Corenswet's physical trainer breaks down the routine that helped the formerly svelte actor put on 40 pounds of muscle—and how ...

Furthermore, while the muscle suit that Reeves wore underneath the suit definitely sold the idea that Superman was well-built ...

"Adventures of Superman" producer Robert Maxwell didn't think Reeves had the physique to fill out the suit like Alyn, so he wore a rubber muscle prosthetic under his shirt to make him look bigger ...