London 2012: Tyson Gay on how he can beat his Jamaican rivals

American sprinter Tyson Gay admits it will be "very difficult" to beat the Jamaicans for the 100m Olympic title at the London Games, and believes he will have to race at least 9.70 seconds to win a medal.

Gay promises to be on his "A game" when he faces Jamaican trio Yohan Blake, Asafa Powell and Olympic champion Usain Bolt.

The American, who will compete at this Friday's Diamond League meeting in London, also discusses recovering from injury and his excitement at competing at the Olympics in two weeks' time.