Great topic! I recently enrolled in a cello class after having played violin and viola since I was a child. Since my arthritis and carpal tunnel often make playing the violin and viola uncomfortable — difficult to reach viola C string on a full-size viola — I thought that playing the cello would be less painful. As it turned out, left-hand technique WAS less difficult, but for some reason I got cramps in my thumb joint holding the bow. Due to time constraints I had to drop the cello lessons, but I almost think I could make a go of it playing the cello.