This is the trailer to Australian film The Coolangatta Gold, directed by Igor Auzins and released on 22 November 1984, which led to the establishment of the Ironman race of the same name.
The film is about two sons (played by Colin Friels and Joss McWilliam) who compete for the love of their authoritarian father (Nick Tate). He is determined that one of his sons should win the Coolangatta Gold contest, which involves swimming, running and surfing.
To shoot the movie the producers decided to run the race as an actual competition. Many well-known Ironmen at the time competed but it was won by relative unknown, Guy Leech. Leech also won it the following year. The event wasn't held again until 1991 with the inaugural women's competition commencing in 2005.
The film was a box-office disappointment but the Coolangatta Gold event has become a fixture on the Ironman surf lifesaving calendar.