Clement of the U.S. and Williams of Britain clear a hurdle in their men's 400 metres hurdles heat during...
Kerron Clement (R) of the U.S. and Rhys Williams of Britain clear a hurdle in their men's 400 metres hurdles heat during the IAAF World Athletics Championships at the Luzhniki Stadium in Moscow August 12, 2013. REUTERS/Phil Noble (RUSSIA - Tags: SPORT ATHLETICS)