Ugandan distance-running sensation Jacob Kiplimo has strengthened his commitment to clean sport by voluntarily enrolling in an enhanced anti-doping programme ahead of his return to the streets of Chicago, where he will seek to defend his marathon crown on Sunday, October 11, 2026.
The reigning Bank of America Chicago Marathon champion has joined former marathon world-record holder Brigid Kosgei of Kenya in the athlete-led initiative administered by the Athletics Integrity Unit (AIU). The programme, funded by Nike and the athletes’ agency Rosa Associati, is designed to reinforce confidence in the integrity of elite marathon running through more frequent and comprehensive drug testing.
Kiplimo’s decision comes at a pivotal moment in his marathon career, with the Ugandan arriving in Chicago among the leading contenders following an impressive performance at the London Marathon in April, where he clocked 2:00:28 to finish third and become the third-fastest marathoner in history.
The enhanced programme goes beyond the standard testing requirements for athletes in the marathon testing pool. Participants must undergo at least 25 unannounced out-of-competition tests annually, generating between 100 and 120 analyses. By comparison, athletes in the regular testing pool average approximately six out-of-competition tests and 12–16 analyses per year.
All the required tests are conducted independently by the AIU in accordance with World Anti-Doping Agency (WADA) standards. Additional testing is tailored to individual athletes using intelligence and data to determine the most appropriate testing methods and timing.
Kiplimo and Kosgei entered the programme immediately after their respective spring marathons, adopting an annual testing schedule that the AIU considers more sustainable than the compressed approach previously used by Kenyan marathon star Sabastian Sawe ahead of his Berlin Marathon campaign.
Sawe underwent his 25 required tests over a period of two to three months. For the 2026 programme, the AIU recommended spreading the same testing volume across an entire year, a model now being followed by Kiplimo and Kosgei.
For Kiplimo, the decision is rooted in a desire to protect the credibility of the sport and assure fans that performances on the road are achieved fairly. “For me, I decided on extra tests because I want clean sport and people can trust and know that we are running clean,” Kiplimo said.
Kosgei has similarly embraced the initiative, explaining that the frequent testing she has experienced in Kenya is intended to set an example for younger athletes.
“They’ve been testing me three times per week, sometimes two times per week, in Kenya. It’s to prove to the juniors and young generation that I am clean,” she said.
Their participation comes against a backdrop of heightened scrutiny in marathon running. Kosgei set a women’s world record of 2:14:04 when she won the Chicago Marathon in 2019, a mark that stood until Tigst Assefa improved it in 2023. Ruth Chepngetich subsequently lowered the record in Chicago in 2024 before later receiving a doping ban following a positive test.
By voluntarily submitting to more rigorous testing, Kiplimo and Kosgei are seeking to demonstrate their commitment to transparency and strengthen public confidence in elite distance running.
Beyond his commitment to clean sport, Kiplimo faces an important competitive challenge as he prepares to defend the title he claimed in 2025.
The Ugandan won last year’s Chicago Marathon in 2:02:23, an exceptional performance achieved during only his second career appearance over the marathon distance. His subsequent run at the London Marathon in April, where he registered a personal best of 2:00:28, further underlined his ability to compete among the very best marathon runners in the world.
Kiplimo’s credentials extend well beyond the marathon. He is a former half-marathon world-record holder, having established a ratified mark of 57:20 at the Lisbon Half Marathon in 2026. He also boasts an outstanding cross-country and track record, including senior World Cross Country titles in 2023, 2024 and 2026, alongside Olympic and World Athletics Championships medals.
His return to Chicago, therefore, presents an opportunity not only to retain his title but also to build on the momentum generated by his historic performance in London.
Kiplimo’s preparation for the title defence has reportedly involved substantial training volumes, reflecting the demands of competing at the highest level of marathon running.
The Ugandan has been covering approximately 220 kilometres (137 miles) per week, doubling on most days except during long-run sessions. His longest run has reached 40 kilometres, almost the full marathon distance.
The Chicago Marathon’s flat and fast route winds through 29 neighbourhoods in the American city, starting and finishing in Grant Park. The 48th edition is expected to attract approximately 55,000 runners and 1.7 million spectators, making it one of the major fixtures on the international road-running calendar.
Kiplimo will face a competitive field that includes Kenya’s Amos Kipruto, who finished second in Chicago in 2025 and third in 2024, with a personal best of 2:01:39. Ethiopia’s Milkesa Mengesha, the 2025 Shanghai Marathon champion, will also make his Chicago debut, while American Clayton Young arrives seeking strong home-country performances after competing at the Paris 2024 Olympics.
With the men’s course record standing at 2:00:35, set by Kelvin Kiptum in 2023, the race also offers the possibility of a historic time if conditions and competition align.
For Kiplimo, the immediate target is clear: successfully defend his Chicago Marathon title and become the first man to achieve that feat since the late Sammy Wanjiru won consecutive editions in 2009 and 2010.