When swimmer Mack Horton refused to share a podium with Sun Yang, accusing him of being a drug cheat, what he didn’t know is that one of his own teammates had tested positive for a banned substance. On Friday Shayna Jack will attempt to clear her name as she faces a four year ban. The consequences for athletes are serious– stripped of medals, barred from competition and a reputation in tatters, it hardly seems worth the risk. Time and time again athletes get caught, but is the testing regime keeping up?