Kerron Clement (L, back), Angelo Taylor and LaShawn Merritt (2R) of the U.S. celebrate their victory next to second placed Britain's Martyn Rooney, Robert Tobin, Conrad Williams and Michael Bingham (3L-R) in the men's 4x400 metres relay final during the world athletics championships at the Olympic stadium in Berlin, August 23, 2009, REUTERS/Tobias Schwarz (GERMANY) 

Angelo Taylor, Kerron Clement and LaShawn Merritt of the U.S. celebrate their victory next to second placed Britain's Martyn Rooney, Robert Tobin (covered), Conrad Williams and Michael Bingham (L-R) in the men's 4x400 metres relay final during the world athletics championships at the Olympic stadium in Berlin, August 23, 2009, REUTERS/Tobias Schwarz (GERMANY) 

Jeremy Wariner of the U.S. (R) passes the baton to team mate Kerron Clement the 4x400 meters relay final during the world athletics championships at the Olympic stadium in Berlin, August 23, 2009. REUTERS/Dominic Ebenbichler (GERMANY SPORT ATHLETICS) 

Jeremy Wariner of the U.S. (R) passes the baton to team mate Kerron Clement the 4x400 meters relay final during the world athletics championships at the Olympic stadium in Berlin, August 23, 2009. REUTERS/Dominic Ebenbichler (GERMANY SPORT ATHLETICS) 

Britain's Martyn Rooney, Conrad Williams, Robert Tobin and Michael Bingham (3L-R) celebrate after placing second next to gold medal winners Kerron Clement (L) and LaShawn Merritt of the U.S. in the men's 4x400 metres relay final during the world athletics championships at the Olympic stadium in Berlin, August 23, 2009, REUTERS/Max Rossi (GERMANY) 

Kerron Clement of the U.S. passes the baton to team mate LaShawn Merritt (R) in the 4x400 meters relay final during the world athletics championships at the Olympic stadium in Berlin, August 23, 2009. REUTERS/Tobias Schwarz (GERMANY SPORT ATHLETICS) 

Javier Culson of Puerto Rico, Kerron Clement of the U.S. and compatriot Bershawn Jackson (L-R) display their medals during the awards ceremony for the men's 400 metres hurdles at the world athletics championships at the Olympic stadium in Berlin August 19, 2009. Clement won the gold, ahead of Culson who won silver and Jackson who won bronze. REUTERS/Wolfgang Rattay (GERMANY SPORT ATHLETICS) 

Kerron Clement of the U.S. displays his gold medal during the awards ceremony for the men's 400 metres hurdles at the world athletics championships at the Olympic stadium in Berlin August 19, 2009. Kerron Clement of the U.S. won the gold, ahead of Javier Culson of Puerto Rico who won silver and Bershawn Jackson of the U.S.who won bronze. REUTERS/Wolfgang Rattay (GERMANY) 

Kerron Clement of the U.S. bites his gold medal during the awards ceremony for the men's 400 metres hurdles at the world athletics championships at the Olympic stadium in Berlin August 19, 2009. Kerron Clement of the U.S. won the gold, ahead of Javier Culson of Puerto Rico who won silver and Bershawn Jackson of the U.S.who won bronze. REUTERS/Wolfgang Rattay (GERMANY) 

Javier Culson of Puerto Rico bites his silver medal during the awards ceremony for the men's 400 metres hurdles at the world athletics championships at the Olympic stadium in Berlin August 19, 2009. Kerron Clement of the U.S. won the gold, ahead of Culson who won silver and Bershawn Jackson of the U.S.who won bronze. REUTERS/Wolfgang Rattay (GERMANY) 

Kerron Clement of the U.S. celebrates with his country's flag after he won the men's 400 meters hurdles final during the world athletics championships at the Olympic stadium in Berlin, August 18, 2009. REUTERS/Max Rossi (GERMANY) 

Kerron Clement of the U.S. celebrates with his country's flag after he won the men's 400 meters hurdles final during the world athletics championships at the Olympic stadium in Berlin, August 18, 2009. REUTERS/Tobias Schwarz (GERMANY) 

Kerron Clement (L) of the U.S. is congratulated by Felix Sanchez of Dominican Republic after he won the men's 400 meters hurdles final during the world athletics championships at the Olympic stadium in Berlin, August 18, 2009. REUTERS/Tobias Schwarz (GERMANY) 

Kerron Clement of the U.S. celebrates next to David Greene of Britain (L) as he won the men's 400 meters hurdles final during the world athletics championships at the Olympic stadium in Berlin August 18, 2009. REUTERS/Phil Noble (GERMANY SPORT ATHLETICS) 

