The most serious problem caused by jumping up, in my opinion, is that it affects the length and smoothness of the follow through. There are a few things I try to do to not jump up since it is one of my bad pool habits- 1. Practice a very long (exaggerated) follow through on all shots to prevent jumping up. 2. Keep your head down and concentrate on keeping your head down until all balls stop rolling on all shots in practice for approximately 100 shots or so to get the habit ingrained. 3. On shots where you know you will need power (and hence sometimes that will cause jumping), start in a stance with your head a little higher- I normally play best with my head very low near the surface of the table but in power shots try to start a little higher to give some more room for the power follow through stroke. I hope these tricks help.
Stay down until the cue ball stops rolling. It’s that simple.
Earl uses heavy arm weights. If your head bobs a lot you might try a diving bell, they pretty heavy.