Norfolk's Chrissie Wellington has described the Herculean effort needed to land her fourth world ironman triathlon title in five years as 'the race of my life.'

The 34-year-old, who won a hat-trick of world ironman titles from 2007 to 2009, was pushed all the way by Australian champion Mirinda Carfrae, finishing just three minutes ahead in a new course record time of eight hours 18 minutes and 13 seconds.

Incredibly, the former Downham Market schoolgirl, whose family live in Feltwell, clawed back a 22-minute deficit at the start of the final transition of a race which involves a 2.4 mile swim, 112-miles bike ride and 26.2 mile run.

But most remarkable of all is that, having approached the trip to Hawaii feeling she was in the form of her life, she went into the race on the back of a series of injuries, the worst of which came in a bike crash on the Tuesday before, when she bruised her hip and elbow and tore a pectoral muscle. It left her in such pain as she tried to swim on Tuesday that she had to go to hospital.

'I appreciated that the crash had hampered my preparation mentally and physically,' said Wellington, who missed last year's race through illness. 'My confidence coming in always had an asterisk. There were times that my body was going to give up on me. But I had faith in my body and mind to push through it. This race means more to me than anything. It's the sweetest victory. I just proved that anything is possible.'

Hampered during the swim by her torn muscle, Wellington admitted she was a little worried when placed sixth after the bike ride but pushed hard in the marathon, finishing in 2hrs 52 minutes.

'I had confidence in my run but there was always that question mark of the impact of the accident. I had to dig to the deepest depths I have ever known,' added Wellington, who knocked a minute off her own world record in Germany two months ago.

The men's race was won, for the third time, by Australia's Craig Alexander, also in a course record time.