To throw a good rise you really have to focus on slicing through release with the pinky in an attempt to get under the ball with your fingers. The early initiation or slow developing rotation of the forearm through release will doom a rise ball. So, learning the rise teaches a girl to delay the initiation of rotation. It's this delay keeps the load on the forearm for a longer period of time and causes a much more "violent" turning action causing better spin and speed eventually. My hypothesis is that this is where MANY (not all) girls learn to refine their whip.