He was pretty strong in the movie. He easily overpowered the winter soldier by grabbing that punch. He wasn't even trying or had any training.

I guess specifically cap overpowering him is my nitpick. I could understand why he would be able to though. Spiderman wasn't going his hardest and cap just sorta surprised him with a quick showing of strength. Spiderman doesn't weigh much so throwing him like that wouldn't be too crazy.