It’s likely the most important film ever created about bodybuilding. The movie serves as an excellent example for documentary filmmakers, although its style leans more toward a docudrama than a standard documentary. The blurring of lines between what's real and fabricated was done in a smart way, contributing to the later surge in popularity of both bodybuilding and fitness. It also gave audiences their first look at Arnold Schwarzenegger, who would subsequently become highly successful in numerous areas, frequently as an innovator, even when others doubted him. When he was at his highest level in competitive bodybuilding, Schwarzenegger comes across as intelligent and determined, prepared to give up anything—truly everything—in pursuit of victory. Lou Ferrigno, who later became famous for playing the Hulk on television, is shown as his competitor; a quiet and sensitive person with an overbearing father. These contrasting personalities are used to illustrate the 1970s American bodybuilding world and make it understandable to viewers.

Source on TMDB