By Gina Kolata

c.2008 New York Times News Service

Just one failed drug test has been announced at the Beijing Olympics, for a female Spanish cyclist who tested positive before the games began.

But Jamaican sprinters say they are being subjected to an unusual number of drug tests and that each time they are tested, the procedure can disrupt their training.

Asafa Powell, the world-record holder in the 100 meters until his countryman Usain Bolt broke it in May, has been tested at least once a week since the track season started in May, said Paul Doyle, his agent.

Bolt has been tested three or four times in the past 12 days, according to a member of his camp who asked not to be identified because he was not authorized by the team manager to speak publicly.

The 100 meter heats begin Friday.

Sandrine Tonge, a spokeswoman for the International Olympic Committee, said the group will conduct 4,500 drug tests on Olympic athletes from the opening of the games until the close. She said the committee does not disclose how often it tests individual athletes. “We reserve the right to test athletes whenever necessary,” Tonge said.

A test can take an hour or more, disrupting an athlete’s day. It involves taking a urine sample and a blood sample, and athletes sometimes find themselves having to drink fluids and wait until they are able to urinate for the testers.

The testers do not take enough blood to affect an athlete’s performance, said Dr. Neils Secher, an exercise researcher at the University of Copenhagen. A drug test requires 5 milliliters of blood, Secher said. But, he explained, “you would have to take several hundred milliliters of blood to have an effect.”

Doyle, though, says he wishes the issue had not come up, adding that he was reluctant to answer any questions about the frequency with which Powell was tested.

“To be honest, we are trying not to have drugs be the topic of the Olympics,” he said.