Gold medallist Liu Zige (C) of China poses with other medallists at the women's 200m butterfly victory ceremony during the World Swimming Championships at the Sant Jordi arena in Barcelona August 1, 2013. Spain's Mireia Belmonte Garcia (L) finished second in the event and took the silver medal, while Hungary's Katinka Hosszu finished third and took the bronze. REUTERS/Gustau Nacarino (SPAIN - Tags: SPORT SWIMMING)

Gold medallist Liu Zige (C) of China poses with other medallists at the women's 200m butterfly victory ceremony during the World Swimming Championships at the Sant Jordi arena in Barcelona August 1, 2013. Spain's Mireia Belmonte Garcia (L) finished second in the event and took the silver medal, while Hungary's Katinka Hosszu finished third and took the bronze. REUTERS/Albert Gea (SPAIN - Tags: SPORT SWIMMING)

Gold medalist China's Liu Zige poses with her medal at the women's 200m butterfly victory ceremony during the World Swimming Championships at the Sant Jordi arena in Barcelona August 1, 2013. REUTERS/Michael Dalder (SPAIN - Tags: SPORT SWIMMING)

China's Liu Zige reacts after winning the women's 200m butterfly final during the World Swimming Championships at the Sant Jordi arena in Barcelona August 1, 2013. REUTERS/Albert Gea (SPAIN - Tags: SPORT SWIMMING)

Gold medalist China's Liu Zige (C) poses with silver medalist Spain's Mireia Belmonte (L) and bronze medalist Hungary's Katinka Hosszu at the women's 200m butterfly victory ceremony during the World Swimming Championships at the Sant Jordi arena in Barcelona August 1, 2013. REUTERS/Michael Dalder (SPAIN - Tags: SPORT SWIMMING)

China's Liu Zige swims in the women's 200m butterfly final during the World Swimming Championships at the Sant Jordi arena in Barcelona August 1, 2013. REUTERS/Albert Gea (SPAIN - Tags: SPORT SWIMMING)

China's Liu Zige reacts after winning the women's 200m butterfly final during the World Swimming Championships at the Sant Jordi arena in Barcelona August 1, 2013. REUTERS/Michael Dalder (SPAIN - Tags: SPORT SWIMMING)

China's Liu Zige reacts after winning the women's 200m butterfly final during the World Swimming Championships at the Sant Jordi arena in Barcelona August 1, 2013. REUTERS/Michael Dalder (SPAIN - Tags: SPORT SWIMMING)

China's Liu Zige swims in the women's 200m butterfly semi-final during the World Swimming Championships at the Sant Jordi arena in Barcelona July 31, 2013. REUTERS/Albert Gea (SPAIN - Tags: SPORT SWIMMING)

Liu Zige of China competes in the women's 200m butterfly semi-final during the World Swimming Championships at the Sant Jordi arena in Barcelona July 31, 2013. REUTERS/Michael Dalder (SPAIN - Tags: SPORT SWIMMING)

China's Liu Zige is seen underwater as she swims in the women's 200m butterfly semi-final during the World Swimming Championships at the Sant Jordi arena in Barcelona July 31, 2013. REUTERS/Michael Dalder (SPAIN - Tags: SPORT SWIMMING)

China's Liu Zige is seen underwater as she swims in the women's 200m butterfly semi-final during the World Swimming Championships at the Sant Jordi arena in Barcelona July 31, 2013. REUTERS/Michael Dalder (SPAIN - Tags: SPORT SWIMMING)

Liu Zige of China competes in women's 200m butterfly heats during the World Swimming Championships at the Sant Jordi arena in Barcelona July 31, 2013. REUTERS/Albert Gea (SPAIN - Tags: SPORT SWIMMING)

Gold medallist Ilaria Bianchi (C) of Italy poses next to silver medallist Liu Zige (L) of China and bronze medallist Jemma Lowe of Britain during the award ceremony for the women's 100m butterfly final during the FINA World Swimming Championships in Istanbul December 16, 2012. REUTERS/Murad Sezer (TURKEY - Tags: SPORT SWIMMING)

China's Liu Zige swims in the women's 200m butterfly heats during the London 2012 Olympic Games at the Aquatics Centre July 31, 2012. REUTERS/Tim Wimborne (BRITAIN - Tags: SPORT SWIMMING OLYMPICS)

Britain's Jemma Lowe (L) and China's Liu Zige are seen underwater as they swim in the women's 200m butterfly heats during the London 2012 Olympic Games at the Aquatics Centre July 31, 2012. REUTERS/Michael Dalder (BRITAIN - Tags: SPORT SWIMMING OLYMPICS) 

Liu Zige of China competes in the women's 200m butterfly heats swimming event during the London 2012 Olympic Games at the Aquatics Centre July 31, 2012. REUTERS/Toby Melville (BRITAIN - Tags: OLYMPICS SPORT SWIMMING)

