Ryan,
I've trained both Amateurs and Pro's and let me tell you, you ain't training for a marathon, you're conditioning yourself for a three round fight if you're an amateur or a twelve (max) if you're a Pro. You should run no more than 4 miles PERIOD. Yeah it would help your cardio if you ran 5,10 or 15 miles but you're not gaining anything in BOXING.
There was once a study done back in the seventies when Ali was king and if you were to move around the ring (20 by 20) you would only run an average of 2.2 miles in a 15 round fight. With that said why would you chose to run any more? Fighters are not moving around the ring the whole time that they are in the ring, they need to stop o throw punches, they need to stop when being held.
Run a nice 8 to 9 minute a mile pace for 3 to 4 miles, 5 days a week and you will be fine.
i ran on days i didn't train usually 3 days a week not to far about 3 miles but i would ran quickly taking about 20 minutes
I used to kick box. I ran every Monday,Wednesday, Friday, Saturday Sunday. I ran a single mile in about 6 minutes. All boxing is cardio, endurance, stamina, and technique. People believe power before speed!! But first get technique down then speed then power will come later on in training!! The days you don't run do body Hardening, sit ups and push ups to stay in shape. Or jog at a talking pace with a flak jacket on ( its what military people wear) to build leg strength bc in later rounds your legs will be getting weak from dancing around the ring. You can also shadow box your self in front of a mirror too, to help your technique and speed down. Another idea is wind sprints for bursts of speed, bc it doesn't matter about knock out or tkos in amateur boxing matches its all about the points baby!!! The faster you can get inside on someone to unload some fast combos te more points you have!!
Have fun keep training and like my coach always said "never ever quit"
For all the amateur boxers how many days a week do you run, how long also what is your fastest mile. put other fitness things you do like sprints etc.