Bolt vows to turn on the power in London Grand Prix

LONDON: Triple Olympic gold medalist Usain Bolt will use this weekend's London Grand Prix to underline his credentials as the world's best sprinter.

Bolt won gold in the 100m, 200m and 4x100m relay at the Beijing Games last year and holds the 100m world record of 9.69 seconds, but America's Tyson Gay and fellow Jamaican Asafa Powell both believe they can take his crown.

Gay has already recorded the fastest 100m time this year and won gold in the 100m, 200m and 4x100m relay at the World Championships in Osaka two years ago, while Commonwealth 100m champion Powell is unbeaten over the distance at Crystal Palace having run under 10 seconds in his previous three races at the venue.