The scientist in charge of the anti-doping laboratory for next year's Olympics in London says it will be more difficult for athletes to cheat through blood doping.
Professor David Cowan has spoken about a new test for blood doping, a technique in which athletes transfuse their own blood to improve performance.
Several Olympic competitors have been accused of blood doping, but scientists have so far failed to come up with an effective test to prove it.
Professor Cowan told the BBC that might be about to change in time for London 2012.
