Speed On Heavy

A good speed workout on a heavy-bag can be done by simply doing what you do when your shadowboxing you want to throw snapping, short, quick punches.  If you hit the bag with nothing but hard strikes your only going to get power so you need to hit the bag with taps in small combinations or single strikes.  It does not matter what strikes you use just don't use the ax-kick, toe-kick or uppercut on the heavy-bag.

Shadow Striker

When your shadowboxing you do not want to fully extend your arms or try to punch hard as if your using a heavy-bag you want to relax your arms and give a short snapping punch.  It's also good to do this with weights or even resistance bands.  When you practice shadow-kicks it's the same short snaps and always follow by the way your body performs not how the style tells you.