How long can you hit a heavy bag?

I was having a discussion with my work friend, who was an Army Ranger. We get into debates all the time. This time he said he used to hit a heavy bag as hard and fast as he could for 5 minutes. I do 5 minute rounds, and then 30 seconds sprints on the end like.. "punch it out".. and five minutes of "punching it out" sounds pretty extreme. He said they'd keep a consistant pace. Do you believe it.. and can you do it?

You can keep a constant punching pace for 5 minutes. You can even be able to do this for rounds if you're in really good shape. That is possible and I do it all the time but punching it out for 5 minutes straight? I call BULLSHIT!!!

I've seen some guys in really good shape who could punch all day long but couldn't do that. If he can do that, he needs to be a fighter cause there wouldn't be anyone who could keep up with him in the ring.

Ferox is correct.

LoL.. thing is, this guy says he used to train with Ranger Stott. Haha.

He made the point that they were still effective punches with proper form.. [although by looking at his, I call bullshit.] I'm already calling bullshit on this, but I wanted to see if it was do-able.

Only once, then its KTFO too

Full power, consistent, straight punches for 5 minutes? Bullshit.

Alright. Thanks. I'm not like the pro fighters, KTFO heavy bags.. But ask Mike Swick, I ripped up the focus mit when he was holding for me. It's even on his myspace. Heavybags will be the next step.

No.. he said 5 minutes, the same pace the whole time..with the exact speed,power, and form as the first punch.. Sorry if I didnt make it clear.

I've gone 30 minutes(..or more) on a bunch of occaisons, but DEFINITELY not an all-out sprint for the entire time(... would have probably lasted 60 sec that way).

I used to do it as an aerobic work-out (and because I enjoyed it). It was definitely non-stop, but I would jab, move, throw combinations, jab, move, all-out flurry, blah, blah, blah... Other words I would very the intensity. Maybe that's what he meant?