Ideally, I like to think of myself as a jumping frog, just doing so vertically.
I also neglected to mention that you should drive your knees out and concentrate on it throughout the lift. Be a jumping frog.[/quote]
I do this also on my heavy sets. I envision my self jumping with the weight on my back, and I really try to do so. Not only does it promote good form, it gives you a hell of a lot more drive / umph.
Squat down with no bar, and jump, video tape it, see how it looks. If you still look at the ground when you jump up, then fix it. If your ass sticks out, then you do a good morning with no weight, then figure out how to jump correctly before you try to squat.
If all good there, then take the bar, put it on your back, descend, and jump, just like you were before, in the air. Video tape it, and compare.
I used to incorporate jump sets with up to 3 plates, but it is too much stress on my spine.