Change of direction quickness is important in any sport, but especially in basketball. The 2 step back cone drill is a great basketball workout for developing backwards to forwards change of direction speed. In order to be quicker or faster the player needs to be efficient with their movements. If they are wasting motion when they move, than they are going to be slower. So when you watch the video make sure that you are learning the correct steps to the drill.
The below video will show you how to execute this quickness workout and also show you the proper technique. Be efficient in your movements, but once you learn the correct steps and movements you want to push yourself and challenge yourself to go as fast as you can (with good form).