I'm wondering this because I might be using the keyboard and touchpad in a different way than others, but naturally for me, as in: the path of least resistance.
For scrolling, my right forearm points at the touchpad in a 45 degree angle, my middle finger touches the pad and I move my whole hand at the wrist to scroll. So all the middle finger does is touch the pad and raise again.
I use my right index finger for pointing. To move the cursor up & down I do the same as for scrolling, only with my index finger. For left & right I do what would look like pushing a marble to move the cursor left and the reverse to move it to the right. So my index finger really points (mostly) to the left side (depending on forearm position) and expands in it's natural path.
Regarding heavy keyboard use you often hear about the emacs pinky when somebody over years strenuously used their pinky to hold the control key down.
Well, I've noticed that I press control with the finger nail of my pinky and alt with the nail of my thumb. I'm sure it's unusual and it looks a bit funny, but it's completely natural to me and not strenuous at all.
