Since using both of these quite intensively, I have developed what I think is trackball-specific RSI – a sharp pain in the muscle group up at the elbow end of the forearm, when I make certain movements which involve grip with the middle (longest) finger.

Watching what I do when trackballing, it looks as if quite a lot of the fine movement with a ‘ball is done with the arm frozen in tension and the index and middle fingers moving very slowly, also in tension – which gets a lot worse when dragging. It could be that I’ll have to go back to the good old mouse to give my arm a break: at least, it’s that or buy that first sign of decrepitude – a shopping trolley…