Silver medallist Ellen Gandy of Britain, gold medallist Jiao Liuyang of China and bronze medallist Liu Zige of China (L-R) pose with their medals for the women's 200m butterfly final at the 14th FINA World Championships in Shanghai July 28, 2011. REUTERS/David Gray (CHINA - Tags: SPORT SWIMMING AQUATICS) 

China's Jiao Liuyang (L) gestures while speaking to her compatriot Liu Zige after the women's 200m butterfly final at the 14th FINA World Championships in Shanghai July 28, 2011. Jiao won the event and Liu took third place. REUTERS/Christinne Muschi (CHINA - Tags: SPORT SWIMMING) 

China's Jiao Liuyang and Liu Zige (facing camera) hug after the women's 200m butterfly final at the 14th FINA World Championships in Shanghai July 28, 2011. Jiao won the event and Liu took third place. REUTERS/Christinne Muschi (CHINA - Tags: SPORT SWIMMING AQUATICS) 

China's Jiao Liuyang (L) and Liu Zige celebrate after the women's 200m butterfly final at the 14th FINA World Championships in Shanghai July 28, 2011. Jiao won the event and Liu took third place. REUTERS/David Gray (CHINA - Tags: SPORT SWIMMING AQUATICS) 

China's Jiao Liuyang and Liu Zige celebrate after the women's 200m butterfly final at the 14th FINA World Championships in Shanghai July 28, 2011. Jiao won the event and Liu took third place. REUTERS/David Gray (CHINA - Tags: SPORT SWIMMING AQUATICS) 

China's Liu Zige competes in the women's 200m butterfly heats at the 14th FINA World Championships in Shanghai July 27, 2011. REUTERS/Bobby Yip (CHINA - Tags: SPORT SWIMMING AQUATICS) 

China's Liu Zige competes in the women's 200m butterfly final at the East Asian Games in Hong Kong December 6, 2009. Liu won the gold medal. REUTERS/David Gray (CHINA SPORT SWIMMING) 

China's Liu Zige competes in the women's 200m butterfly final at the East Asian Games in Hong Kong December 6, 2009. Liu won the gold medal. REUTERS/David Gray (CHINA SPORT SWIMMING IMAGES OF THE DAY) 

China's Liu Zige competes in the women's 200m butterfly final at the East Asian Games in Hong Kong December 6, 2009. Liu won the gold medal. REUTERS/David Gray (CHINA SPORT SWIMMING) 

China's Liu Zige looks at the scoreboard after winning the women's 200m butterfly final at the East Asian Games in Hong Kong December 6, 2009. REUTERS/David Gray (CHINA SPORT SWIMMING) 

China's Liu Zige competes in the women's 200m butterfly final at the East Asian Games in Hong Kong December 6, 2009. Liu won the gold medal. REUTERS/David Gray (CHINA SPORT SWIMMING) 

China's Liu Zige competes in the women's 200m butterfly final at the East Asian Games in Hong Kong December 6, 2009. Liu won the gold medal. REUTERS/David Gray (CHINA SPORT SWIMMING) 

Liu Zige of China reacts after setting a new world record in the women's 200m butterfly finals at the swimming World Cup in Berlin November 15, 2009. REUTERS/Wolfgang Rattay (GERMANY - Tags: SPORT SWIMMING) 

Liu Zige of China swims to set a new world record in the women's 200m butterfly finals at the swimming World Cup in Berlin November 15, 2009. REUTERS/Wolfgang Rattay (GERMANY - Tags: SPORT SWIMMING) 

Liu Zige of China swims to set a new world record in the women's 200m butterfly finals at the swimming World Cup in Berlin November 15, 2009. REUTERS/Wolfgang Rattay (GERMANY - Tags: SPORT SWIMMING) 

Liu Zige of China reacts after winning in the women's 200 metres butterfly finals at the swimming World Cup in Berlin, November 15, 2009. REUTERS/Tobias Schwarz (GERMANY - Tags: SPORT SWIMMING) 

Liu Zige of China competes to win in the women's 200 metres butterfly finals at the swimming World Cup in Berlin, November 15, 2009. REUTERS/Tobias Schwarz (GERMANY - Tags: SPORT SWIMMING) 

Liu Zige of China swims in the women's 200m butterfly heats at the swimming World Cup in Berlin November 15, 2009. REUTERS/Wolfgang Rattay (GERMANY - Tags: SPORT SWIMMING) 

Silver medallist Liu Zige of China poses on the podium after the men's 200m butterfly swimming final at the World Championships in Rome July 30, 2009. REUTERS/Alessandro Bianchi (ITALY SPORT SWIMMING) 

