i'm 15 and every thursday i spar with someone who is probably around 42-48 he's in incredible shape, i spar 3 lots of 2 minute rounds, and i'm puffing and panting, and he still has about 9-10 more rounds left. He spars properly and he's landed some sweet shots over the past 6 or so weeks. You have to remember older boxers have much more experience, and in this case, are much more ring fit!
There are some guys in my gym that are in late 40s and I've sparred with them occasionally and their boxing skills are fantastic, but I do feel bad for hitting the old man because I'm 17. But we would limit our powers depending on their skill level, weight, and such.
"Ring fit". I guess that's a good way to describe someone who shouldn't have better cardio than you, but can somehow beat your ass for 5 or 6 rounds. My kickboxing coach was 47. He seemed to go on forever, was fast and was so hard to hit. Rib injuries were one of the main reasons I stopped kickboxing to focus on boxing.
It's because these old guys have to be efficient with their movement. Boxers don't have to be all that fit really, just look at James Toney.
Yeah, that's exactly why he's one of my favourite boxers to watch. His efficiency and minimalistic movement is like watching a matador dance around a bull.
I was in Colorado a little while back, some big old guy, over 60, but HUGE, was sparring EVERYBODY. Ugly, but effective south paw style. This dude was a tank, and he fought with all the dirty tricks from the old days. It was a riot watching him wear out and manhandle all the cocky young fighters.