Complex sentence: He won the Mr. Universe title at age 20 and went on to win the Mr. Olympia contest seven times, remaining a prominent presence in bodybuilding and writing many books and articles on the sport.
Split into simpler sentences: He won the Mr. Universe title at age 20 and went on to win the Mr. Olympia contest seven times. Schwarzenegger has remained a prominent presence in bodybuilding and has written many books and articles on the sport.