Bolt: People will continue to doubt me

Usain Bolt, the world's fastest man, believes it will take time for people to believe that his performances are possible without doping.

The 23-year-old Jamaican, who won three Olympic titles in world record times in Beijing last year, clocked the fastest 100metres ever recorded in Berlin in August, winning the World Championship title in 9.58 seconds - an astonishing 0.11secs faster than his previous world best.

"I'll continue running fast, I am clean without a doubt," said Bolt, who has four of the 10 quickest 100m times in history and five of the top-10 200m times. "As soon as you start running fast there's going to be a problem."

He added: "It's going to take a couple of years for people to start believing that you're actually clean.

"If you continue running fast and doing it clean then over a period of time all the tainting will go away.

"People will continue to say it until that period of time.

"I've been saying this all season. People always say things, the sport has been through a lot, but it's changing, definitely.

"The IAAF is doing a very good job of cleaning up the sport."