So there's no better place to erase the frustrations of the injuries and ailments that have sidelined her than the New York City Marathon on Sunday. Three times she has come in seeking to prove she remains at the top of her event, and three times she has won.

Still, the world record-holder would rather not keep repeating this cycle of discouragement-then-redemption. She makes no secret of planning to compete through 2012, when she could win that elusive Olympic gold medal in front of her fellow Brits at the London Games. Radcliffe won't rule out racing beyond that _ it just depends on whether her body lets her.

"It's that mental side, when you've done all the preparation and you can't make it to the starting line _ that's what kicks you in the teeth each time," she told The Associated Press on Thursday before speaking to local high school athletes at an event sponsored by Nike. "That will be what would make me say, 'I can't do this anymore.'"

Radcliffe planned to run the London Marathon and at the world championships this year, then undergo bunion surgery to alleviate nagging soreness in her right foot. But during her training for London, the pain became so bad she couldn't walk.

Radcliffe had the reconstructive surgery in March. She hoped to race at the worlds in August, running the NYC Half-Marathon the week before to test her readiness. But despite winning in New York, Radcliffe decided her foot wasn't quite ready for a marathon.

She then planned to enter the world half-marathon championships this month _ until tonsillitis kept her out.

Radcliffe feels confident going into the NYC Marathon. But she can imagine if she has too many setbacks in a row at some point in the future how that would wear on her _ and make her consider retirement.

"When it's one, and then you get four or five good races, and then it's one _ that's OK, you can deal with it," Radcliffe said. "Every athlete knows, especially in the marathon, that of 10 people trying to get to the start line, maybe only six will get there. Everybody knows that risk.

"But it's when for me it's been the last four in a row, that's when you have to stay strong and have really good support around you. You just need one good race, then it's like, 'OK, I can handle it now.' When it's one after another it starts to push you down."

New York, where Radcliffe is the two-time defending champ, always seems to be the site of that one good race. In 2004 and 2008, she rebounded from Olympic heartache with wins here. In 2007, she was victorious in her first marathon since the birth of her daughter less than 10 months earlier.

Isla is now almost 3, and Radcliffe hopes to give her a sibling soon _ in time to give Mum plenty of time to train for the 2012 games. Radcliffe said she'll be fine if she runs only two or three marathons between now and London.

The way she feels heading into Sunday's race is the way she always hopes to feel in the days leading up to a marathon.

"It's just nice to have the work done," she said, "and know you can stand on that starting line ready to go."