Since the mid-1960s, sports authorities with the support of other Government agencies have attempted to prevent high-level competitive athletes from enhancing their performance with stimulants or enhancing their training with steroids, growth hormones, blood boosters and other related practices known as 'doping'. This attempted control has been based on establishing a list of banned substances, testing athletes for these and subsequently punishing those found guilty. A number of critics have argued that 'anti-doping' policy and testing has consistently failed to stop this form of cheating.