US and Ethiopians look early winners

The world's best sprinters will also be part of the opening action today with two rounds of the men's 100 metres. Medals will be awarded in the men's shot put and women's 10,000 metres.

Both events could result in medal sweeps with the US men strongest in the shot put and Ethiopia's runners dominant in the women's 10,000 metres.

It has been 28 years since a country swept the shot put medals, but US trio Adam Nelson, Reese Hoffa and Christian Cantwell have the skills to join their 1960 counterparts.

"I really think it's realistic. I give it a 50-50 chance," Hoffa told reporters at the US training camp in the northeast Chinese city of Dalian.

"I would love to be the class of Olympic athletes to sweep but everything has to go right," said Hoffa.

"If we don't go out there and hit the marks that we're supposed to hit then we don't dominate because there are a lot of quality European athletes."

Nelson, twice an Olympic silver medallist, reigns as the year's top thrower with a heave of 22.12 metres. World champion Hoffa is close behind at 22.10 with Cantwell the world indoor champion.

All three have personal bests superior to their closest competitor, Andrey Mikhnevich. The Belarussian has the year's third best throw, 22.00 metres, with Cantwell fourth at 21.76.

In the women's 10,000 metres, Ethiopian Tirunesh Dibaba is favoured to add an Olympic gold medal to her two world championship titles.

Dibaba demonstrated her fitness by setting a world record of 14:11.15 in the 5,000 metres in Oslo in June.

In what could be a tactical race, she is likely to receive support from her older sister Ejegayehu, the 2004 silver medallist, and fellow Ethiopian Mestawat Tufa.

Both could join Dibaba on the medals podium.

Other top candidates include Turkey's Elvan Abeylegesse, the world silver medallist, and the American duo of Kara Goucher and Shalane Flanagan.

Goucher claimed bronze at the 2007 world championships and Flanagan lowered the American record to 30:34.49 this year.

The first four events of the heptathlon are also on the programme along with qualifying in seven events - the men's 1,500 metres, 400 hurdles and hammer throw, and the women's 800 metres, 3,000 metres steeplechase, triple jump and discus.

The women's steeplechase is being contested for the first time at an Olympics.