Swimming – 17th FINA World Aquatics Championships – Women's 100m Butterfly semifinal – Budapest, Hungary – July 23, 2017 – Sarah Sjostrom of Sweden competes. REUTERS/Stefan Wermuth 

Swimming – 17th FINA World Aquatics Championships – Women's 100m Butterfly semifinal – Budapest, Hungary – July 23, 2017 – Sarah Sjostrom of Sweden competes. REUTERS/Bernadett Szabo 

Swimming – 17th FINA World Aquatics Championships – Women's 100m Butterfly semifinal – Budapest, Hungary – July 23, 2017 – Sarah Sjostrom of Sweden competes. REUTERS/Stefan Wermuth 

Swimming – 17th FINA World Aquatics Championships – Women's 100m Butterfly semifinal – Budapest, Hungary – July 23, 2017 – Sarah Sjostrom of Sweden competes. REUTERS/Laszlo Balogh 

Swimming – 17th FINA World Aquatics Championships – Women's 100m Butterfly semifinal – Budapest, Hungary – July 23, 2017 – Sarah Sjostrom of Sweden competes. REUTERS/Stefan Wermuth 

Swimming – 17th FINA World Aquatics Championships – Women's 100m Butterfly semifinal – Budapest, Hungary – July 23, 2017 – Sarah Sjostrom of Sweden competes. REUTERS/Laszlo Balogh 

Swimming – 17th FINA World Aquatics Championships – Women's 100m Butterfly Preliminary – Budapest, Hungary – July 23, 2017 – Sarah Sjostrom of Sweden prepares for start. REUTERS/Michael Dalder 

Swimming – 17th FINA World Aquatics Championships – Women's 100m Butterfly Preliminary – Budapest, Hungary – July 23, 2017 – Sarah Sjostrom of Sweden competes. REUTERS/Bernadett Szabo 

Swimming – 17th FINA World Aquatics Championships – Women's 100m Butterfly Preliminary – Budapest, Hungary – July 23, 2017 – Sarah Sjostrom of Sweden competes. REUTERS/Michael Dalder 

Swimming – 17th FINA World Aquatics Championships – Women's 100m Butterfly preliminary – Budapest, Hungary – July 23, 2017 – Sarah Sjostrom of Sweden competes. REUTERS/Stefan Wermuth 

Swimming – 17th FINA World Aquatics Championships – Women's 100m Butterfly Preliminary – Budapest, Hungary – July 23, 2017 – Sarah Sjostrom of Sweden competes. REUTERS/Michael Dalder 

Swimming – 17th FINA World Aquatics Championships – Women's 100m Butterfly Preliminary – Budapest, Hungary – July 23, 2017 – Sarah Sjostrom of Sweden prepares for start. REUTERS/Michael Dalder 

Swimming – 17th FINA World Aquatics Championships – Women's 100m Butterfly preliminary – Budapest, Hungary – July 23, 2017 – Sarah Sjostrom of Sweden competes. REUTERS/Stefan Wermuth 

Sweden's second placed Louise Hansson, Michelle Coleman, Sarah Sjostrom and Jennie Johansson pose with medals after the women's 4x100m medley relay final at the Aquatics World Championships in Kazan, Russia, August 9, 2015. REUTERS/Stefan Wermuth

Sweden's second placed Louise Hansson, Michelle Coleman, Sarah Sjostrom and Jennie Johansson pose with medals after the women's 4x100m medley relay final at the Aquatics World Championships in Kazan, Russia, August 9, 2015. REUTERS/Hannibal Hanschke 

Sweden's second placed Michelle Coleman, Louise Hansson, Sarah Sjostrom and Jennie Johansson wave after the women's 4x100m medley relay final at the Aquatics World Championships in Kazan, Russia, August 9, 2015. REUTERS/Michael Dalder

Third placed Sarah Sjostrom of Sweden poses with her medal after the women's 50m freestyle final at the Aquatics World Championships in Kazan, Russia, August 9, 2015. REUTERS/Stefan Wermuth

Silver medallist Ranomi Kromowidjojo of the Netherlands, gold medallist Bronte Campbell of Australia and bronze medallist Sarah Sjostrom of Sweden (L-R) celebrate after winning the women's 50m freestyle final at the Aquatics World Championships in Kazan, Russia, August 9, 2015. REUTERS/Michael Dalder

