|Image from the Graphic Fairy|
I tried to use these methods the other night and discovered you really can't do one without using them all. I was playing Igor, who can be uncomfortable to play sitting down; and keeping my plucking hand's wrist straight was absolutely impossible unless I was keeping my arm up with my shoulder.
I've been in physical therapy for most of my childhood, I know the shaking from weak muscles well, but that was the first time in my life I felt it in my upper body. [And it was instantaneous, which is rare.] I've always known I had low muscle tone in my upper body, but this was the first time it slapped me in that face like that. Hell sitting down I couldn't last playing for three minutes.
[I set down with the new guy and he was much more comfortable to play seated.]