Keith Laumer's The Body Builders
Yeah this is a rip-off. When I read about this movie, I thought, "Great! They are making a movie from a short by one of my favourite Golden age sci-fi writers!"
But, no. Poor Keith Laumer even doesn't get mentioned in the credits. Anyone remember the outrage when several Philip K. Dick's stories got filmed, suitably "altered" to fit the modern times, and thus were claimed to be "original"? Here is another!
By the way, one of the reasons I loved "The Body Builders" (1966! as old as I am!) is one of the "surrogates" types you could buy was called the "Geesink". I guess anyone younger than me has to look *him* up on wikipedia :-)