If you use your hands in a repetitive fashion at work or at play and notice your hands and wrists are feeling achey and fatigued, it’s partly because the muscles in your hand are out of balance. Usage of the hands is predominantly a flexion action, where the flexor muscles of the arm contract to bend the fingers inward. This is true for gripping and typing.
So what happens is that the extensor muscles of the arm, which are the ones that straighten out the fingers and bend the wrist upwards, are “overwhelmed” by the action of their reciprocal muscles, the flexors (flexor digitorum, flexor carpi ulnaris and radialis). The action of the joints in a flexor-dominated repetitive activity puts excessive wear to the same, small area on the joint surfaces and can gradually lead to stiffness and pain in the hands. And, it de-conditions the extensor muscles over time; meaning, makes them weak and less responsive. That explains the fatigue factor.
The solution is to do exercises for the extensor muscles to counteract the amount of flexion you do. A simple yet effective exercise is to use a thick rubber band (like the ones that hold together broccoli in the grocery store) and place it around your fingertips and thumb. Open your hand (extend your fingers till they are straight at the knuckles), about one repetition per second. Do about 50 every hour, four hours per day; depending on how much you use your hands. What you’re trying to do is work the extensors as much as your flexors to ensure both groups are getting an equal amount of work out. This will keep the hands strong and resistant to weakness and pain from frequent use.
