Jeff - here is a tip that a good friend / long time paddler shared: http://www.endlessriveradventures.com/kayakingblog/?p=1154

And another thought: hip snapping is not a strength thing. If you take the concept of a rubber band, the more you stretch it the better it snaps - big and little rubber bands alike. So if you attach a rubber band from one's ear to their hip, the more they can "stretch" that band, the snappier the hip snap. So improving a paddler's ability to arch around in the initial position, the more powerful the hip snap will be. Something to play with....