Sweden's Sarah Sjostrom celebrates after receiving her gold medal for the women's 50m butterfly final at the Aquatics World Championships in Kazan, Russia, August 8, 2015. REUTERS/Michael Dalder (RUSSIA - Tags: SPORT SWIMMING)

Silver medallist Jeanette Ottesen of Denmark, gold medallist Sweden's Sarah Sjostrom and bronze medallist China's Lu Ying (L-R) pose with their medlas after winning the women's 50m butterfly final at the Aquatics World Championships in Kazan, Russia, August 8, 2015. REUTERS/Michael Dalder

Sweden's Sarah Sjostrom poses with her gold medal after winning the women's 50m butterfly final at the Aquatics World Championships in Kazan, Russia, August 8, 2015. REUTERS/Stefan Wermuth

Sweden's Sarah Sjostrom celebrates after winning the women's 50m butterfly final at the Aquatics World Championships in Kazan, Russia, August 8, 2015. REUTERS/Hannibal Hanschke 

Sweden's Sarah Sjostrom celebrates after winning the women's 50m butterfly final at the Aquatics World Championships in Kazan, Russia, August 8, 2015. REUTERS/Michael Dalder

Sweden's Sarah Sjostrom reacts after winning the women's 50m butterfly final at the Aquatics World Championships in Kazan, Russia, August 8, 2015. REUTERS/Michael Dalder

Sweden's Sarah Sjostrom reacts after winning the women's 50m butterfly final at the Aquatics World Championships in Kazan, Russia, August 8, 2015. REUTERS/Michael Dalder

Sweden's Sarah Sjostrom celebrates her victory in the women's 50m butterfly final at the Aquatics World Championships in Kazan, Russia, August 8, 2015. REUTERS/Michael Dalder

Sweden's Sarah Sjostrom celebrates her victory in the women's 50m butterfly final at the Aquatics World Championships in Kazan, Russia, August 8, 2015. REUTERS/Stefan Wermuth (RUSSIA - Tags: SPORT SWIMMING)

Sweden's Sarah Sjostrom celebrates her victory in the women's 50m butterfly final at the Aquatics World Championships in Kazan, Russia, August 8, 2015. REUTERS/Stefan Wermuth

Arianna Vanderpool-Wallace of Bahamas, Sarah Sjostrom of Sweden and Simone Manuel of the U.S. (from bottom) start in the women's 50m freestyle heats at the Aquatics World Championships in Kazan, Russia, August 8, 2015. REUTERS/Stefan Wermuth

Sarah Sjostrom of Sweden reacts after the women's 50m freestyle heats at the Aquatics World Championships in Kazan, Russia, August 8, 2015. REUTERS/Michael Dalder

Sweden's Sarah Sjostrom spurts water after the women's 50m butterfly semi-final at the Aquatics World Championships in Kazan, Russia, August 7, 2015. REUTERS/Hannibal Hanschke

Sweden's Sarah Sjostrom prepares for the women's 50m butterfly semi-final at the Aquatics World Championships in Kazan, Russia, August 7, 2015. REUTERS/Stefan Wermuth

Sarah Sjostrom of Sweden reacts after the women's 50m butterfly semi-final at the Aquatics World Championships in Kazan, Russia August 7, 2015. REUTERS/Michael Dalder

Sarah Sjostrom of Sweden smiles after the women's 50m butterfly semi-final at the Aquatics World Championships in Kazan, Russia, August 7, 2015. REUTERS/Michael Dalder

Sarah Sjostrom of Sweden spurts water after the women's 50m butterfly semi-final at the Aquatics World Championships in Kazan, Russia, August 7, 2015. REUTERS/Stefan Wermuth

Sarah Sjostrom of Sweden swims in the women's 50m butterfly semi-final at the Aquatics World Championships in Kazan, Russia August 7, 2015. REUTERS/Michael Dalder TPX IMAGES OF THE DAY

Sarah Sjostrom of Sweden swims in the women's 50m butterfly semi-final at the Aquatics World Championships in Kazan, Russia August 7, 2015. REUTERS/Michael Dalder

Sarah Sjostrom of Sweden, Bronte Campbell of Australia and her compatriot Cate Campbell (L-R) display their medals after the women's 100m freestyle final at the Aquatics World Championships in Kazan, Russia August 7, 2015. REUTERS/Michael Dalder

Sarah Sjostrom of Sweden displays her silver medal after the women's 100m freestyle final at the Aquatics World Championships in Kazan, Russia August 7, 2015. REUTERS/Stefan Wermuth

