Nike launches Alphafly 4 after 33 months: 'biggest leap' in franchise history

"The Alphafly 4 represents the biggest performance leap in the history of the Alphafly franchise — bigger than the jump from 1 to 2, and bigger than the jump from 2 to 3," said Brett Schoolmeester, Nike's senior vice president of running footwear.

Nike announced Thursday that it will release the Alphafly 4, the latest model in its top-tier running shoe franchise, at the end of next month — 2 years and 9 months after the Alphafly 3. The new shoe was developed to deliver peak performance, cutting weight by 5 percent and boosting propulsion by 10 percent compared with its predecessor.

The Alphafly line features a carbon plate embedded in the midsole to enhance energy return and propulsion. The shoe gained widespread attention — and helped spark the carbon-plate running shoe craze — when marathon great Eliud Kipchoge wore it during the 2019 INEOS 1:59 Challenge, in which he became the first person in history to run a marathon in under two hours.

Nike has typically released a new Alphafly model roughly every two years: the Alphafly 1 in June 2020, the Alphafly 2 in November 2022, and the Alphafly 3 in January 2024. The 2-year-9-month gap before the Alphafly 4 is the longest in the franchise's history, reflecting the extensive development work Nike put into the new model, the company said.

The Alphafly 4 retains the same core architecture — Air Zoom units, a carbon fiber Flyplate and ZoomX foam — while refining each component. Nike incorporated feedback from elite athletes and everyday runners, as well as findings from its Nike Sport Research Lab (NSRL).

The Air Zoom units are now welded at the seams using radio-frequency vibration, making them 30 percent lighter and softer than the previous generation while also reducing landing noise. The carbon Flyplate features a wider base for improved stability. The upper midsole uses the new ZoomX LT foam, which is 17 percent lighter and delivers 8 percent greater energy return than before. The upper is constructed with Atomknit 2.0, a lightweight, breathable material that provides a secure fit.

Emily Farina, a senior biomechanics researcher at the NSRL, said at a Zoom press briefing on Tuesday that the Alphafly 4 delivers 10 percent greater energy return than the Alphafly 3 while weighing 10 grams — or 5 percent — less. Biomechanical testing confirmed improvements in both traction and stability, she said.

Schoolmeester said the new shoe was particularly exciting because it achieved the largest performance gain since the Alphafly line was first introduced. "It would be easy to assume that with each successive generation, the rate of improvement slows and it becomes harder to find additional gains — but this time, the performance improvement was actually larger, and the pace of development was faster," he said.