Earlier quoted context omitted.
> You can move a finger a lot faster than a whole arm. If you're moving your arm to move your mouse, there is probably something wrong with your mouse.
If you're moving your arm to move your mouse IIRC I've always been old that I should move my whole arm with the mouse. The idea being that it's a small movement for your elbow/shoulder but a much larger movement for you wrist so you can avoid wrist injuries by moving your whole arm.
I mean, those same ergonomics guides also tell you to keep your back straight and your feet flat on the floor in front of you. How many people do that?