Guide Wesley Williams (left) lines up blind long jumper and sprinter Lex Gillette on the track before making a long jump during practice at the U.S. Olympic Training Center in San Diego. Gillette started losing his sight when he was 8 years old.
Bill Wechter for NPR
Anita Alvarez and Mariya Koroleva compete in the women's duets synchronized swimming technical routine preliminary on Monday in Rio de Janeiro. Koroleva has suffered several concussions over the years.
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