Punch bag training is a celebrated technique to enhance punch strength as well as speed and the basic fundamental lying beneath this is to start off by hitting the punching bags harder than you normally do! So, you punching bag should be weighing at least 100 pounds and note that a heavier bag forces and motivates you for a harder punch which in turn improves your punch strength. The ideal way is to begin with something lighter and then progress to a heavier one to gradually increase your stamina. And while maintaining this principle, keeping balanced is the key to keep in mind; one ought to be relaxed maintaining a proper posture and one should never over extend the body while hitting the punching bags! visit: www[dot]ultimate-mma-equipment[dot]com/adidas-bag-gloves[dot]html