Clement clears a hurdle next to van Zyl during their men's 400 metres hurdles heat at the IAAF World...
Kerron Clement of the U.S. (R) clears a hurdle next to L.J. van Zyl of South Africa during their men's 400 metres hurdles heat at the IAAF World Championships in Daegu August 29, 2011. REUTERS/David Gray (SOUTH KOREA - Tags: SPORT ATHLETICS)