Olympic cycling champion Tyler Hamilton of the United States has asked the Court of Arbitration for Sport in Lausanne, Switzerland, to overturn his two-year ban for blood doping.
Hamilton was banned April 18th by the American Arbitration Association after tests revealed he had someone else's blood cells in his body. A blood transfusion can increase an athlete's endurance by providing extra oxygen-carrying red blood cells.
Hamilton tested positive September 11th during the Tour of Spain, one month after he won the individual time trial gold medal at the Athens Olympics. He had a similar test result in Athens, but it was ruled inconclusive after his second sample was mishandled.
Hamilton has denied any doping violations and has criticized the International Cycling Union for its testing procedures. The Swiss sports court usually issues its decisions within four months of an appeal.
Some information for this report provided by AP.