Nanjing 2014 - Gold metalists Hannah Moore (R) of United States of America and Ambra Esposito of Italy and bronze metalist Africa Zamorano Sanz of Spain pose on the podium after women's 200m backstroke final event at the Nanjing 2014 Youth Olympic Games in Nanjing, east China's Jiangsu Province, Aug. 19, 2014. Petrova won the silver medal.

(R-L) Madeline Dirado of the United States and Katinka Hosszu of Hungary compete in the Women's 200m Backstroke Final on Day 7 of the Rio 2016 Olympic Games at the Olympic Aquatics Stadium on August 12, 2016 in Rio de Janeiro, Brazil.

Ryan Murphy of the United States celebrates after winning gold in the Men's 200m Backstroke Final on Day 6 of the Rio 2016 Olympic Games at the Olympic Aquatics Stadium on August 11, 2016 in Rio de Janeiro, Brazil.

Mitch Larkin of Australia competes in the Men's 200m Backstroke Final on Day 6 of the Rio 2016 Olympic Games at the Olympic Aquatics Stadium on August 11, 2016 in Rio de Janeiro, Brazil.

Mitch Larkin of Australia competes in the Men's 200m Backstroke Final on Day 6 of the Rio 2016 Olympic Games at the Olympic Aquatics Stadium on August 11, 2016 in Rio de Janeiro, Brazil.

Evgeny Rylov of Russian Federation competes in the Men's 200m Backstroke Final on Day 6 of the Rio 2016 Olympic Games at the Olympic Aquatics Stadium on August 11, 2016 in Rio de Janeiro, Brazil.

Evgeny Rylov of Russian Federation competes in the Men's 200m Backstroke Final on Day 6 of the Rio 2016 Olympic Games at the Olympic Aquatics Stadium on August 11, 2016 in Rio de Janeiro, Brazil.

Ryan Murphy of the United States competes in the Men's 200m Backstroke Final on Day 6 of the Rio 2016 Olympic Games at the Olympic Aquatics Stadium on August 11, 2016 in Rio de Janeiro, Brazil.

Nanjing 2014 - Gold medalist Li Guangyuan of China,silver medalist Evgeny Rylov of Russian Federation and Bronze medalist Luke Greenbank of Great Britain on the podium during the awarding ceremony after the Men's 200m Backstroke match at Nanjing 2014 Youth Olympic Games in Nanjing, capital of Jiangsu Province, on Aug. 22, 2014.

(L-R) Silver medalist Mitch Larkin of Australia, gold medalist Ryan Murphy of the United States and bronze medalist Evgeny Rylov of Russian Federation celebrate on the podium after the Men's 200m Backstroke Final on Day 6 of the Rio 2016 Olympic Games at the Olympic Aquatics Stadium on August 11, 2016 in Rio de Janeiro, Brazil.