Tyson Gay tests positive for banned substance

United States 100 metres record holder and 2007 triple world championship gold medallist Tyson Gay said on Sunday he had tested positive for a substance he could not identify and was pulling out of next month's world championships, according to Reuters.

Gay, the joint second fastest man over 100 metres with 9.69 seconds,  said in telephone conference call he was notified by the U.S. Anti-Doping Agency (USADA) on Friday that his A sample from an out of competition test in May had returned a positive.

The B sample is yet to be tested, said a tearful Gay.