Jojo's Bizarre Adventure is a monument to the time in which it was made, littered as it is with musical references and the culture of the day. But Jojo drew inspiration from other areas besides music, and it turns out one of them was the action movie stars of the 1980s.
The series Jojo's Bizarre Adventure was created by Hirohiko Araki in 1986. Araki was (and still is) a big fan of Western culture, and worked many of his interests into the story, despite it being set a hundred years prior, in the 1880s. When designing the hero of his story, he decided that Jonathan Joestar should be a "symbol of justice" who would find his way in JoJo's Bizarre Adventure's world as a force opposing Dio (who Araki says was the character that he really wanted to draw). In fact, Jonathan's character design was built around the idea that he would one day have to fight Dio.
Jonathan Joestar's Physique Was Inspired by Schwarzenegger
In a special interview found in the first "Jojonium" edition of the manga, Araki explains that Jonathan was made to be muscular and strong with his inevitable battle with Dio later in JoJo's Bizarre Adventure in mind. Jonathan would have to be able to withstand an onslaught of powerful attacks, like a Western action movie hero. The biggest action stars at the time were Sylvester Stallone and Arnold Schwarzenegger, both of whom Araki mentions as inspiring Jonathan's muscular physique. It was important for Jonathan to look like he could handle himself in a fight, so who better to model him after than America's most famous bodybuilder?
By 1986, Schwarzenegger was still pretty new to the Hollywood scene; Araki most likely saw him in 1984's The Terminator, where Arnold plays the villainous T-800 and barely speaks in the film, but might also have known him from Conan the Barbarian, his first big break from 1982. Araki says he wanted Jonathan to have a feeling of "unstoppableness," stating that no amount of bullets could stop a Scwarzenegger character (which definitely suggests Terminator as inspiration). The idea for Dio and Jonathan's confrontation, then, kind of seems like the old "unstoppable force" versus "immovable object," adding an epic feel to their battle by making both parties seem absolutely unbeatable. Araki also decided to add an Eastern bent to the character by taking some inspiration from martial arts manga, which were quite popular at the time as well. This mostly took the form of Hamon techniques, which he hoped would provide an air of the supernatural to supplement Jonathan's physical strength.
Given his limited film experience at the time, Arnold Schwarzenegger was certainly an interesting choice for inspiration, but anyone who looks at the muscular characters of early Jojo's Bizarre Adventure ought to be able to recognize the influence the bodybuilding actor had.
Source: Jojonium