The Anatomy of a Stop Shot

By Steve Jennings

The term cue ball control refers to the ability to get the cue ball to stop moving in a place that provides the best opportunity to make the next shot successfully. To do that, it is critical to know the natural tendency of the cue ball after it contacts an object ball. Some very absolute laws of physics determine this. An object in motion will stay in motion until acted upon by outside forces. Rotational and directional energy both affect energy transfer, as does velocity. Gravity and friction are also factors to consider.

Let’s start with the simple straight-in shot. The cue ball rolls straight toward the object ball. When they impact, some energy is immediately transferred to the object ball, setting it in motion. At that instant, the cue ball stops. If all of the energy is transferred to the object ball, the cue ball remains motionless. This happens when there is no directional or rotational energy remaining within the cue ball. With a direct impact, all of the directional energy is transferred. However, if any rotational energy remains, the cue ball will start moving again.

So what is rotational energy? Quite simply, it’s the spinning of the ball as it moves. That spin can be sideways, backspin, or just natural forward roll, or any combination. The type of spin will determine where it goes, and the amount will determine how far. The only way to make the cueball stop is to have no backspin and no forward roll upon contact.

Place a striped ball on the table with the stripe facing side to side and shoot it down table. If you hit it above center, you can see it will have forward roll all the way down. If you hit it below center while staying on the vertical centerline, it will start with a backspin, which will decrease as it travels until it finally changes to a forward roll. This loss of backspin is a result of gravity and friction. The point where it changes is called the skid zone. At that point, it has neither forward nor backward roll or zero rotational energy.

On a straight-in shot, and ONLY on a straight-in shot, if the cue ball contacts the object ball while in the skid zone, the result will be a dead stop shot. You can push the skid zone further down the table by either increasing the speed of your shot, or striking the cue ball lower, or both. Again, you can only achieve a stop shot when shooting a straight in shot. Any cut angle will cause the cue to drift off in the opposite direction of the cut angle. Any forward roll will allow the cueball to follow the object ball, and any backspin will cause the cue ball to reverse direction and draw back.

Practice using the stripe ball exercise and varying the stroke speed or how much bottom spin you apply until you can accurately predict how far down table your skid zone will occur. Then set up straight in shots at different distances and learn to hit stop shots at different distances.

The stop shot is often considered to be the most important pool shot you can learn. Master it, and you’ve made the first step toward cue ball control.

Good luck!