Kerron Clement of the U.S. is congratulated by Javier Culson of Puerto Rico (L) as he won the men's 400 meters hurdles final during the world athletics championships at the Olympic stadium in Berlin August 18, 2009. REUTERS/Michael Dalder (GERMANY SPORT ATHLETICS) 

Kerron Clement (3R) of the U.S. crosses the finish line to win the men's 400 meters hurdles final during the world athletics championships at the Olympic stadium in Berlin, August 18, 2009. REUTERS/Tobias Schwarz (GERMANY) 

Kerron Clement (L) of the U.S. is congratulated by Felix Sanchez of Dominican Republic after he won the men's 400 meters hurdles final during the world athletics championships at the Olympic stadium in Berlin, August 18, 2009. REUTERS/Phil Noble (GERMANY) 

Kerron Clement (L) of the U.S. is congratulated by Felix Sanchez of Dominican Republic after he won the men's 400 meters hurdles final during the world athletics championships at the Olympic stadium in Berlin, August 18, 2009. REUTERS/Phil Noble (GERMANY) 

Kerron Clement (C) of the U.S. crosses the finish line to win the men's 400 meters hurdles final ahead of Jehue Gordon of Trinidad and Tobago and Felix Sanchez (L) of Dominican Republic during the world athletics championships at the Olympic stadium in Berlin, August 18, 2009. REUTERS/Michael Dalder (GERMANY) 

Kerron Clement of the U.S.celebrates after he won the men's 400 meters hurdles final during the world athletics championships at the Olympic stadium in Berlin, August 18, 2009. REUTERS/Dominic Ebenbichler (GERMANY) 

Kerron Clement of the U.S. (2nd R) clears a hurdle in front of compatriot Bershawn Jackson (L), Felix Sanchez of Dominican Republic (2nd L) and Jehue Gordon of Trinidad and Tobago as he run to win the men's 400 meters hurdles final during the world athletics championships at the Olympic stadium in Berlin August 18, 2009. REUTERS/Max Rossi (GERMANY SPORT ATHLETICS) 

Kerron Clement (R) of the U.S. and Felix Sanchez of Dominican Republic compete in the men's 400 meters hurdles final during the world athletics championships at the Olympic stadium in Berlin, August 18, 2009. REUTERS/Wolfgang Rattay (GERMANY) 

Kerron Clement of the U.S. clears a hurdle in front of Felix Sanchez of Dominican Republic (L) as he run to win the men's 400 meters hurdles final during the world athletics championships at the Olympic stadium in Berlin August 18, 2009. REUTERS/Tobias Schwarz (GERMANY SPORT ATHLETICS) 

Kerron Clement (L) of the U.S. is congratulated by Felix Sanchez of Dominican Republic after he won the men's 400 meters hurdles final during the world athletics championships at the Olympic stadium in Berlin, August 16, 2009. REUTERS/Phil Noble (GERMANY) 

Kerron Clement (L) of the U.S. is congratulated by Felix Sanchez of Dominican Republic after he won the men's 400 meters hurdles final during the world athletics championships at the Olympic stadium in Berlin, August 16, 2009. REUTERS/Phil Noble (GERMANY) 

Kerron Clement of the U.S. celebrates as he won the men's 400 meters hurdles final during the world athletics championships at the Olympic stadium in Berlin August 18, 2009. (GERMANY SPORT ATHLETICS) REUTERS/Tobias Schwarz (GERMANY SPORT ATHLETICS) 

Kerron Clement (C) of the U.S. crosses the finish line to win the men's 400 meters hurdles final ahead of Jehue Gordon of Trinidad and Tobago and Felix Sanchez (L) of Dominican Republic during the world athletics championships at the Olympic stadium in Berlin, August 16, 2009. REUTERS/Michael Dalder (GERMANY) 

Kerron Clement of the U.S. celebrates as he won the men?s 400 meters hurdles final during the world athletics championships at the Olympic stadium in Berlin August 18, 2009. (GERMANY SPORT ATHLETICS) REUTERS/Michael Dalder (GERMANY SPORT ATHLETICS) 

Kerron Clement of the U.S. reacts after winning his men's 400 meters hurdles semi-final round heat during the world athletics championships at the Olympic stadium in Berlin, August 16, 2009. REUTERS/Michael Dalder (GERMANY SPORT ATHLETICS) 

