HOW: For this exercise set up the specific piece of equipment in all of your finger tips and your thumb. Stabilize the end of your wrist with your other hand, then to perform the exercise spread your fingers away from one another while trying to straighten them at the same time. Return to starting position and repeat. This will be a very small movement.
FEEL: You will be working all of the muscles on top of your hand with this exercise.
COMPENSATION: Try to keep your forearm and wrist still (shaking is ok if the resistance is hard). However, try to only move your fingers and thumb and nothing else.