Australia's Sally Pearson crosses the finish line for a gold medal win in the women's 100-meter hurdles final during the athletics in the Olympic Stadium at the 2012 Summer Olympics, London, Tuesday, Aug. 7, 2012. (AP Photo/Mark Baker)

Australia's Sally Pearson reacts as she wins gold in the women's 100-meter hurdles final during the athletics in the Olympic Stadium at the 2012 Summer Olympics, London, Tuesday, Aug. 7, 2012. (AP Photo/David J. Phillip)

China's Liu Xiang kisses his hurdle after falling in a men's 110-meter hurdles heat during the athletics in the Olympic Stadium at the 2012 Summer Olympics, London, Tuesday, Aug. 7, 2012.(AP Photo/Martin Meissner)

In this combination of three photos, China's Liu Xiang, second left, falls during a men's 110-meter hurdles heat during the athletics in the Olympic Stadium at the 2012 Summer Olympics, London, Tuesday, Aug. 7, 2012. Competing with Liu are from left to right: Poland's Artur Noga, Hungary's Balazs Baji, and Barbados' Shane Brathwaite. (AP Photo/Daniel Ochoa De Olza)

Jamaica's Usain Bolt competes in a men's 200-meter heat during the athletics in the Olympic Stadium at the 2012 Summer Olympics, London, Tuesday, Aug. 7, 2012. (AP Photo/Matt Dunham)

Great Britain's Alistair Brownlee, top, is congratulated by Spain's Javier Gomez after Brownlee won the gold medal in the men's triathlon at the 2012 Summer Olympics, Tuesday, Aug. 7, 2012, in London. Gomez took the silver. (AP Photo/Darron Cummings)

This picture taken with a fisheye lens shows France's Benjamin Compaore participating in the men's triple jump qualifying round during the athletics in the Olympic Stadium at the 2012 Summer Olympics, London, Tuesday, Aug. 7, 2012. (AP Photo/David J. Phillip)

U.S. gymnast Gabrielle Douglas loses her balance and hangs onto the balance beam during the artistic gymnastics women's apparatus finals at the 2012 Summer Olympics, Tuesday, Aug. 7, 2012, in London. (AP Photo/Julie Jacobson)

A tattoo of the Olympic Rings and the letters USA are partly visible as U.S. gymnast Jonathan Horton stretches his muscles during the artistic gymnastics men's apparatus finals at the 2012 Summer Olympics, Tuesday, Aug. 7, 2012, in London. (AP Photo/Julie Jacobson)

Germany's Robert Harting celebrates his gold medal win in the men's discus during the athletics in the Olympic Stadium at the 2012 Summer Olympics, London, Tuesday, Aug. 7, 2012. (AP Photo/Matt Slocum)

Matthias Steiner of Germany gets hit by the weights while failing to make a successful lift in the men's over 105-kg, group A, weightlifting competition at the 2012 Summer Olympics, Tuesday, Aug. 7, 2012, in London. (AP Photo/Ng Han Guan)

United States' Destinee Hooker spins the ball in her hand as she prepares to serve during a women's quarterfinal volleyball match against the Dominican Republic at the 2012 Summer Olympics, Tuesday, Aug. 7, 2012, in London. (AP Photo/Jeff Roberson)

Dorian Van Rijsselberge of Netherlands celebrates his gold medal of the RS:X race at the London 2012 Summer Olympics, Tuesday, Aug. 7, 2012, in Weymouth and Portland, England. (AP Photo/Francois Mori)

Kerri Walsh Jennings of the United States leaps in the air after beating China in two sets during a women's semi-final beach volleyball match at the 2012 Summer Olympics, Tuesday, Aug. 7, 2012, in London. (AP Photo/Dave Martin)

Mexico's Javier Cortes (7) celebrates his goal with teammates Raul Jimenez, left, Jorge Enriquez and Darvin Chavez during their men's soccer semifinal match against Japan at Wembley Stadium at the 2012 Summer Olympics, Tuesday, Aug. 7, 2012, in London. (AP Photo/Luca Bruno)

Britain's Laura Trott adjusts her helmet during the track cycling events at the 2012 Summer Olympics in London, Tuesday, Aug. 7, 2012. (AP Photo/Christophe Ena)

Frederic Fokejou Tefot of Cameroon competes in the men's +105-kg, group B, weightlifting competition at the 2012 Summer Olympics, Tuesday, Aug. 7, 2012, in London. (AP Photo/Mike Groll)