While Liu was once the unquestioned favorite, the loss of his world record, a sore hamstring and lackluster season have raised doubts.

• 刘翔曾经是无可争议的热门夺金人选，但近来世界纪录被打破，肌腱伤痛，以及近来成绩欠佳等等引起了人们的疑虑。