ofcourse it couldnt hurt to do some extra training aslong as you are not over training. put your boxing training ahead of your running, you are training to be a boxer not a runner..
Sport-specific things comes first, training, bag perform, shadowboxing, exercises, etc. Besides that I go operating a few periods per 7 days, I pattern between 20 and 40 km a day, and as soon as the elements allows it I'll be diving and kayaking a lot.
I think many folks are missing the point. It matters less WHAT you do or what distance, but HOW INTENSELY you do it. For example, I only run about 3 miles or do 20 minutes of intense exercise about twice a week (plus sparring/heavy bag) with and my conditioning is one of my stronger assets. Whatever gets your heart rate and breathing really high and improves your capacity to perform under these conditions is crucial.
In my area novices fight 3 x 2 min rounds. You are ready when you can: Do well in HEAVY sparring against better/more experienced opponents with 3 x 3 minute rounds or maybe 3 x 2 minute rounds with 30 sec rest. That will be the true measure. Forgot about all the "non-boxing fitness ****". Do this, you will be ready. The key is gauging your progress under more stress (ie longer rounds/shorter rest) against GOOD opponents.
while you're a novice, boxing is definitely key to being a better and fitter boxer. if you have extra energy outside of the gym, a few 3-5k runs will help improve your cardio and alternate with a few sprint sessions to improve your threshold. but heavybag and sparring sessions will best prepare you for the first 10 or so fights.
Running every night is not necessary, however, it can help to manage your calories/weight. So if you enjoy it, it certainly can't hurt. Me personally, I don't care much for running. So i'll run maybe once or twice a week. 3 miles tops. Intervals of fast then slow, roughly every 30 seconds (I just count street lights) and i'll do it in about 21.5 minutes. I also do some plyo/agility ladder exercises - again, no more than 5 rounds. Conditioning really doesn't need to exceed anything more than 20 minutes, as long as you have some intensity and get your breathing and heart rate pumping fast. It's less important what you do, or how far you go - and more important that you are working hard for something that might match the intensity & duration of a few rounds.
My strength n conditioning coach told me to run a good fast for 20~25 min to develop a good cardio base 3~4 times a week. And the days when we don't run would be mostly sprinting and interval exercises. And we would do a good hard sparring going at full pace once a week to give it a feel of a fight. And do regular technical sparring when we don't do hard sparring.
