Published

The American's Vuelta victory might be one of the greatest performances in the history of the sport—if only it hadn't taken place under a cloud of doping suspicion. Horner maintains he's clean, and released six years worth of blood data to prove it. But his troubles just won't go away.

In the wake of Chris Froome's brilliant stage victory, we turn to one of the foremost doping experts to see what his performance signals in the peloton.