US anti-doping chief sceptical of investigation into Chinese swimmers
Swimmers were cleared of doping after positive testsWada has received criticism for handling of caseTravis Tygart, the head of the United States Anti-Doping Agency (Usada), said on Monday he has doubts about the effectiveness of an investigation into positive drug tests by 23 Chinese swimmers.The World Anti-Doping Agency (Wada) has faced mounting pressure to …