The expulsion of an American judo player from the London 2012 Olympic Games on Monday after he tested positive for marijuana prompted scientists to question the sense behind the drug's inclusion on the World Anti Doping Agency's (WADA) banned list…"It's hard to imagine how smoking a joint or eating marijuana brownies is going to help somebody in judo," said Michael Joyner, a member of the Physiological Society and a researcher at the Mayo Clinic in Minnesota in the United States. "My advice to WADA is that they should focus on drugs that are clearly performance enhancing in the sports where they are clearly performance enhancing."

Additional coverage: Yahoo! Canada

Reuters by Kate Kelland

Tags: Dr. Michael Joyner, London Olympics, marijuana, Mayo Clinic Rochester, performance enhancing drugs, Reuters, Sports Medicine, World Anti Doping Agency