Australia's first placed Bronte Campbell (L-R) celebrates with her third placed sister Cate and second placed Sarah Sjostrom of Sweden after the women's 100m freestyle final at the Aquatics World Championships in Kazan, Russia, August 7, 2015. REUTERS/Stefan Wermuth 

Second placed Sarah Sjostrom (L-R) of Sweden and Australia's first placed Bronte Campbell and her third placed sister Cate celebrate after the women's 100m freestyle final at the Aquatics World Championships in Kazan, Russia, August 7, 2015. REUTERS/Stefan Wermuth 

Sarah Sjostrom of Sweden (R) and Cate Campbell of Australia (C) swim in the women's 100 freestyle final at the Aquatics World Championships in Kazan, Russia, August 7, 2015. REUTERS/Michael Dalder

Sarah Sjostrom of Sweden swims in the women's 100 freestyle final at the Aquatics World Championships in Kazan, Russia, August 7, 2015. REUTERS/Michael Dalder

Second placed Sarah Sjostrom (R) of Sweden watches Australia's first placed Bronte Campbell (L) celebrating with her third placed sister Cate at the women's 100m freestyle final at the Aquatics World Championships in Kazan, Russia, August 7, 2015. REUTERS/Michael Dalder 

Sarah Sjostrom of Sweden (R) and Cate Campbell of Australia (C) swim in the women's 100 freestyle final at the Aquatics World Championships in Kazan, Russia, August 7, 2015. REUTERS/Michael Dalder

Sarah Sjostrom of Sweden pours water on herself before the women's 100m freestyle final at the Aquatics World Championships in Kazan, Russia, August 7, 2015. REUTERS/Michael Dalder TPX IMAGES OF THE DAY 

Sarah Sjostrom of Sweden in women's 50m butterfly heat at the Aquatics World Championships in Kazan, Russia, August 7, 2015. REUTERS/Stefan Wermuth 

Sarah Sjostrom of Sweden competes in the women's 100m freestyle heat at the Aquatics World Championships in Kazan, Russia, August 6, 2015. REUTERS/Michael Dalder

Sweden's Sarah Sjostrom prepares for the women's 100m freestyle semi-final at the Aquatics World Championships in Kazan, Russia, August 6, 2015. REUTERS/Hannibal Hanschke

Sarah Sjostrom of Sweden swims in the women's 100m freestyle semi-final at the Aquatics World Championships in Kazan, Russia August 6, 2015. REUTERS/Michael Dalder 

Sarah Sjostrom of Sweden swims in the women's 100m freestyle semi-final at the Aquatics World Championships in Kazan, Russia August 6, 2015. REUTERS/Michael Dalder 

Sarah Sjostrom of Sweden rests after the women's 100m freestyle heat at the Aquatics World Championships in Kazan, Russia, August 6, 2015. REUTERS/Stefan Wermuth

Sarah Sjostrom of Sweden rests after the women's 100m freestyle heat at the Aquatics World Championships in Kazan, Russia, August 6, 2015. REUTERS/Stefan Wermuth

Sarah Sjostrom (front) of Sweden and Simone Manuel of the U.S. start in the women's 100m freestyle heat at the Aquatics World Championships in Kazan, Russia, August 6, 2015. REUTERS/Stefan Wermuth

Sarah Sjostrom (C) of Sweden and Simone Manuel of the U.S. start in the women's 100m freestyle heat at the Aquatics World Championships in Kazan, Russia, August 6, 2015. REUTERS/Stefan Wermuth

Sarah Sjostrom of Sweden competes in the women's 100m freestyle heat at the Aquatics World Championships in Kazan, Russia, August 6, 2015. REUTERS/Michael Dalder

Sarah Sjostrom of Sweden competes in the women's 100m freestyle heat at the Aquatics World Championships in Kazan, Russia, August 6, 2015. REUTERS/Michael Dalder

Sarah Sjostrom of Sweden competes in the women's 100m freestyle heat at the Aquatics World Championships in Kazan, Russia, August 6, 2015. REUTERS/Michael Dalder

Gold medallist Sweden's Sarah Sjostrom celebrates after the women's 100m butterfly final during the Aquatics World Championships in Kazan, Russia August 3, 2015. REUTERS/Stefan Wermuth

Gold medallist Sweden's Sarah Sjostrom and Silver medallist Denmark's Jeanette Ottesen (R) celebrate after the women's 100m butterfly final during the Aquatics World Championships in Kazan, Russia August 3, 2015. REUTERS/Stefan Wermuth