How to get in Boxing Shape
Boxing Roadwork is it out dated? Yes and No. The belief that running 5 miles will get you in shape to Box is a little misleading. Running 5 miles doesn't effectively mimick your heart rate during a fight. Jogging long distance keeps your heart at slow methodical pace. A Boxing match consists of times where your heart soars,drops back down, then soars again.
The only real way to get in Boxing condition is actual live sparring. The next best alternative is interval training. Sprint and agility drills will raise your heart rate as if you were rattling off a combinations in the ring. Interval training on the heavy bag is also effective. For example work on speed for 20 sec, then power the next 20, then power and speed, lastly throw in some squat and repeat the cycle. You want to do drills where you're breathing heavy, and reacting fast. This type of training more closely mimicks what your heart rate will go through during live competition.
Roadwork is still necessary. It is very effective in taking off weight and building up a baseline conditioning level so that you can perform basic boxing exercises to improve your game. Also there is a psychological advantage to running 3-5 miles. A fighter mentally feels he did everything to prepare. The fighter can almost meditate while running and think about the fight at hand.
Bottom line is get in absolute professional boxing shape you must spar, do your roadwork, and perform speed/interval training. If you're not a competitive boxer working the mitts, roadwork, bag training and intervals are enough.
Boxing Tip: Do your roadwork at night or after your actual boxing training. Save your legs for the gym.