Bershawn Jackson of the U.S. clears a hurdle during his men's 400 metres hurdles semi-final heat at the...
Bershawn Jackson of the U.S. clears a hurdle during his men's 400 metres hurdles semi-final heat at the IAAF 2011 World Championships in Daegu, August 30, 2011. REUTERS/Mark Blinch (SOUTH KOREA - Tags: SPORT ATHLETICS)