1994 Comrades Marathon winner Alberto Salazar has been banned from the sport for four years after being found guilty of doping violations.
Salazar runs the Nike Oregon Project and the decision follows a four-year investigation by the US Anti-Doping Agency (USADA) and a two-year court battle behind closed doors.
American Salazar said he was "shocked" by the outcome and would appeal.
"The Oregon Project has never and will never permit doping," the 61-year-old added. "I will appeal and look forward to this unfair and protracted process reaching the conclusion I know to be true."
Dr Jeffrey Brown, a Nike-paid endocrinologist who treated many of Salazar's athletes, has also been banned for four years.
Mo Farah is one of Salazar’s former athletes, but split with the American in 2017, which the BBC can reveal was the same year the coach was first charged by USADA.
The 36-year-old, also a six-time world champion, said: "I'm relieved that USADA has, after four years, completed their investigation into Alberto Salazar. I left the Nike Oregon Project in 2017 but, as I've always said, I have no tolerance for anyone who breaks the rules or crosses a line. I'm glad there has finally been a conclusion."
The Briton has never failed a drugs test and has always strongly denied breaking any rules.
The investigation began after a BBC Panorama programme in 2015.
An independent panel found Salazar and Brown possessed and trafficked a banned performance-enhancing substance and administered or attempted to administer a prohibited method to multiple track and field athletes.
It added that Salazar "tampered and/or attempted to tamper with the doping control process".
The panel also said Salazar and Brown "communicated repeatedly about the athletes of the Nike Oregon Project's (NOP) performance and medical conditions, exchanging information without any apparent formal authorisation by the athletes at the NOP or distinction between Dr Brown's role as an athlete's physician and NOP consultant. Salazar and Brown shared information with the aim of improving the athletes' performance via medical intervention, with a particular interest in increasing testosterone levels."
USADA Chief Executive Travis Tygart praised athletes for having the "courage to speak out and ultimately expose the truth”.
“While acting in connection with the Nike Oregon Project, Mr Salazar and Dr Brown demonstrated that winning was more important than the health and wellbeing of the athletes they were sworn to protect," a statement added.