I think this is actually a great question...and I have no idea at all how to answer it. I would assume Miss Renee and the APA may can answer that. I know when I played in the wheelchair tour of the NWPA that some guys actually could stand and walk some, they had partial paralysis but had to play from the wheelchair to include keeping both butt cheeks in the seat during all shots. For me, I didn't even like that rule cause I can stand up on my short legs a little and get a bit more leverage when breaking, but they seemed to not notice me doing that much.
As far as your question, I truly don't know what the rules are for the APA and wheelchair pool players. I just go bang balls around and like the sound of plunking as they fall.
Shorty