I am not sure how it's humanly possible to do this, but 36-year-old James Harrison makes it look incredibly easy. Here's video of Harrison shoulder-pressing 135 pounds with one hand.
Harrison is near the end of his career, but there's no way that you can ever question is strength again after seeing this video. This is just absolute brute strength.
Oh, and if you forgot, Harrison was signed off of his couch in September last season and ended up being one of the Steelers' best defenders.
