Hannah Roberts has won just about everything possible on a freestyle BMX bike except an Olympic title. The 21-year-old American trick artist didn't even need her second run in the finals of the world championships on Monday, posting a score of 91.04 points during her opening run to secure her fourth straight title and fifth overall. Roberts was followed by all five of the riders from emerging powerhouse China, led by silver medalist Sibei Sun and bronze medalist Huimin Zhou.