During a bowling game, the ball rotates through a series of phases. Understanding each of these phases can help you adjust your technique to improve your chances of a good strike.

Skid Phase

The skid phase of a ball rotation is when the bowling ball starts to slide down the lane. The bowling ball does not have the speed to match its rotational speed, so it will skid until lane friction slows the skid and pure rolling begins. This happens in the last 15 feet on the lane, as the bowling ball rolls down the lane towards the pins. It is important to keep your ball speed consistent so it doesn’t get ahead of itself and start sliding backwards or hooking too soon. Friction causes the bowling ball to lose axis rotation and tilt during the skid phase. A bowling ball that is thrown with high amounts of axis rotation will take longer to transition from skid to roll than one that is thrown with low axis rotation.

Hook Phase

In the Hook Phase of a ball rotation, friction begins to change the ball’s axis of rotation. The ball is losing a large amount of energy in the hook phase and will not be able to travel as fast as it would otherwise. In this phase, the ball is starting to pick up tiny amounts of friction that are already in the lane. These frictions start to turn the axis of rotation of the ball back in line with its trajectory and the ball will slow down significantly as it passes through the break point.

Roll Phase

Bowlers use ball speed, rev rate, axis tilt, and axis rotation to control the roll phase of a ball’s rotation in bowling. Once the ball enters the roll phase it will no longer hook and its axis rotation and axis tilt will decrease slowly as it travels down the lane. It will also reach its maximum rev rate at this time. Axis rotation is the horizontal measure of a ball’s revolutions and is determined by the bowler’s release technique. Generally speaking, the more axis rotation you have the less the skid phase will last and the ball will be able to roll down the lane more easily.

Entry Angle Phase

The entry angle phase of a ball rotation in bowling involves the adjustment of the ball’s direction as it enters the pocket. This is important for ensuring that the ball ends up in the correct position to make a strike. The optimum entry angle for a pocket strike is about six degrees from straight-on and two inches to the side of center. The simplest way to calculate this is to draw a line at six degrees from the center of the head pin toward the pocket (as shown in Figure 2 above). Then another line that offsets right by two inches parallel to the first.

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