Boxing is a sport that may easily hurt the hands, whether practicing on the heavy bag or boxing against an opponent. Hand wraps preserve the little bones in the hand from breaking, the skin on the knuckles from ripping, and they assist keep your wrists from spraining when you deliver a powerful punch. However, wrapping too tightly can be as harmful as not wrapping at all. As with any other exercise, proper form is essential when punching a heavy bag. If you're not used to hitting a heavy bag, start out slowly with no more than three punches per hand. The best hand wraps are thick strips of cotton or hemp cloth. They should be long enough to extend past the ends of your fists but not so long that they trail behind you if you throw a punch. Some people also like to use tape instead of hand wraps because it's easier to move back and forth between fingers while wrapping them. However, tape can be hard to remove later if you want to practice without having to re-wrap your hands. Hands need to be wrapped loosely enough for you to flex each finger individually, but not so loose that they slide around during a fight. Experiment with different levels of tightness until you find what works for you. You might even want to wrap one hand but not the other so you can see how it affects your fighting style.