Complex sentence: He was also a gold medalist at both the 1975 and 1979 Pan-American Games and a member of the 1980 U.S. Olympic team that boycotted the XXII Olympiad in Moscow.
Split into simpler sentences: He was also a gold medalist at both the 1975 and 1979 Pan-American Games. In 1980, he was a member of the U.S. Olympic team that boycotted the Olympic Games in Moscow.