Alexander Ludwig -- Director Punched the Hell Outta Me ... And I Loved It (Video)

Alexander Ludwig was a human punching bag on the set of his new movie, "Final Girl" -- and director Tyler Shields was the one delivering the blows to his chiseled abs and face.

We got this clip of Shields pumping up Ludwig for an intense scene by landing several combination punches to the body. The video's pretty awesome -- either Tyler's a total lightweight or Alexander's a total badass ... 'cause he doesn't flinch.

We're gonna go with option #2.