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American swimmer Mark Spitz won 31 AAU titles in his career. Spitz competed in the AAU Championships for 12 years, from 1964 to 1976. He won a total of 45 medals at the AAU Championships, including 31 gold medals, 10 silver medals, and 4 bronze medals. Spitz was the most successful swimmer in AAU history, and he is considered to be one of the greatest swimmers of all time.