IOWA CITY, IA -- ESPN Classic will air a one-hour long episode on the life of former Iowa wrestling coach Dan Gable as part of its Sports Century program. The episode will air Thursday, April 26, 2001 at 7 p.m. (CT).     Gable, Iowa's all-time winningest wrestling coach, compiled a career record of 355-21-5 in 21 seasons at Iowa (1977-97). Under him, the Hawkeyes won 15 NCAA team titles and 21 Big Ten team titles.     Gable was a 1972 Olympic gold medalist and 1971 World Champion. He has served as head coach of three U.S. Olympic teams (1980, 1984, 2000).    Gable currently serves as Assistant to the Athletic Director at the University of Iowa