Alberto Juantorena is a Cuban former runner. He is the only athlete to win both the 400 and 800 m Olympic titles, which he achieved in 1976. He was ranked as the world's best runner in the 400 m in 1974 and 1976–1978, and in the 800 m in 1976–77, and was chosen as the Track & Field News Athlete of the Year in 1976 and 1977. Alberto Juantorena (Cuba) set the men's 400 m world record of 44.26 in Montreal, Canada on July 29, 1976. It stood 10.8 years, until Butch Reynolds's 44.10 on May 3, 1987. Wiki link