Dibaba, Dvorak out

Dibaba pulled out of the women's 5,000 metres with stomach pain, ending her bid for a second consecutive distance double.

Dibaba, whose gripping come-from-behind 10,000m win has been a highlight of the world championships, had earlier warned that she was in doubt.

Ethiopia will now be represented by the formidable trio of Meseret Defar, Meselech Melkamu and Gelete Burka.

"I am confident that Meseret, Gelete and Meselech will run very well," said Dibaba through a statement issued by the Ethiopian Athletics Federation.

On Saturday, Dibaba became the first woman to defend the 10,000m title and was on course for a unique double double -- 5,000m and 10,000m at consecutive world championships.

But she has long been troubled by stomach cramps on her right side and fought through the pain barrier as she battled back from last in the 10,000m.

"I've had cramps on and off since I ran cross-country last year so I want to see how it is. It bothered me in the 10,000m and I can still feel it," she told reporters earlier.

"I've already got four gold medals in the world championships and the pain is really going to be the thing that I'm going to decide on after training."

Dibaba's withdrawal opens the door for fierce rival Defar, the Olympic champion and world record-holder.

"If Tirunesh had been in competition it would have been tougher," Defar said.

Dibaba's first world title was over 5,000m in 2003. On Saturday, she stumbled to 50m behind but showed astonishing grit to recover for the win.

Three times world decathlon champion Tomas Dvorak has has a nagging heel injury.

The Czech's attempts to take part in his eighth world championship were dashed after an ultrasonic scan showed no improvement to the injury, team doctor Milos Barna told the Czech news agency CTK. "That is why we have decided that he will not compete," he added.

The 35-year-old, who took the world title in 1997, 1999 and 2001, first suffered the pain when competing at a meeting at Kladno, on the outskirts of Prague, in June.

The injury returned to haunt him last week after he had flown out to Japan.

The competition for the decathalon world title is due to take place on Friday and Saturday.

Dvorak, who has already taken part in seven previous world championships, said in April that this one would be his last. "You can not stop time," the former world points record holder declared.