NBCUniversal/The Tonight Show

Watch The Rock And Jimmy Fallon As The Pumped-Up Fungo Brothers

If you wanna get stacked, you gotta jack it!

You probably already know Dwayne "The Rock" Johnson is his usual ripped self in "Hercules." But did you realize that before he hit the big screen he was also one half of the fitness duo The Fungo Brothers?

"About a year ago I found this old VHS tape that had a bunch of clips of this fitness duo called The Fungo Brothers," Johnson told "Tonight Show" host Jimmy Fallon on Tuesday night of his top-secret method for getting in shape for his movies.

"They were really ahead of their time," Fallon said of the floppy-haired, tank top-loving brothers. "All the fitness trends over the years: the Thighmaster, the Shake Weight... They were never quite successful but they were always so close to the next big thing." Of course Fallon found the archival tape of the pair doing their retro thing, and it was awesome. All we can say is this: "You want glutes harder than plaster?... You gotta hustle for the muscle!"

Oh wait, there's more. And this time it's a clip from the 1950s when the Fungos tried to invent their own dance craze, "The Squat Thrust." It did not catch on.