nike planned to follow up on its world-beating Vaporfly, though Kipchoge had already been testing prototypes since January.
In the two years prior, Nike's new Vaporfly, unique for its thick, bouncy Pebaxbased foam midsole and carbon-fiber plate, had upended the less-is-more maxim governing racing flats by winning-sometimes sweeping-nearly every major marathon it entered. And in the month after those first mysterious photos, Kipchoge, wearing Vaporflys, would claim his first marathon world record in 2:01:39 at the 2018 Berlin Marathon.
More photos of the new prototype, midsole seemingly (bewilderingly) thicker than the Vaporfly's, surfaced every few months until, in October 2019, in Vienna, Kipchoge wore a polished version of the still-unnamed shoe to clock the first sub-two-hour marathon (albeit not an official record) at the Ineos 1:59 Challenge. The following June, the Air Zoom Alphafly NEXT% was released-and, last year, was updated as the Alphafly 2. Meanwhile, Kipchoge has used Alphaflys to lower his official world record to 2:01:09 and claim his second Olympic gold medal in the marathon.
The Alphafly, with its air chambers, is an obvious evolution from the Vaporfly. And it retains the mechanically familiar block of responsive foam stabilized by a heel-to-toe carbon-fiber plate. That's no longer a mystery. But how, exactly, does that system translate physiologically to the fastest marathon ever run? Biomechanists are still figuring that out.
This story is from the Issue 03, 2023 edition of Runner's World US.
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This story is from the Issue 03, 2023 edition of Runner's World US.
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TO RUN 26.2 IS TO FEEL ALIVE
THE SUN IS rising from the east, and the waves of the Pacific crash below to the west.
LEAVE IT UP TO A PIECE OF PAPER TO TEACH YOU TO RUN EASY
BEFORE I FELL for running, I thought the hardest thing about the sport was the fast stuff: the speedwork, the sprints, and the intervals.
WHY-AND HOW-YOU SHOULD RUN DOUBLES
Those are just a few of the titles entered into my training log for the second run of a day.
FIND YOUR RUNNING COMMUNITY, ONLINE OR IN PERSON
I SIGNED UP for my first marathon while sobbing in the back of a rideshare, on my way to the airport to fly to my uncle's funeral.
FUEL WITH WHAT YOU WANT TO EAT
AS AN ULTRARUNNER, I'm all too familiar with the saying that long-distance running is an \"eating contest with a running component.\"
AT THE FERTILITY CLINIC, MY PAST CAUGHT UP WITH ME
I SAT IN the fertility doctor's office white walls, bare wooden desk, opaque window-alone.
THIS IS NOT AN ESCAPE STORY
AT 15, DARLENE STUBBS WALKED AWAY FROM A POLYGAMOUS CULT-THEN DISCOVERED A NEW LIFE AND COMMUNITY THROUGH RUNNING.
RUNNING WITH HANK
How my daughter's rambunctious mutt saved my sanity while she was lost to the darkness.
WHEN I FOUND OUT I HAD MS.I THOUGHT I'D NEVER RUN AGAIN.
I checked the pins on my bib, shimmied my spandex shorts into place, and teed up the stopwatch on my wrist.
A RUNNER'S GUIDE to sleep
Nike rocked the running world in 2018 when it released the Vaporfly 4%, claiming that the shoe could boost a runner's efficiency by that amount.
