A friend who just had SRS had sore elbows and was scratching her head why this was so.
I had to laugh, I had figured it out already.

Lie down in bed.
Now get up without using any stomach or leg muscles.
You'll find that you initially force yourself up using your elbows.
As your upper body angle changes you slide your elbows along the bed.
Result: sore elbows.

It seems to me that having reduced arm functionality from simultaneous BA would make maneuvering even harder.