to get more potential energy that means more kinetic energy so they can trow itfaster etc.
It sounds like your weight may be too far forward when you release the ball. Try keeping your body more upright and behind your left knee (for right-handed bowlers).
Those German Bowlers - 1915 was released on: USA: 14 January 1915
In tenpin bowling, bowlers who are having difficulty with release, usually related to the ball sticking on the thumb, will sometimes have a very small hole drilled just below the thumb hole, at angle that enters into the lower part of the thumb hole. This is to allow air into the lower region of the thumb hole and prevent a vacuum from taking hold.
Sliced - 2010 Bowling was released on: USA: 2010
The Bowling Alley - 1920 was released on: USA: April 1920
Bowling Tricks - 1948 was released on: USA: 10 January 1948
Better Bowling - 1942 was released on: USA: 22 January 1942
The Bowling Fiend - 1910 was released on: USA: 26 December 1910
Bowling Headliners - 1949 was released on: USA: 2 January 1949
Capcom Bowling - 1988 VG was released on: USA: August 1988
Ten Pin Bowling - 1988 VG was released on: USA: 1988
3-D Bowling - 1978 - VG was released on: USA: 1978