Ouch. I'd assume she would have back problems by now. :S Ah well so long as she likes to play with them. I'd hate to run with those things personally though!
I'm kinda surprised she hasn't done any anal or ducking on camera. Sure the blow jobs are good, but there needs to be more to stop it from getting boring.
Also I've never seen her give a titfuck. Seems a waste not to do them with that huge rack she carries around.