Asafa Powell (L) and Tyson Gay in Brussels, 2009

Asafa Powell (L) and Tyson Gay in Brussels, 2009

*Former double world sprint champion Tyson Gay and former world 100 meters record holder Asafa Powell delivered further blows to their troubled sport after testing positive for banned substances.

Gay, on Sunday, pulled out of next month’s Moscow world championships after testing positive in an out-of-competition test. Tyson has run the fastest three 100 meters of the year and his clash with Jamaica’s Olympic 100 and 200 champion Usain Bolt would have been the highlight of the championships.

Instead he has withdrawn from Friday’s Diamond League meeting in Monaco and the world championships on the worst day of a bad week for the central sport of the Olympic Games.

Gay, 30, told two reporters in a telephone conference call that he had been notified by the U.S. Anti-Doping Agency (USADA) on Friday that his A sample from an out-of-competition test on May 16 had returned a positive.

“I don’t have a sabotage story. I don’t have lies…I basically put my trust in someone and I was let down,” said Gay, who added he had never knowingly taken a performance-enhancing drug.

Gay, the 2007 world 100 and 200 champion, said he could not reveal the substance or how the positive occurred.

Also on Sunday, Powell and Olympic 4×100 meters relay silver medalist Sherone Simpson said they had both tested positive for the stimulant oxilophrine at last month’s Jamaican championships.

Oxilophrine has similar properties to ephedrine, although it has a different chemical structure, and both are on the World Anti-Doping Agency banned list.

Powell, 30, who has been in good form recently said he had not willfully taken supplements or substances that broke any rules. “I am not now, nor have I ever been, a cheat,” he said in a statement.

Simpson, 28, who finished equal second in the 100 meters at the 2008 Beijing Games and won a gold medal in the 2004 Athens 4×100 meters relay, also denied knowingly taking a banned substance.

“This is a very difficult time for me,” she said in a statement. “As an athlete, I know I am responsible for whatever that goes into my body. I would not intentionally take an illegal substance of any form into my system.”

Earlier sources close to Jamaican athletics said five athletes, including two Olympic medalists, had tested positive for banned performance-enhancing drugs at the championships.

The managers for Bolt and world 100 meters champion Yohan Blake said their athletes were not involved. Blake did not compete at the championships because of injury while Bolt won the 100 meters.