Proper fit of a bowling ball is very important to skill development. Most beginner bowlers will place their hand in a house ball as it sits on the rack (hand on top of the ball) and then pull the fingers and thumb out all at the same time. If the holes feel too tight, they will find a ball that has bigger holes. This will result in a poor fit because of two reasons:
When selecting a house ball, start by finding a ball that is an appropriate weight for your age and strength. A good rule for younger kids is to pick a ball weight that is equal to the age of the child (the lightest is 6 points). Most men and teen boys will use a weight between 12 and 16 pounds and most women and teen girls will use a weight between 10 and 14 pounds. Ball weight and ball fit may need to be compromised to get the best option available when selecting a house ball.
The first thing to look for in the fit of a ball is to choose one with the proper thumb size. You should feel a slight drag on the sides of the thumb for a proper fit.
Next, check the distance between the fingers and thumb (span) by placing your thumb in the ball and laying your fingers across the finger holes. With your thumb all the way in the ball and your hand relaxed on the ball, the second joint line on your fingers should be approximately ¼ inch past the front edge of the hole.
Make sure the fingers fit in the ball to the second joint.
Because house bowling balls are not fit to the bowler’s hand, you may need to compromise some elements of a proper fit. The thumb size is the most important followed by the span. The least important is the size of the fingers and can be on the larger side if necessary. If the thumb fits properly, the fingers cannot come out of the ball first, so a ball with slightly larger finger holes will not cause the bowler to drop the ball during the swing.
To reassure the bowler the ball will not hang up on the hand, have someone hold the ball while you place the fingers in first and then the thumb. Turn the bowling hand so it is under the ball and slightly to the side.
With the hand relaxed, have the assistant roll the ball away from the thumb and then the fingers. This will assure the bowler will be able to release the ball if they use minimal grip pressure on the ball. Think of the ball as a raw egg or live bird in your hand – don’t squeeze it!
It is important to understand that when the ball is in motion (swinging), it takes very little grip pressure to hang on to the ball. A proper fit will allow the bowler to maintain light grip pressure developing a free pendulum swing that is created by the weight of the ball.