Kerron Clement (C) of the U.S. clears the final hurdle ahead of Danny McFarlane (L) of Jamaica and Andres Silva (R) of Uruguay in their men's 400 meters hurdles semi-final round heat during the world athletics championships at the Olympic stadium in Berlin, August 16, 2009. REUTERS/Michael Dalder (GERMANY SPORT ATHLETICS) 

Kerron Clement of the U.S. celebrates after winning in the men's 400 meters hurdles semi-final first heat during the world athletics championships at the Olympic stadium in Berlin, August 16, 2009. REUTERS/Tobias Schwarz (GERMANY SPORT ATHLETICS) 

Kerron Clement of the U.S. clears a hurdle in the men's third heats 400 metres hurdles event during the world athletics championships at the Olympic stadium in Berlin, August 15, 2009. REUTERS/Max Rossi (GERMANY) 

Jehue Gordon of Trinidad and Tobago, Felix Sanchez of Dominican Republic, Danny McFarlane of Jamaica and Kerron Clement of the U.S. (L-R) clear hurdles in the men's third heats 400 metres hurdles event during the world athletics championships at the Olympic stadium in Berlin, August 15, 2009. REUTERS/Tobias Schwarz (GERMANY) 

Kerron Clement of the U.S. (R) and Danny McFarlane of Jamaica (L) clear a hurdle in the men's 400 metres hurdles third heat during the world athletics championships at the Olympic stadium in Berlin, August 15, 2009. REUTERS/Tobias Schwarz (GERMANY SPORT ATHLETICS) 

Kerron Clement of the U.S. competes in the men's third heats 400 metres hurdles event during the world athletics championships at the Olympic stadium in Berlin, August 15, 2009. REUTERS/Phil Noble (GERMANY) 

Kerron Clement of the U.S. celebrates as he wins the men's 400m hurdles race during the London Grand Prix athletics tournament at Crystal Palace in London July 25, 2009. REUTERS/Dylan Martinez (BRITAIN SPORT ATHLETICS) 

Kerron Clement of the U.S. (C) clears the final hurdle on his way to win the men's 400m hurdles race during the London Grand Prix athletics tournament at Crystal Palace in London July 25, 2009. REUTERS/Dylan Martinez (BRITAIN SPORT ATHLETICS) 

Kerron Clement of the U.S. celebrates as he wins the men's 400m hurdles race during the London Grand Prix athletics tournament at Crystal Palace in London July 25, 2009. REUTERS/Dylan Martinez (BRITAIN SPORT ATHLETICS) 

Isa Phillips of Jamaica (L) and Kerron Clement of the U.S.clear a hurdle in the men's 400 metres race during the Super Grand Prix athletics meeting at the Stade Olympique in Lausanne July 7, 2009. REUTERS/Ruben Sprich (SWITZERLAND SPORT ATHLETICS) 

LaShawn Merritt (C) win the men's 400 meter race ahead of Gil Roberts (L), who finished in second and Kerron Clement, who finished third at the U.S. track and field championships in Eugene, Oregon June 27, 2009.REUTERS/Richard Clement(UNITED STATES SPORT ATHLETICS) 

Kerron Clement of the U.S. (R) competes to win the men's 400 metres hurdles event next to Jamaica's Danny McFarlane at the IAAF World Athletics Final in Stuttgart September 13, 2008. REUTERS/Michaela Rehle (GERMANY) 

Kerron Clement of the U.S. celebrates after winning the men's 400 metres hurdles event at the IAAF World Athletics Final in Stuttgart September 13, 2008. REUTERS/Michaela Rehle (GERMANY) 

Kerron Clement of the US (2nd L) clears a hurdle on his way to winning the men's 400m hurdles race ahead of Danny McFarlane of Jamaica (2nd R) in the IAAF Golden League Memorial Van Damme athletics meeting in Brussels September 5, 2008. REUTERS/Sebastien Pirlet (BELGIUM) 

Kerron Clement of the US (L) wins the men's 400m hurdles race in the IAAF Golden League Memorial Van Damme athletics meeting in Brussels September 5, 2008. REUTERS/Sebastien Pirlet (BELGIUM) 

Regi Witherspoon of the U.S. (front) receives the baton from his teammate Kerron Clement (R) during their men's 4 x 400m relay heat of the athletics competition in the National Stadium at the Beijing 2008 Olympic Games August 22, 2008. (From L to R) Arnaud Ghislain and Jonathan Borlee of Belgium, John Steffensen and Mark Ormrod of Australia, and Alwyn Myburgh and Ofentse Mogawane of South Africa are seen with them. REUTERS/David Gray (CHINA)

