Your hands, wrists and forearms are usually on intimate terms with the instruments of your sport. You need a powerful set of muscles there to execute a winning swing with a racquet, bat or golf club, to spike or slam dunk the ball or to lift that weight.
Building your forearms can also prevent such injuries as tennis elbow (which can happen in any sport, or even while you're hammering nails).
Your grip must be firm during this kind of contact so the vibrations generated (from an off-center hit) won't travel up your arm. A solid, tight grip ensures that the shock is absorbed by the hand and forearm muscles.
Work your hand, wrist and forearm muscles into solid shape and get a firm hold on forearm fitness.
Kinesiology & Physiology
With the muscles of the forearm, it's impossible to separate grip from wrist action. Your flexor digitorum profundus (1) curls your fingers; the extensor digitorum (2) unfolds your fist into an open palm, the flexor carpii radialis (3) and ulnaris (4) move the palm in any direction toward the forearm,- the extensor carpi radialis longus (5) and brevis (6) move the back of the hand toward the forearm.
The supinator (7) rums the palm upward, while the pronator quadrafus (8) and teres (9) turn the palm downward. All of these, and many more, are constructed around two forearm bones, the radius (10) and ulna (11). At the lower end, they form part of the wrist joint, and at the upper end, the elbow joint. The point of your elbow, the olecranon (12), is an extension of the ulna.
These work the muscles that control wrist flexion. Place your forearms on a bench or on your knees. Grasp a barbell using an underhand grip. Let your hands drop down into a hyperextended position while holding a weighted dumbbell or barbell. With your elbows and wrists the same distance apart, lower the weight until you can't lower it any farther, letting the bar roll down your fingers. Roll up with your fingers, keeping your forearms on your knees and raise the weight as high as possible. Slowly lower it and repeat.
Wrist Curl Demonstration
Reverse Wrist Curls
For wrist extension and hyperextensiom do this version of the exercise. Start in the same position as the wrist curl, but with an overgrip on the bar so that you begin in a flexed-wrists position. Raise the bar up as high as possible into the hyperextended wrist position. Then slowly lower the weight and repeat.
Reverse Wrist Curl Demonstration
AKA Plate Pinch
Take an overhand grip on a 45-pound weight plate, and let it rest up against your thighs for support. Hold the weight in your fingertips and open your hand as much as you can without dropping the plate. Then close your hand, squeezing your fist tightly, and repeat.
Plate Grab Demonstration
Every time you open a door, use a screwdriver or put spin on a ball, you pronate or supinate your hand. Stand with your forearms held at a 90-degree angle to your upper arms. Grasp a dumbbell weighted on one end (a Thor's hammer) with an underhand grip, Rotate the bar to a palm's-down grip, return to the initial position and repeat. You should be able to go through a 180-degree range of motion.