First, you'll need to know your target heart rate. Target Heart Rate Range (simple) (220 - age) * 60-90% High intensity: ~75-90% Medium intensity: 60~75% (Not everyone switches over to high intensity at 75%. It's a higher percentage for those with better training.) For power and explosiveness, work at high intensity, though it's best not to do that more than every other training session, unless you do interval training. For faster recovery time, either is fine, though the medium intensity won't stress out your immune system like the high intensity will, hence why you shouldn't do high intensity every training session. After your warmup, go for 20-60 minutes at your target heart rate. You need to do this for at least 4 days a week to see results. It's better to do more days than more time, when forced to choose between the two, as long as you're getting the minimum of 20 minutes in each day. If you can't put in any more days of cardio training, go ahead and increase your time, but shoot for 4 days a week.
Before practice : Run stairs - (hit every step going up and down, don't skip) do interval of 30 seconds full speed 15 seconds walking. Then move up to 1 min on 20 seconds off. Before practice : Distance - run 1 mile 3-4 times for time. Try to beat time. I used to make the wrestlers run around the school halls which meant they had to go up a flight of stairs and down a flight to finish one lap. After practice : Sprints - long ways accross a gym. Some people call them suicides. Mix it up with bear walks, single legs, sprints crab walks etc. I used to coach and this was the program I used. If you want to do something in addition to this, work distance with aprint intervals and run hills (run up, walk down). Good luck
