Originally Posted by Brian Braddock
Y'know, I've always wondered this ever since the Six Million Dollar man - how would a bionic arm give a person the ability to, say, stop a moving car or punch through a steel door when it's basically still just attached to regular ol' human tissue. At best, wouldn't the arm just kind of rip from the tissue and go flying?
Well, for realistic(?) cybernetics, the solution is to not just have a cybernetic arm. Rather, you reinforce or replace much of the skeleton, too.
As for the movie, bear in mind that Bucky was almost certainly subject to some kind of quasi-supersoldier serum experiment. Wouldn't be shocking if he's physically enhanced even beyond the cyborg arm. . . and I would totally buy that bones and muscles even half as strong as movie Cap's would be fine with any reasonable cyborg arm strength.