Michael Phelps adds to his Olympic record total by winning his 19th Gold Medal, in the Men's 4x100m Freestyle Relay, at the 2016 Rio Olympics. Aug. 7, 2016, Rio de Janeiro.

Allyson Felix, right, and English Gardner of the United States after dropping the baton in a women's 4x100-meter relay heat during the athletics competitions of the 2016 Summer Olympics at the ...

Meet the team: Simone Biles Simone Biles competes on the balance beam during Day 2 of the 2016 U.S. Women's Gymnastics Olympic Trials at SAP Center, July 10, 2016 in San Jose, California.