The Finger Extensors are situated in line with the back of your hand stretching up your forearm. One of the easiest ways to exercise your Finger Extensors is to buy a finger resistance band hand gripper which does exactly what you would expect. There are holes in which to place your fingers and your thumb with the natural position showing the band/hand as closed. Using the strength of your fingers, and your Finger Extensors, simply stretch the band by opening up your fingers and thumb, the return to the starting position and repeat. You will feel this exercise pulling on the back of your forearm as the Finger Extensors come into play.