Silver medallist Liu Zige of China celebrates on the podium after the women's 200m butterfly swimming final at the World Championships in Rome July 30, 2009. REUTERS/Wolfgang Rattay (ITALY SPORT SWIMMING) 

Liu Zige of China competes in the women's 200m butterfly swimming final at the World Championships in Rome July 30, 2009. REUTERS/Stefano Rellandini (ITALY SPORT SWIMMING) 

Liu Zige of China competes in the women's 200m butterfly swimming semi-finals at the World Championships in Rome July 29, 2009. REUTERS/Tony Gentile (ITALY SPORT SWIMMING) 

Liu Zige of China poses with the gold medal after winning the women's 200 meters butterfly swimming final at the National Aquatics Center during the Beijing 2008 Olympic Games August 14, 2008. REUTERS/Jerry Lampen (CHINA) 

Liu Zige of China waves after receiving her gold medal for the women's 200m butterfly swimming final at the National Aquatics Center during the Beijing 2008 Olympic Games, August 14, 2008. REUTERS/Kai Pfaffenbach (CHINA) 

The women's 200m butterfly swimming final gold medal winner Liu Zige (R) of China and bronze medal winner Jessicah Schipper of Australia walk on the pool deck after the medal ceremony at the National Aquatics Center during the Beijing 2008 Olympic Games, August 14, 2008. REUTERS/Kai Pfaffenbach (CHINA) 

Gold medallist Liu Zige (C) of China stands with compatriot and silver medallist Jiao Liuyang (L) and bronze medallist Jessicah Schipper (R) of Australia after the women's 200 meters butterfly final at the National Aquatics Center during the Beijing 2008 Olympic Games August 14, 2008. REUTERS/Jerry Lampen (CHINA) 

Women's 200m butterfly gold medal winner Liu Zige (R) of China and silver medal winner Jiao Liuyang of China celebrate during the Beijing 2008 Olympic Games at the National Aquatics Centre, August 14, 2008. The stadium is also known as the Water Cube. REUTERS/David Gray (CHINA) 

Liu Zige of China holds her gold medal after winning the women's 200 meters butterfly swimming final at the National Aquatics Center during the Beijing 2008 Olympic Games August 14, 2008. REUTERS/Wolfgang Rattay (CHINA) 

Liu Zige of China celebrates with the gold medal after winning the women's 200 meters butterfly swimming final at the National Aquatics Center during the Beijing 2008 Olympic Games August 14, 2008. REUTERS/Jerry Lampen (CHINA) 

Liu Zige (L) of China is congratulated by Jessicah Schipper of Australia after the women's 200m butterfly swimming final during the Beijing 2008 Olympic Games at the National Aquatics Centre, August 14, 2008. Liu won the gold and set a new world record. REUTERS/David Gray (CHINA) 

Liu Zige (L) of China celebrates after winning the women's 200m butterfly swimming final next to bronze medal winner Jessicah Schipper of Australia during the Beijing 2008 Olympic Games at the National Aquatics Centre, August 14, 2008. The stadium is also known as the Water Cube. REUTERS/David Gray (CHINA) 

Liu Zige of China reacts after winning the women's 200 meters butterfly swimming final at the National Aquatics Center during the Beijing 2008 Olympic Games August 14, 2008. REUTERS/Wolfgang Rattay (CHINA) 

Liu Zige of China reacts after winning the women's 200 meters butterfly swimming final at the National Aquatics Center during the Beijing 2008 Olympic Games August 14, 2008. REUTERS/Jerry Lampen (CHINA) 

Liu Zige of China celebrates winning the women's 200 meters butterfly swimming final at the National Aquatics Center during the Beijing 2008 Olympic Games August 14, 2008. REUTERS/Wolfgang Rattay (CHINA) 

Liu Zige of China celebrates winning the women's 200 meters butterfly swimming final at the National Aquatics Center during the Beijing 2008 Olympic Games August 14, 2008. REUTERS/Wolfgang Rattay (CHINA) 

Liu Zige of China swims in the women's 200 meters butterfly final at the National Aquatics Center during the Beijing 2008 Olympic Games August 14, 2008. REUTERS/Wolfgang Rattay (CHINA) 

Liu Zige of China celebrates winning the women's 200 meters butterfly swimming final at the National Aquatics Center during the Beijing 2008 Olympic Games August 14, 2008. REUTERS/Jerry Lampen (CHINA) 

Liu Zige of China swims in her women's 200 meters butterfly heat at the National Aquatics Center during the Beijing Olympic Games August 12, 2008. REUTERS/Wolfgang Rattay (CHINA) 

Liu Zige of China competes in her women's 200m butterfly swimming heat at the National Aquatics Center during the 2008 Beijing Olympics, August 12, 2008. REUTERS/Jason Reed (CHINA)