Originally Posted by c172g

I posted this in a different thread, but get a speed bag & double-ended bag (Everlast). You can buy both for under a hundred bucks. Once you get the feel of the speed bag (don't forget bag gloves or your knuckles will be wrecked), do three or four sets of 4-5 minutes (turn on the mp3 player for 1 good song). Shoulders, triceps, biceps, back, etc. Best & most fun exercises around. The double ended bag is better for your back if you use a boxing stance where you are 90 degrees to the bag. It will hit back if you get your head too close, so mind the rebounds. I have faithfully used these two for about 15 years. Awesome after a long day, go beat the shit out of something that won't care.

You can also get going on a heavy bag, but you can easily dick up your shoulders with one if you don't know what you are doing.