Ya it's time to do a serious reconsideration on my riding style, I swear I could be driven figure eights all day and hit double after double. Actually done it before. I just love that feeling of the double up pushing you straight up it's not so much how large you go but that feeling under your feet at take off just boosting you, IMO.
It's not even the flats really, both times I've jacked my knee it's been the same way, lazy cut at the DU without enough speed, land and board just kinda sticks and my upper body gets yanked forward. Gotta quit doing that!!