For the fight scenes in The Fighter, the producers hired a film crew that shoots real fights for HBO...and they shot all the fight scenes in three days instead of the industry standard 35 days. Here's Mark Wahlberg, the film's star and producer:
And what I kept telling everybody is that HBO does it in one take and they don't know what's going to happen and they never miss a thing. We have the luxury of showing them what we're going to do in the morning before we shoot it and doing it over and over and over again. So why do you need 20 days? For what? To jerk each other off? To touch up your makeup? To go in the trailer and take a nap?
We're not talking about putting the camera in there and saying, "OK, we're going to do a stunt punch here." No, we're going in there and beat the shit out of each other and we're going to make it real.