The distance covered by Kiptum in the World Record race may be short of full marathon distance

When Kelvin Kiptum ran his 2:00:35 world record at the Bank of America Chicago Marathon on October 8, he did so by running his second half in 59:47 — a split that, until recently, would have been unfathomable for a marathoner. But considering Kiptum closed his win at the London Marathon six months earlier in 59:45, his second-half split in Chicago seemed realistic.

But what about some of the individual mile splits in the second half? Did Kiptum really run a 4:21 19th mile and a 4:18 22nd mile? Those are the two fastest mile splits ever recorded in a major marathon (with the 4:21 being tied with Amos Kipruto‘s 25th mile at 2022 London), much faster than the 4:33.6 pace Kiptum averaged in the second half. It seemed unrealistic, particularly since Kiptum’s last remaining rival, Daniel Mateiko, stayed with him for mile 19.

So LetsRun.com, acting on a tip, did a little investigation (full details below) and quickly concluded that something was amiss. Either that, or Kiptum somehow managed sub-4 mile pace between 30k and 19 miles (30.5775k) and between 35k and 22 miles (35.4056k). We shared our findings with Chicago organizers, who confirmed that the mile markers were misplaced and/or splits were taken incorrectly.

“The mile and kilometer split times available to members of the media…are manual split times entered by spotters on lead vehicles,” wrote Chicago Marathon senior director of communications Alex Sawyer. “The splits are provided to give media a better understanding of the lead group’s pace during the event, with timing mats at every 5K providing the most accurate reading.

“Your note was shared with our operations team who confirmed discrepancies at Mile 19, Mile 22, 37K and Mile 23. The discrepancies were attributed to the misplacement of on-course signage and/or error when inputting times into the system.”

Chicago still has no doubts that Kiptum ran the full marathon distance in his world record.

“As a World Athletics Platinum Label event we work with two independent World Athletics A certified course measurers to conduct an official course measurement,” Sawyer wrote. “The 2023 Bank of America Chicago Marathon course was measured and certified this year.”