The 5 yard cone crossover steps drill is one of the best basketball workouts for teaching lateral quickness and change of direction. In basketball lateral quickness is especially important in man to man on ball defense. When the offensive player makes a move you need to be able to slide over and cut them off, and then be ready to quickly adjust again in either direction.
It is really important that you focus on the footwork in this basketball training video because being quick has a lot to do with not wasting any motion when moving. The player should aim to be as efficient as they can in everything that they do, and playing defense is no exception.