Kosgei and Kiplimo take 25 surprise doping tests a year
The two Chicago headliners signed up for roughly four times the testing a normal marathon pool athlete gets, with Nike and their agency paying the bill.
Brigid Kosgei and Jacob Kiplimo have voluntarily entered the Athletics Integrity Unit's enhanced anti-doping program ahead of Sunday's Chicago Marathon, CITIUS MAG reports. Both are already the headline names in the field.
They’ve been testing me three times per week, sometimes two times per week, in Kenya.
For me, I decided on extra tests because I want clean sport and people can trust and know that we are running clean.
The numbers are the story. Each athlete takes at least 25 out-of-competition tests a year, with 100 to 120 analyses run on those samples. Athletes in the standard marathon testing pool average about six out-of-competition tests a year and 12 to 16 analyses. All 25 are unannounced, WADA-compliant and independently administered by the AIU, and beyond that minimum each program is tailored with data and intelligence to deliver what the AIU calls the right test at the right time.
CITIUS MAG says the initiative was athlete-led, and that Nike and their agency Rosa Associati are funding it. It follows the model Sabastian Sawe used before Berlin last year and London this spring. Sawe's 25 tests were crammed into two to three months. For 2026 the AIU recommended spreading the same volume across a full year as a more sustainable approach, and Kosgei and Kiplimo are on that annual version. Both have been in the program since immediately after their spring marathons.
Why they say they did it
Kosgei says the testers have been at her door constantly in Kenya, two or three times a week, and that the point is to show younger Kenyan runners she is clean. Kiplimo says he wanted extra tests so people can trust that he is running clean.
What it actually means
This is not a sanction and it is not a response to any accusation against either runner. It is a voluntary, sponsor-funded program that buys a paper trail, and the context is hard to miss. Kosgei won Chicago in 2019 in 2 hours 14 minutes 4 seconds, a world record that stood until Tigst Assefa ran 2 hours 11 minutes 53 seconds in 2023. Her fellow Kenyan Ruth Chepngetich lowered it again, also in Chicago, in 2024. Chepngetich was later banned after a positive test and is serving a doping ban. That is the shadow over the women's course record, and Kosgei is testing into it.
Kiplimo won Chicago last year in 2 hours 2 minutes 23 seconds and is considered a favorite to repeat on Sunday after running 2 hours 0 minutes 28 seconds for third at the London Marathon in April. Treat the program as what it is, extra evidence voluntarily gathered, not proof of anything on its own.
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