Doping means athletes taking illegal substances to improve their performances. There are five classes of banned drugs, the most common of which are stimulants and hormones. There are health risks involved in taking them and they are banned by sports' governing bodies.
According to the UK Anti-Doping Agency, substances and methods are banned when they meet at least two of the three following criteria: they enhance performance, pose a threat to athlete health, or violate the spirit of sport.
