Matt Shirvington was just a teenager when he burst onto the international athletics circuit.
After setting the Australian 100 metre sprint record at the Commonwealth Games, Matt just missed out on a finals berth at the 2000 Sydney Olympics.
After retiring from the sport, he became a regular on our TV screens.
But now, as a father of three, the track legend is turning his attention to the growing problem of childhood obesity.
Watch the full story below