13-Oct-2024 – Chicago Marathon – 2:09:56 – Nike Air Zoom Alphafly Next% 3
Date of birth: 7-Aug-1994
Nationality: Kenyan
World Record duration: 1 year, 6 months, 16 days (as of 29 April 2026)
The athlete:
When I first publishing my page on the time set by Ruth Chepng’etich at the 2024 Chicago Marathon, I looked closely at the analysis of the performance from sources including Athletics Weekly and the BBC in an attempt to explain the improvement in speed. There were suggestions by some media outlets, most notably LetsRun, that this performance could only have occurred due to some form of impropriety by Chepng’etich. On 17 July 2025 the Athletics Integrity Unit, part of World Athletics, suspended Chepng’etich due to the detection of prohibited substances in the samples she provided as part of standard testing. On 23 October 2025, the Athletics Integrity Unit announced that Chepng’etich was banned for three years after admitting to anti-doping violations.
At the time of writing, the time that Chepng’etich set at the 2024 Chicago Marathon still stands as the Women’s Marathon World Record on the basis that the period in which she was found to have violated anti-doping rules does not extend back to the time of that race. It is important to note however that in its decision the Athletics Integrity Unit found screenshots from Chepng’etich’s phone dating back to 2022 relating to prohibited substances, with the head of the organisation Brett Clothier saying:
“The case regarding the positive test for HCTZ has been resolved, but the AIU will continue to investigate the suspicious material recovered from Chepng’etich’s phone to determine if any other violations have occurred. In the meantime, all Chepng’etich’s achievements and records pre-dating the 14 March 2025 sample stand”.
It is an incredibly sad and dissapointing situation, similar to when Lance Armstrong was found to have conducted long-term and extensive anti-doping violations. In the situation of Armstrong, the damage done to the reputation of cycling is still being felt today. Similar suspicisions are not placed against any distance runner who has performed at the elite level. If the Athletics Integrity Unit were to eventually annul the time set by Chepng’etich at the 2024 Chicago Marathon, this website will be updated accordingly. More information about the investigation that led to Chepng’etich being banned for anti-doping violations can be found in the links below.
The shoes:
Chepng’etich wore the third iteration of the technological powerhouse known as the Nike Air Zoom Alphafly Next%. As written about extensively in my article about Eliud Kipchoge and his demonstration run where he broke the two-hour barrier, the Alphafly combines highly compressive and responsive Pebax foam dubbed ZoomX with Zoom Air pods under the forefoot. Of course, as with all elite marathon running shoes today, the key ingredient is the carbon-fibre plate running through the midsole.
Interestingly, Chepng’etich did not appear to wear the elite version of the Alphafly Next% 3 which tweaks the package to what looks like an even more aggressive plate geometry with yet more foam under the forefoot. Nike has provided this model to many of its elite athletes, World Athletics having approved it for use at the time she ran as the ‘Dev 16E’.
References:
https://www.runnersworld.com/races-places/a41560097/chicago-marathon-2022-results/
https://tonireavis.com/2024/10/13/another-world-record-falls-in-chicago/
https://www.letsrun.com/news/2024/10/ruth-chepgnetich-20957-smashes-world-record-breaks-210-barrier-at-2024-chicago-marathon/
https://www.bbc.com/sport/athletics/articles/c89l29l2dxvo.amp
https://athleticsweekly.com/blog/chepngetichs-20956-world-marathon-record-tests-the-belief-of-fans-1039993637/
https://www.wada-ama.org/en/athletes-support-personnel/anti-doping-process
https://www.chicagomarathon.com/runners/bank-of-america-chicago-marathon-anti-doping-policy/
https://believeintherun.com/shoe-reviews/nike-alphafly-3-first-look/
https://www.runnersworld.com/uk/gear/shoes/a45481094/war-of-the-super-shoes/
https://www.runnersworld.com/uk/gear/shoes/a30777696/nike-alphafly/
https://www.nicekicks.com/how-eliud-kipchoge-and-the-nike-alphafly-made-history/
https://www.believeintherun.com/a-breakdown-of-the-nike-kipchoge-prototype/
https://www.wired.co.uk/article/nike-alphafly-eliud-kipchoge
https://certcheck.worldathletics.org/FullList
https://hypebeast.com/2017/9/nike-zoom-vaporfly-elite-eliud-kipchoge-red
https://techcrunch.com/2018/04/17/nikes-vaporfly-elite-flyprint-leans-hard-into-computational-design/
https://hypebeast.com/2018/4/nike-zoom-vaporfly-elite-flyprint-3d-printed
https://hypebeast.com/2019/2/nike-vaporfly-elite-flyprint-3d-japan-release-info
https://www.athleticsintegrity.org/downloads/pdfs/other/PRESS-RELEASE-AIU-Suspends-World-Record-Holder-Chepngetich.pdf
https://www.athleticsintegrity.org/downloads/pdfs/disciplinary-process/en/AIU-25-059-Ruth-CHEPNGETICH-Decision_FINAL_secured.pdf
https://www.athleticsintegrity.org/downloads/pdfs/other/Press-Release_Howman-Nobody-Above-the-Rules-%E2%80%93-AIU-Bans-Chepngetich-for-3-Years.pdf