A cloud was cast over the great tradition of Kenyan distance running Friday when Rita Jeptoo, winner of the Boston and Chicago marathons the past two years, tested positive for a banned substance, international officials said.
Jeptoo, 33, who has won Boston three times and Chicago twice, is by far the most prominent Kenyan runner to have failed a doping test. She had a positive test on an A sample for an unnamed banned substance, according to the World Marathon Majors, which represents the world’s six most prominent marathons. But under antidoping rules, a second sample of the same test must come back positive for her to be found guilty of a doping violation by the International Association of Athletics Federations, track and field’s international governing body.
Jeptoo is the second high-profile female marathon runner to be entangled in a doping scandal this year. In April, Liliya Shobukhova of Russia, who has the second-fastest women’s marathon time, received a two-year ban after abnormalities were found in her biological markers that are used to detect evidence of doping.
Along with neighboring Ethiopia, Kenya has developed the world’s richest tradition in distance running. In recent years, though, the sport has grown more complicated there, characterized by wondrous achievement and undermined by evidence of doping as money and interest have bloomed and technology has grown more sophisticated.
In September, Dennis Kimetto of Kenya ran 2 hours 2 minutes 57 seconds at the Berlin Marathon, making him the first person to run 26.2 miles faster than 2:03 and shattering the world record by 26 seconds. His victory spurred further debate about when a sub-two-hour marathon might be run.
But then an antidoping task force last month criticized Kenya’s track and field federation for what it said were lax efforts to catch athletes using banned substances.
More than 30 athletes have tested positive for banned substances in recent years, a report by the task force said. Pharmacies, clinics and athletes’ representatives have assisted in the procurement of prohibited drugs, it said. The blood-boosting drug EPO, which enhances oxygen-carrying capacity, was one substance mentioned in the report.
Officials with the World Anti-Doping Agency, who expressed frustration with efforts in Kenya, recently met with Kenyan officials about the country’s efforts to combat the use of prohibited substances.
On Sunday, after the New York City Marathon, Jeptoo was to receive a check for $500,000 for winning the World Marathon Majors, a prize for the top male and female runners for performances at races in Tokyo, Boston, London, Berlin, Chicago and New York in a two-year cycle. That was postponed.
“The stakes are so high,” said George Hirsch, chairman of the board of New York Road Runners, which organizes the city’s marathon, speaking in general about the temptation to use banned substances in a country such as Kenya. “It’s far more money than almost anybody in that country could earn in a lifetime.”
Any formal sanctions against Jeptoo would be levied by the I.A.A.F., which has not yet announced a doping violation or any potential ban.
The World Marathon Majors has joined the I.A.A.F. in helping to provide more out-of-competition testing, considered the only reliable way to catch those using banned substances. Nick Bitel, general counsel of the marathon group, said Friday, “Cheats need to understand that they are not welcome in our sport and that they will be caught.”
Although Jeptoo was not competing in Sunday’s race, the news of her positive test was a distraction for the final major marathon of the year. Many elite runners heard about Jeptoo’s positive doping test on their way to, or at, a scheduled news conference Friday morning.
Instead of talking about his attempt to become the first man to win three New York City Marathons in a row since Alberto Salazar in 1982, Geoffrey Mutai, another Kenyan standout, was confronted with questions about how often he had been drug-tested and whether he thought he was running on a level playing field.
For years, it has been said that many Kenyan distance runners refuse to take even an aspirin for a headache. And some international experts cautioned against painting all Kenyans with a brush of skepticism.
“I don’t know that you can extrapolate or make any general findings or conclusions until we know the circumstances,” Bitel said.
Yet the number of positive tests in Kenya has risen sharply in recent years, which could reflect increased testing as much as growing drug use.
Jeptoo is the third runner to test positive among one of Kenya’s most successful training groups, which has Federico Rosa as its manager and Claudio Beradelli as its coach. Rosa and Beradelli, who are from Italy, denied any involvement in doping.
The Rosa group, founded by Federico Rosa’s father, Gabriele, a highly respected marathon coach, has produced such top stars as Paul Tergat, a former world-record holder in the marathon, and Sammy Wanjiru, the 2008 Olympic champion.
But the training group — and by extension, Kenyan distance running — has come under increased examination. Mathew Kisorio, a former member of the group, received a two-year ban in 2012 and later told the German television network ARD that doping was not rare in Kenya.
“I went with it because everyone told me I wasn’t the only one — and none of the others got caught for doping,” he said. “I know that a lot of medical substances are used, which are injected straight to the blood for the body to have more oxygen. And when you run, you run so smooth. You have more stamina.”
Jemima Sumgong, another Rosa group runner, also received a two-year ban after a failed doping test in 2012, but it was later reversed. Sumgong, who is scheduled to compete in Sunday’s marathon, declined to comment on Jeptoo’s case but said that in general, when it came to the use of performance-enhancing drugs, “we athletes, we are not happy about it.”
Rosa said Friday that he had been cooperating with the I.A.A.F. in investigating the rising number of positive doping tests in Kenya.
“It’s surprising on one side, not surprising on the other because of a lot of problems in Kenya about this,” Rosa said of Jeptoo.
Rosa said “there’s a fear” doping was becoming commonplace in Kenya, adding, “For sure, we will go legally after the people that put Rita in this situation, and probably also Rita if we found out she is cooperating with them.”