In order to have a good release, you need good timing. Your slide foot’s first step on the approach needs to occur in time with the ball start (i.e. the first step for four-step bowlers and second step for five-step bowlers).
The next place on the approach where timing is evaluated is the pivot step. The pivot step is the last step before the slide; at the compression of the pivot step, the bowling ball needs to be at the peak of the backswing at this point.
In this premium video, Scott Pohl, owner of On Track Pro Shop, shows how timing affects ball motion.
Late with the Ball
Late ball start to backswing results in pulling through the shot.
The bowling shoulder over-rotates and forces the hand to go around the ball. The ball travels inside of the target and desired ball path.
Early with the Ball
Early ballstart to backswing results in the bowling ball missing at the release and a loss of leverage. The bowling shoulder is ahead of the pivot step, resulting in an unintended consequence where you begin to turn the ball early in the backswing.
The ball never picks up and it stays outside.
When your ball start is in time with your backswing, you’ll have good leverage in the finish position and a good release. This results in good ball roll and proper entry angle into the pins for a strike.