Phelps was the first Nebraskan to clear the 7-foot barrier in the high jump. He won three straight gold medals at the state meet and, his senior season, broke the state record five times. He was a three-year, three-sport letterman for the Tigers, competing in football and basketball, named all-conference in both. He was the 1975 Omaha World-Herald and Lincoln Journal Star Athlete of the Year. At the University of Nebraska, he was a three-year letterman in track and the 1978 Big Eight indoor and outdoor champion in the high jump.