Injuries ransack worlds

Injuries to several top athletes will rob this month's World Athletics Championships of many mouth-watering duels at the sport's showcase event.

Jamaican sprint star Usain Bolt will be starved of a run-off against American arch-rival Tyson Gay and compatriot Asafa Powell, the fastest man over 100m this year.

Both Gay and Powell have been ruled out due to injuries, clearing the path for Bolt in his quest to defend his world sprint double.