Men's 400m hurdles medallists (L-R) Kerron Clement of the U.S. (silver) and compatriots Angelo Taylor (gold) and Bershawn Jackson (bronze) pose on the podium during the medal's ceremony of the athletics competition in the Beijing 2008 Olympic Games at the National Stadium August 19, 2008. REUTERS/Mike Blake (CHINA) 

Winner Angelo Taylor of the U.S. (R) celebrates with team-mates, second-placed Kerron Clement (L) and third-placed Bershawn Jackson (C) , after the men's 400m hurdles final of the athletics competition in the National Stadium at the Beijing Olympic Games August 18, 2008. REUTERS/Dylan Martinez (CHINA)

Angelo Taylor of the U.S. clears a hurdle on his way to winning the men's 400m hurdles final of the athletics competition in the National Stadium at the Beijing Olympic Games August 18, 2008. Taylor's team-mates Kerron Clement (2nd R) and Bershawn Jackson (L) finished second and third respectively. REUTERS/Mike Blake (CHINA)

Winner Angelo Taylor of the U.S. celebrates with team-mates, second-placed Kerron Clement (R) and third-placed Bershawn Jackson (L) , after the men's 400m hurdles final of the athletics competition in the National Stadium at the Beijing Olympic Games August 18, 2008. REUTERS/Dylan Martinez (CHINA) 

Angelo Taylor of the U.S. gestures as he wins the men's 400m hurdles final of the athletics competition in the National Stadium at the Beijing 2008 Olympic Games August 18, 2008. Taylor's compatriot Bershawn Jackson (L), who finished third, and Kerron Clement (R), who finished second, and Danny Mcfarlane of Jamaica (2nd R)are seen with Taylor. REUTERS/Gary Hershorn (CHINA) 

Kerron Clement of the U.S. clears a hurdle during their men's 400m hurdles semi-final of the athletics competition at the Beijing 2008 Olympic Games in the National Stadium, August 16, 2008. REUTERS/Wolfgang Rattay (CHINA)

Kerron Clement of the U.S. (7) and Periklis Iakovakis of Greece clear a hurdle during their men's 400m hurdles semi-final of the athletics competition at the Beijing 2008 Olympic Games in the National Stadium, August 16, 2008. REUTERS/Hans Deryk (CHINA) 

Kerron Clement of the U.S. (L) rests in front of Alwyn Myburgh of South Africa after their men's 400m hurdles semi-final of the athletics competition at the Beijing 2008 Olympic Games in the National Stadium, August 16, 2008. REUTERS/Gary Hershorn (CHINA)

Kerron Clement of the U.S. (L) and Periklis Iakovakis of Greece clear a hurdle during their men's 400m hurdles semi-final of the athletics competition at the Beijing 2008 Olympic Games in the National Stadium, August 16, 2008. REUTERS/Gary Hershorn (CHINA) 

Kerron Clement of the U.S. starts his men's 400m hurdles heat during the athletics competition in the National Stadium at the Beijing 2008 Olympic Games August 15, 2008 REUTERS/Gary Hershorn (CHINA) 

Dai Tamesue of Japan (front L) and Kerron Clement of the U.S. (front R) clear a hurdle in front of Felix Sanchez of the Dominican Republic (back L) and Mowen Boino of Papua New Guinea during their men's 400m hurdles heat in the athletics competition of the Beijing 2008 Olympic Games at the National Stadium, August 15, 2008. REUTERS/Mike Blake (CHINA)

Periklis Iakovakis of Greece (L), Dai Tamesue of Japan (C) and Kerron Clement of the U.S. clear a hurdle during their men's 400m hurdles heat in the athletics competition of the Beijing 2008 Olympic Games at the National Stadium, August 15, 2008. REUTERS/David Gray (CHINA)

Dai Tamesue of Japan (L) clears a hurdle beside Kerron Clement of the U.S. during their men's 400m hurdles heat in the athletics competition of the Beijing 2008 Olympic Games at the National Stadium, August 15, 2008. REUTERS/Hans Deryk (CHINA)

Kerron Clement of the U.S. talks to reporters after his 400 metre hurdles practice session for the upcoming Beijing 2008 Olympic Games, in Dalian August 4, 2008. REUTERS/Kim Kyung-Hoon (CHINA) 

Kerron Clement of the U.S. smiles as he crosses the finish line to win the 400 metres hurdles during the London Grand Prix at Crystal Palace in London July 26, 2008. REUTERS/Andrew Winning (BRITAIN)