Ralph Therrio was a pure track sprinter, who competed almost exclusively on the track. He was US Junior Champion in the sprint in 1971, and was California Junior sprint champion in 1970-72. Therrio raced the tandem sprint at the 1972 Olympics and the team pursuit in 1976. In 1975 Therrio won a gold medal in the team pursuit at the Pan American Games. He later became involved in human powered racing, setting world records for the 200 metre flying start in April 1977, with 9.060 (79.47 km/hr), bettering that in 1979 with 8.99, although that mark was not ratified. In April 1977 Therrio also posted a world record for the 500 metre flying start with 23.32 (77.19 km/hr).