Amateur and professional bodybuilders prepare for the 1975 Mr. Olympia and Mr. Universe contests as five-time champion Arnold Schwarzenegger defends his Mr. Olympia title against Serge Nubret and the shy young Lou Ferrigno.
| Actor | Role |
|---|---|
 Arnold SchwarzeneggerSelf | Self |
 Lou FerrignoSelf | Self |
| MMike KatzSelf | Self |
| SSerge NubretSelf | Self |
 Franco ColumbuSelf | Self |
| EEd CorneySelf | Self |
| KKen WallerSelf | Self |
| RRobbie RobinsonSelf | Self |
| MMarianne ClaireSelf | Self |
 Roger CallardSelf | Self |
 Bud CortSelf | Self |
 Jimmy WilliamsSelf | Self |
| JJoe WeiderSelf | Self |
| PPaul GrantSelf | Self |
| JJohn IsaacsSelf | Self |
| MMatty FerrignoSelf | Self |
| VVictoria FerrignoSelf | Self |
 Roger WalkerSelf | Self |
| CCharles GainesNarrator | Narrator |