RIO DE JANEIRO (AP) It's dynasty time on the opening two days of track and field at the Olympics.
As of Friday morning, three athletes will each try to become the first woman to win three straight individual titles at the Summer Games.
New Zealand shot putter Valerie Adams stands the best chance, while the odds don't look that great for 10,000-meter great Tirunesh Dibaba and 100-meter sprinter Shelly-Ann Fraser-Pryce. And if none of the three succeed, there still is Czech javelin double champion Barbora Spotakova on Aug. 18.
Here is a look what opposition and odds they face Friday and Saturday:
VALERIE ADAMS/SHOT PUT - She knows how to fight back. Two years ago, after being basically untouchable at major championships from 2007 to 2014, with four world and two Olympic gold medals to show for it, she underwent elbow and shoulder surgery. It is tough enough to return, but to come back with another Olympic gold would be outstanding.
Recovery didn't come easy as the tall New Zealander struggled until early this year. Slowly though, she found her groove again and has championship experience. ''My preparations have been going really well,'' she said as she arrived in Brazil from her training base in Switzerland.
Adams is the second-best performer of the season, behind China's Gong Lijiao. Christina Schwanitz of Germany, who took over Adams' world title last year, could well be her toughest opponent on Friday.
Adams knows how elusive Olympic gold can be. The London Games four years ago were already over when gold medalist Nadezhda Ostapchuk was caught for doping and Adams belatedly won her second title. This weekend, she wants to hold her third gold in the Olympic Stadium.
TIRUNESH DIBABA/10,000 - Dibaba is already considered the greatest female distance runner in history with her five Olympic medals (three gold) and five world championship golds. The 31-year-old has fought back from major injuries several times in her career and just finished a yearlong break after the birth of her son.
Dibaba's toughest opposition is likely to come from fellow Ethiopian Almaz Ayana, 24, who is doing the long-distance double in Rio after winning the 5,000 meters at the world championship last year and has the top 10,000-meter performance of the year so far.
Dibaba is a massive celebrity in Ethiopia and leads a family of runners, including sisters Genzebe, who will compete in the 1,500 meters, and Ejegayehu, who won silver in the 10,000 meters in the 2004 Games.
SHELLY-ANN FRASER-PRYCE/100 - For years, sprinting was a U.S.-Jamaican duel, but Fraser-Pryce will also have to keep an eye on Dutchwoman Dafne Schippers, who was already breathing down her neck when the Jamaican won her third world title in Beijing last year. And a toe injury has hampered Fraser-Pryce this year.
Like Dibaba, she will need to heed her own compatriots. Eileen Thompson leads the charge with a season's top time of 10.70 seconds. Three Americans have all run faster than Fraser-Pryce this season. None however, has proven it at major championships.
Fraser-Pryce carried her nation's flag at the opening ceremony, with her long hair dyed yellow and green, colors in both the Jamaican and Brazilian flags.
MEN - Three men, all American, have won four individual golds in a row: Ray Ewry in the standing high and long jumps between 1900 and 1908; Al Oerter in the discus between 1956 and 1968; and Carl Lewis in the long jump between 1984 and 1996.
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