The track coach Alberto Salazar was accused by a former assistant and a former runner who trained under him of breaking doping rules, according to a report by ProPublica and the BBC.
Steve Magness, a former assistant at Salazar’s Nike Oregon Project, said he had seen a document that said the Olympic silver medalist Galen Rupp was on testosterone medication. Rupp denied the claim.
In the report, Salazar said he had “strictly followed” doping rules. He did not respond to several phone and email requests for comment.
Salazar, a three-time New York City Marathon winner, is the country’s pre-eminent track coach, and he leads a team that includes not only Rupp but also the Olympic gold medalist Mo Farah of Britain and the American teenage sensation Mary Cain.