Dayron Robles of Cuba (C) clears the last hurdle next to Liu Xiang of China (L) and Jason Richardson of the US (R) as he sprints to victory in the men's 110 metres hurdles final at the IAAF 2011 World Championship in Daegu August 29, 2011. [Photo/Agencies]

Dayron Robles of Cuba (2nd R) clears a hurdle as Liu Xiang of China (2nd L) knocks his over on Robles' way to winning the men's 110 metres hurdles final at the IAAF World Athletics Championships in Daegu August 29, 2011.[Photo/Agencies]