ATHLETICS: Britain's two-time champion Paula Radcliffe has pulled out of this weekend's IAAF World Cross Country Championships in Brussels through injury.

Radcliffe injured her right hamstring during a training session last Sunday and immediately sought medical advice.

The result was Radcliffe, who won long-course titles in 2001 and 2002, was forced to withdraw.

"I went for my usual long run on Sunday morning and everything was okay," she said. "Then in the evening I went for a light run and felt a stiffening in my hamstring and knew I needed treatment."

Radcliffe lives in Loughborough and underwent treatment at the local UK Athletics high performance centre in a bid to make tomorrow's eight-kilometre race. The injury was responding well to treatment but a major problem remained.

Radcliffe added: "I found it impossible to run uphill and in a cross country race there will always be plenty of them. Now it's case of getting back into training. That should be shortly, as it isn't a serious injury."

It is another blow to the favourite for this year's Olympic marathon title. Following her world record win in last April's London marathon, Radcliffe missed last summer's world championships with a leg injury.

But she bounced back in the autumn with magnificent victories in a series of high-quality road races. The highlights were running the world's fastest-ever women's marathon in the Great North Run, then a fortnight later claiming a third IAAF world title over the distance.

Before last weekend, everything seemed to be back on course for Radcliffe to successfully challenge for another world cross country title. Then came this latest setback, which again sees her having to fight to continue the most vital preparations of her career, for Athens.