Tyson Gay of us fails dope test

US 100m record holder 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 in Moscow. Gay, the 2007 world champion who had the year’s fastest 100m time of 9.75 seconds, said in telephone conference call he was notified by the US Anti-Doping Agency on Friday that his A sample from an out of competition test on 16  May had returned a positive. ‘I don’t have a sabotage story... I basically put my trust in someone and was let down,’ said Gay, insisting he never knowingly took performance-enhancing drugs.