A curious thing is the amount of grip pressure that bowlers think they need to apply to the ball in the swing. Many bowlers think that they need to squeeze the ball to be able to throw it well. Others bowlers need to squeeze to hold on to it. Many just need to understand appropriate grip pressure to bowl better. In either case, squeezing, or excessive gripping, should not be necessary and is a detriment to performance.
Some bowlers squeeze to apply extra pressure from the fingers and at release.
While this may seem to enhance the release, it usually weakens it. Since a clean thumb release is essential to create rotation and revolutions from the fingers, the more relaxed the hand and the cleaner the thumb release, the better. Lift and rotation are a function of ball fit and leverage, not pressure. Squeezing to hold on to the ball is a very serious problem. It is a detriment to performance.