Usain Bolt's main 100m rival Andre De Grasse out of world championships

• Canadian is out for the season after suffering a hamstring injury• 'Injuries are a part of the sport ... I'll be back stronger and faster than ever' Andre De Grasse, the Canadian widely considered to be Usain Bolt's biggest rival for 100m gold at the World Athletics Championships in London, has been forced to pull out of the event after tearing a hamstring. Related: Usain Bolt: Lose? I can't believe you're asking me. We won't have that problem Related: Usain Bolt warns fellow athletes: sto...