The Kenyan marathoner faces a ban from competition and elimination of her recent results.
Doping and extortion scandal could have widespread implications for the Russian athletics federation.
Rita Jeptoo's agent speaks on his athlete's failed drug test and discusses the depth of Kenya's doping problem.
The Kenyan was tested in late September before defending her Chicago Marathon title.
Do you know what's really in your sports nutrition supplements?
The 8-time U.S. road champion says he is retiring from the sport.
The training partners of runners on performance-enhancing drugs probably also benefit.
The 37-year-old tested positive for a banned substance last year at a race in Mexico.
The long-term metabolites method can detect steroids that were taken more than six months prior.