Athletics has been plagued by blood doping since 1995. Several years ago, some simpletons on this forum were laughting, when I stated that blood doping among Kenyans was rampant. After Kenyan officials implemented a little bit more strict doping controls two years ago, 22 Kenyan dopers have been caught - including Rita Jeptoo, multiple winner of the Boston and Chicago marathons.
During the recent years, many new drugs have been developed and substituted the o'le good classics such as steroids and EPO.
Google: GW 501516, Aicar, SARMs (Ostarine, Andarine), GHRP, GHRH...
It's an utter farce. This is why I don't watch athletics anymore. It has got out of control.