Playing on the ball defense is all about staying low in a wide defensive stance, and being able to quickly slide laterally in either direction to cut off the ball handler when they go to drive the ball. The medicine ball defensive slides basketball drill, is going to work on the player staying low in a defensive stance, and also work on some conditioning as well.
The goal of this defensive basketball drill is to teach the player to stay low in a stance the entire time they are on defense, and then also give them the strength and conditioning in their legs to do so. For this basketball drill you don't have to go very long either. It only needs to go for 15-30 seconds before you rotate in the next player. That is what makes it great for practices or small group workouts where you have a set amount of time on the floor.