Paula Radcliffe has gone from wanting to punch the walls to bursting into tears during one of the toughest years of her career.

Radcliffe will run her first marathon for 12 months on Sunday, when she takes to the line in New York as defending champion.

But the past year has been littered by injury setbacks. The most serious was a fractured toe, which forced her out of the London Marathon in April, while a hamstring complaint cost her the chance of going for gold at August's World Championships in Berlin.

The 35-year-old had been on the verge of returning to action at the World Half Marathon Championships in Birmingham earlier this month but a bout of tonsillitis scuppered that opportunity.

"It's been one of the toughest years I've had - particularly as I've done all the work for the races and not been able to compete," said Radcliffe. "And I've probably been a total nightmare to live with. I've been flitting between wanting to punch a hole in the wall to wanting to start crying.

"But Isla [Radcliffe's daughter] has been great at giving me perspective. I might be wallowing and she'll just turn round and want to sing 'The Wheels On The Bus', which snaps you out of it pretty quickly."

Despite a dire year since winning her third New York Marathon title last November, the marathon world record holder is still the favourite for victory across the Atlantic at the weekend.

Radcliffe is confident she has the bettering of the field. "I won't be giving my time a lot of thought," she said. "My single goal is to go win the race and I feel in the shape to do it.

"New York's always been a positive race for me. I just can't wait. The hunger is really there for Sunday."

Arguably the biggest threat in the field is Kenyan Salina Kosgei, who won the Boston Marathon in the spring. But even with the prospect of Kosgei and a world-class field breathing down her neck, Radcliffe feels no pressure.

She added: "Leading up to this race is a lot like 2004 - another really tough year - and that year in New York I felt the strongest that I've felt in my career. On the way in on the bus for the race, I was laughing and joking and everyone else was just looking at me oddly.

"But the thing is I know how bad things can be, so I've said to myself that all I can really do is enjoy the race."

Victory on Sunday would still leave Radcliffe some way short of Grete Waitz, the Norwegian who won the race nine times.

And while the Briton would love to get as close to Grete's record as possible, her focus for 2010 is to get back winning in the UK in the build-up to London 2012. "I'd really love to run back at home," she added. "I've had London taken away from me a few times, in 2006, 2008 and again this year. It's an amazing race for me and I'd love to win there next season. That's a big goal, the big goal for 2010."

By 2012, Radcliffe will be 38 and knows her best chance of winning Olympic gold may well have past. In 2004, she pulled out of the race while last year she finished 23rd after a build-up disrupted by injury.

"The big goal is to win in London in 2012 but that depends on how my body holds up," she said.

* Paula Radcliffe was talking at a unique women's-only 10k in Victoria Park as part of the Nike+ Human Race 2009 on Sunday, which saw 250,000 runners across the world uniting to run their own perfect 10k on the same day. For more information, visit www.nikerunning.com