There is a very good reason that boxers have been running for conditioning since as long as it has been a sport, it is because running is about the best cardiovascular exercise out there especially if a boxer learns how to run in intervals and do sprints in their routine. Swimming is excellent exercise but unless a boxer has knee or shin problems I know that roadwork/running is superior for boxing-Good luck
For boxing? You know how they say running gives you the endurance and stamina? Well it does but swimming is one of the few things to replace that. So either one doesn't matter but I'd do both.
For boxing, nothing beats good old roadwork. You can probably cross-train at the pool once in a while but running should not be neglected.
Do maybe more swimming because it uses all muscles in your body helps a lot more.
running FOOL!!
Ok I'm 16 6'5 220 and very strong and do both evreyday and I was wondering is swimming better for you