Britain's Jessica Ennis celebrates winning gold following the 800-meter heptathlon as she and other athletes complete a victory lap during the athletics in the Olympic Stadium at the 2012 Summer Olympics, London, Saturday, Aug. 4, 2012. (AP Photo/Kirsty Wigglesworth)

Britain's Jessica Ennis reacts winning gold following the 800-meter heptathlon during the athletics in the Olympic Stadium at the 2012 Summer Olympics, London, Saturday, Aug. 4, 2012. (AP Photo/Kirsty Wigglesworth)

Britain's Jessica Ennis lands a jump during the long jump heptathlon during the athletics in the Olympic Stadium at the 2012 Summer Olympics, London, Saturday, Aug. 4, 2012. (AP Photo/Lee Jin-man)

Jamaica's Shelly-Ann Fraser-Pryce, second from left, crosses the finish line to win gold ahead of United States' Carmelita Jeter, third from right, Jamaica's Veronica Campbell-Brown, second from right, Trinidad's Kelly-Ann Baptiste, right, Ivory Coast's Murielle Ahoure, third from left, and Nigeria's Blessing Okagbare, left, in the women's 100-meter final during the athletics in the Olympic Stadium at the 2012 Summer Olympics, London, Saturday, Aug. 4, 2012. (AP Photo/Matt Dunham)

Switzerland's Nicola Spirig, middle, Sweden's Lisa Norden, right, and Australia's Erin Densham react after finishing the triathlon at the 2012 Summer Olympics, Saturday, Aug. 4, 2012, in London. Spirig won the gold medal. Norden took the silver and Densham the bronze. (AP Photo/Charlie Riedel)

Switzerland's Nicola Spirig, right, finishes ahead of Sweden's Lisa Norden to win the gold medal in the women's triathlon at the 2012 Summer Olympics, Saturday, Aug. 4, 2012, in London. Norden took the silver. (AP Photo/Charlie Riedel)

New Zealand's Nicky Samuels dives into the water for the start of the triathlon at the 2012 Summer Olympics, Saturday, Aug. 4, 2012, in London. (AP Photo/Jae C. Hong)

United States' Michael Phelps throws flowers to his mother Debbie after the men's 4 X 100-meter medley relay at the Aquatics Centre in the Olympic Park during the 2012 Summer Olympics, London, Saturday, Aug. 4, 2012. (AP Photo/Jae C. Hong)

United States' swimmer Michael Phelps poses with his gold medal in the men's 4 x 100-meter medley relay at the Aquatics Centre in the Olympic Park during the 2012 Summer Olympics in London, Saturday, Aug. 4, 2012. (AP Photo/Michael Sohn)

Gold medallist, Chen Ding, from China, walks past a mister as he competes in the men's 20-kilometer race walk near Buckingham Palace at the 2012 Summer Olympics on Saturday, Aug. 4, 2012, in London. (AP Photo/Charlie Riedel)

Athletes compete in the men's 20-kilometer race walk near Buckingham Palace during the 2012 Summer Olympics Saturday, Aug. 4, 2012, in London. (AP Photo/Charlie Riedel)

Athletes compete in the 20-kilometer race walk at the 2012 Summer Olympics, Saturday, Aug. 4, 2012, in London. (AP Photo/Markus Schreiber)

USA's Lebron James (6) signals after scoring with a three point basket during a preliminary men's basketball game against Lithuania at the 2012 Summer Olympics, Saturday, Aug. 4, 2012, in London. (AP Photo/Eric Gay)

South Africa's Oscar Pistorius competes in a men's 400-meter heat during the athletics in the Olympic Stadium at the 2012 Summer Olympics, London, Saturday, Aug. 4, 2012. (AP Photo/Daniel Ochoa De Olza)

China's Fu Haifeng, left, and Cai Yun celebrate after beating Koo Kien Keat and Tan Boon Heong, of Malaysia, in a men's doubles badminton semifinal match at the 2012 Summer Olympics, Saturday, Aug. 4, 2012, in London. (AP Photo/Andres Leighton)

In this photo taken with a fisheye lens, Denmark's Caroline Bonde Holm competes in a women's pole vault qualification round during the athletics in the Olympic Stadium at the 2012 Summer Olympics, London, Saturday, Aug. 4, 2012. (AP Photo/David J. Phillip )

Britain's Mo Farah, right, crosses the finish line to win gold ahead of United States' Galen Rupp in the men's 10,000-meter final during the athletics in the Olympic Stadium at the 2012 Summer Olympics, London, Saturday, Aug. 4, 2012. (AP Photo/Anja Niedringhaus)

China's Sun Yang celebrates his gold medal win in the in the men's 1500-meter freestyle swimming final at the Aquatics Centre in the Olympic Park during the 2012 Summer Olympics in London, Saturday, Aug. 4, 2012. (AP Photo/Michael Sohn)

Joseph O'Regan of Britain, left, attempts to grasp the ball from Balazs Harai of Hungary during their men's water polo preliminary round match at the 2012 Summer Olympics, Saturday, Aug. 4, 2012, in London. (AP Photo/Alastair Grant)

San Marino's Alessandra Perilli ejects a spent cartridge after shooting during the women's trap final, at the 2012 Summer Olympics, Saturday, Aug. 4, 2012, in London. (AP Photo/Rebecca Blackwell)

Serena Wiiliams of the United States reacts during her match against Maria Sharapova of Russia at the All England Lawn Tennis Club in Wimbledon, London at the 2012 Summer Olympics, Saturday, Aug. 4, 2012. (AP Photo/Elise Amendola)

Jamaica's Usain Bolt gestures before competing in a men's 100-meter heat during the athletics in the Olympic Stadium at the 2012 Summer Olympics, London, Saturday, Aug. 4, 2012. (AP Photo/Matt Slocum)

Lisen Fredricson, of Sweden, falls off her horse Matrix during the equestrian individual show jumping competition at the 2012 Summer Olympics, Saturday, Aug. 4, 2012, in London. (AP Photo/David Goldman)

Tania Cagnotto of Italy dives during the women's 3-meter springboard diving semifinals in the Olympic Park during the 2012 Summer Olympics in London, Saturday, Aug. 4, 2012. (AP Photo/Mark J. Terrill)

Great Britain's Katherine Copeland cries during the award ceremony for the lightweight women's rowing double sculls after winning the gold medal in Eton Dorney, near Windsor, England, at the 2012 Summer Olympics, Saturday, Aug. 4, 2012. (AP Photo/Natacha Pisarenko)