The International Olympic Committee, like most sporting associations, bans the use of performance enhancing drugs. The World Anti-Doping Agency says the drugs pose health risks to athletes and jeopardize the integrity of athletic competition. Still, allegations and revelations of doping among the world's best athletes persist, and the issue of doping could cast a shadow over the the upcoming Olympics in Beijing. Anti-doping officials say the rash of bad publicity is also a sign of progress. VOA's Brian Padden has the story, with additional reporting by Peter Heinlein in Addis Ababa, Kurt Achin in Seoul, and Mandy Clark in London. (Part 2 of 5)

Ethiopian distance runner and two-time Olympic gold medal winner Haile Gebrselassie says training at 3,000 meters above sea level gives him a natural advantage in competition. He also says using performance-enhancing drugs is cheating.

"It is always what I said. I can cheat you," he said. "I can cheat 1,000 of them. But how can I cheat myself?"

Yet some athletes have been cheating for years, using banned substances like steroids to get that winning edge.

Three-time Olympic gold medalist Marion Jones cries as she addresses the media during a news conference outside the federal courthouse in White Plains, New York, 05 Oct 2007

Last year, U.S. Olympic track star Marion Jones admitted she had lied to investigators about using performance enhancing drugs. 

"As everyone can imagine, I'm very disappointed today," she said. She was stripped of her five Olympic medals from the 2000 Sydney games and sentenced to six months in jail.

While the negative publicity involving doping and top athletes can taint the Olympics, it also sends a message that the use of performance-enhancing drugs will not be tolerated.

"Every athlete out there, I truly believe, knows that it's wrong to cheat," says Travis Tygart, the head of the U.S. Anti Doping Agency.

The agency is supposed to insure a drug free playing field. It conducts 8,000 random tests a year on U.S. Olympics athletes to detect banned drugs like steroids that can build muscle but also lead to kidney disease and cancer. It provides guidance on which drugs are prohibited. And it punishes athletes who break the rules.

"In a typical steroid case, it is a two year suspension, disqualification of results for a first offense," said Tygart. "It can be up to life for a second offense."

Most countries now have programs to police and support Olympic athletes. South Korea's Olympic program encourages athletes to consult medical staff before taking medications, even herbal supplements.

South Korean judoka Jang Sung-ho raises his arms on the winners' podium of the men's under 100kg in the Asian Games at the Qatar Sports Club in Doha, 02 Dec 2006

Jang Sung-ho was the judo silver medal winner in the Athens Olympics. He says stories of past athletes losing their medals for inadvertently using banned substances have made today's Olympians cautious.
 
"A runner broke rules once by taking cold medicine got from pharmacy long time ago," he said. "Afterwards, all athletes always get medicines from pharmacies in the training center."

While increased education and enforcement have made cheating more difficult, it is still possible. Peter Sonksen, a professor of endocrinology at St. Thomas' Hospital in London, has advised the International Olympic Committee on doping. He says new drugs like human growth hormone are hard to detect. He says reliable tests have to be developed to keep sports free of drugs.

"I think the answer is a continuous battle against the cheats," said Sonksen. "It has been for twenty years. It will be for forever I think."

Anti-doping officials say most athletes welcome increased testing as a way to ensure the integrity of the Olympic games.