What did Yomif Kejelcha wear for the half marathon world record? A Whoop and an Amazfit
Yomif Kejelcha ran 56:51 for the half marathon at the Media Maratón Ciudad de Buenos Aires on 23 August 2026, taking 29 seconds off Jacob Kiplimo’s 57:20 and becoming the first man under 57 minutes in conditions eligible for a world record. The time is pending ratification by World Athletics.
He ran it with a device on each wrist, which is a lot of hardware for 56 minutes. An Amazfit Cheetah 2 Pro on his left, and a Whoop on his right, both visible in the finish-line photograph below.
The record, and what it beat
Kejelcha first set the half marathon record in Valencia in October 2024 with 57:30. Kiplimo took it to 57:20 in Lisbon in March 2026, and had run 56:42 in Barcelona the year before, a time World Athletics declined to ratify because the course did not meet its rules. Kejelcha’s 56:51 beats the ratified mark by 29 seconds and sits second on the all-time list behind Kiplimo’s unratified Barcelona run.
He already holds the 10 kilometre road world record, and in April he became the second man to run a marathon inside two hours, finishing his debut in 1:59:41 behind Sabastian Sawe in London. The man has no off-season!
One watch to read, one to wear
The two devices do different jobs.
The Amazfit Cheetah 2 Pro is a marathon running watch which he appeared to actually use in the race – World Athletics noted in its race report that he checked his watch as he lifted the pace through the middle of the race. The Whoop MG has no display as it records HR data for looking at recovery afterwards
The device pairing is new for him. At the London Marathon in April he ran a Whoop alongside a Coros Pace 3.
We don’t know if either brand pays him, but it has been confirmed that Coros didn’t earlier in the year.
Amazfit turned Josh Kerr’s mile into a full data release within days so if they were sponsoring him, I’d expect something to be published from them pretty soon!
The pace, in perspective
The average works out at 2:42 per kilometre, or 4:20 per mile, held across 21.0975 kilometres.
- Average pace: 4:20 per mile, 2:42 per kilometre
- Average speed: 22.27 km/h, 13.84 mph
- Each 5km on average: 13:28, a fast parkrun, run four times over plus a further 1.1km
- Average 10km: 26:57
- Average 400m: 64.7 seconds, sustained for the equivalent of nearly 53 laps
Does wearing it make it a good watch?
No. The record establishes nothing about how accurately the Cheetah 2 Pro measures pace or distance, because none of those measurements produced or verified the time. Road course timing did.
What the run does is hand Amazfit an image. A world record photograph with its watch on the wrist is the kind of exposure a brand cannot easily buy, and Zepp Health has spent two years moving the Cheetah line toward serious runners rather than the budget buyers who built the company.
The Whoop on the other wrist is now a common sight among elite athletes who want recovery data without another screen to read.
Quick answers
What watches did Yomif Kejelcha wear for the half marathon world record?
An Amazfit Cheetah 2 Pro on his left wrist and a Whoop on his right, both visible in race photographs from Buenos Aires.
What is the half marathon world record?
56:51, run by Yomif Kejelcha at the Media Maraton Ciudad de Buenos Aires on 23 August 2026. It is pending ratification and beats Jacob Kiplimo’s 57:20 from Lisbon in March 2026.
Why did Kejelcha run with two fitness trackers?
The Amazfit is a running watch with a screen for live pace and distance, which he checked during the race. The Whoop has no display and records physiological data for later review.
What was Kejelcha's average pace for the world record?
2:42 per kilometre, or 4:20 per mile, held across 21.0975 kilometres, an average speed of 22.27 km/h.
Is the 56:51 an official world record?
Not yet. Like all records it is subject to World Athletics ratification. It is the fastest half marathon run in record-eligible conditions.
Source: World Athletics race report.
Last Updated on 24 August 2026 by the5krunner
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tfk is the founder and author of the5krunner, an independent endurance sports technology publication. With 20 years of hands-on testing of GPS watches and wearables, and competing in triathlons at an international age-group level, tfk provides in-depth expert analysis of fitness technology for serious athletes and endurance sport competitors. ID
