Usain Bolt is considering a future career in football or long jump, but on the eve of his first tour of Australia, defending his Olympic titles is his priority, writes Daniel Lane.

He's acknowledged as the fastest man in history but Jamaica's Usain Bolt doesn't want to be described as a ''legend'' until he defends his Olympic 100 and 200 metres titles in London in 2012.

Bolt, who set the world record when he ran the 100m in 9.58 seconds last year, agreed the clock confirmed he was great, but added he needed to win in London to justify the legendary tag people had bestowed upon him.

''People compare [players from different eras] about who was the best cricketer but I'm the fastest man in the world, you can't debate that - this is true,'' Bolt told The Sun-Herald from his home in Jamaica.