London 2012 has kept me going, says Paula Radcliffe

Women's marathon world record holder Paula Radcliffe has credited the 'carrot' of next year's London Olympics for keeping her going through the toughest year of her career. 

Radcliffe, who put her running on hold to have a second child and has struggled with a back injury, will enter her first marathon since 2009 when she competes in Berlin this month. 

"This year has been the hardest ever and if I didn't have London I might have given up," the 37-year-old told the BBC on Thursday.

"Having injury and illness is always difficult. When you are battling through and you've had a number of setbacks, you wonder if you can take one more. 

"But you get over it and get back to what you enjoy about running and the racing and put it behind you," added the Briton, who set her world record time in London in 2003. 

"I'd (have) been lying if I said I didn't contemplate giving up, especially when you suffer more and more setbacks. 

"I did have a couple of weeks of thinking I wasn't going to do it any more but then a couple of days later I was back and decided I wanted to try and do it... you have the carrot of London in 2012 and that is what I am working towards."

The Berlin Marathon is on Sept. 25.