Men's and women's Pentathlon

( Steve Bardens )

MEN

Key Dates: Aug. 11

Venues: Copper Box (fencing); Aquatic Centre (swimming); Greenwich Park (running, riding, shooting).

Big story: Four of the top five-ranked men are Russian, but only two can go to the Olympics. Andrei Moiseev is the 2011 world champion and Aleksander Lesun is the 2012 world champion. If there's not a Russian on the medal podium, huge upsets have happened.

Top U.S. prospect: Dennis Bowsher, an Olympic rookie who narrowly missed making the Beijing team, is the only U.S. representative and is ranked 49th in the world.

Others to watch: The only non-Russian in the world top five is Adam Marosi of Hungary. Woojin Hwang of South Korea has also been on the podium at the last two world championships.

Little-known fact: Only Lars Hall of Sweden (1952 and 1956) and Moiseev (2004 and 2008) have won two Olympic gold medals. Moiseev would stand alone if he wins his third gold in London.

WOMEN

Key dates: Aug. 12

Venues: Copper Box (fencing); Aquatic Centre (swimming); Greenwich Park (running, riding, shooting).

Big story: Mhairi Spence was one of four British women who qualified for Beijing, but the country could only send two and Spence was left home. She won the 2012 world championships though and will have strong support.

Top U.S. prospect: Margaux Isaksen has been slowed this year while suffering from mononucleosis. She is only 20 and already in her second Olympics.

Others to watch: Lithuania's Laura Asadauskaite leads the world rankings, and China's Qian Chen finished second at the most recent world championships.

Little-known fact: The women's sport entered the Olympics in 2000, and Elena Rublevska of Latvia, who has qualified, will become the only woman to have competed in all four Olympics if she starts in London.