Much of the time when we think actor in role of boxer the majority of it is in ring and tends to be the lead in to their story, build to triumph and early career etc. One of the best I've ever seen as a kid was Requiem For a Heavyweight. It focused on the exact opposite end and it seems many of the boxing themed movies around the 30s thru 60s could be pretty dark. Mickey Rooney, Gleason and Anthony Quinn were spot on in this one. Opening line up shot is great too..looks like a run of current and past fighters of the era but can make out Willie Pep and Barney Ross and of course young Ali. Love the way it's shot.