actually, all the major AAU bodybuilding contests were held as part of (olympic style) weightlifting events. In the 1970s, a few were held with powerlifting championships.
and well into the 1970s, athletic ability in another sport was counted as part of your score, along with appearance, grooming, and interview ability. therefore, the most muscular guy rarely won. but the IFBB decided to be different and said they'd judge their contests soley on muscularity.