Sara Slott Petersen of Denmark celebrates winning silver in the Women's 400m Hurdles Final on Day 13 of the Rio 2016 Olympic Games at the Olympic Stadium on August 18, 2016 in Rio de Janeiro, Brazil.

Kerron Clement of the United States leads Boniface Mucheru Tumuti of Kenya, Annsert Whyte of Jamaica and Thomas Barr of Ireland during the Men's 400m Hurdles Final on Day 13 of the Rio 2016 Olympic Games at the Olympic Stadium on August 18, 2016 in Rio de Janeiro, Brazil.

Boniface Mucheru Tumuti of Kenya reacts after placing second in the Men's 400m Hurdles Final on Day 13 of the Rio 2016 Olympic Games at the Olympic Stadium on August 18, 2016 in Rio de Janeiro, Brazil.

Eilidh Doyle of Great Britain reacts after the Women's 400m Hurdles Final on Day 13 of the Rio 2016 Olympic Games at the Olympic Stadium on August 18, 2016 in Rio de Janeiro, Brazil.

Yasmani Copello of Turkey reacts in the Men's 400m Hurdles Final on Day 13 of the Rio 2016 Olympic Games at the Olympic Stadium on August 18, 2016 in Rio de Janeiro, Brazil.

Dalilah Muhammad of the United States competes on her way to winning gold in the Women's 400m Hurdles Final on Day 13 of the Rio 2016 Olympic Games at the Olympic Stadium on August 18, 2016 in Rio de Janeiro, Brazil.

Kerron Clement of the United States celebrates after placing first in the Men's 400m Hurdles Final on Day 13 of the Rio 2016 Olympic Games at the Olympic Stadium on August 18, 2016 in Rio de Janeiro, Brazil.

Dalilah Muhammad of the United States celebrates winning gold in the Women's 400m Hurdles Final on Day 13 of the Rio 2016 Olympic Games at the Olympic Stadium on August 18, 2016 in Rio de Janeiro, Brazil.

Kerron Clement of the United States reacts after placing first in the Men's 400m Hurdles Final on Day 13 of the Rio 2016 Olympic Games at the Olympic Stadium on August 18, 2016 in Rio de Janeiro, Brazil.

Dalilah Muhammad of the United States, Sara Slott Petersen of Denmark, and Ashley Spencer of the United States compete in the Women's 400m Hurdles Final on Day 13 of the Rio 2016 Olympic Games at the Olympic Stadium on August 18, 2016 in Rio de Janeiro, Brazil.