Pronation and Supination Twist
This exercise, also called the wrist twist, requires you to twist your entire forearm to go from the palm up to the palm down position. While standing, pick up a dumbbell or a hardcover book that weighs at least three pounds with your left hand. Straighten your back and legs. Bend your elbow 90 degrees so you are holding the object out in front of you with your fingers parallel to the wall. Rotate your forearm so that your palm becomes parallel to the ground. Hold for five seconds. Rotate your forearm a full 180 degrees. Hold for five seconds. Continue until your arm is fatigued. Do three sets for each arm.
This exercise involves twisting a towel, but it's your forearm and your fingers that get the workout. Dampen a hand towel or dish towel so that it is heavy with water but not dripping. Roll the towel into a log shape. Grip this "log" in both hands using an overhand grip. Squeeze and twist the towel moving your left hand toward you and your right hand away from you, trying to wring the water out. Switch the direction of your hands after 60 seconds. Continue until all the water is out of the towel. Do this once a day, preferably over a tub or sink.
Seated Forearm Twist
This exercise works the brachio-radialis muscle in your forearm, which terminates near your elbow. Sit down on either a bench or a chair and bend your knees at 90 degrees. Pick up a dumbbell in each hand. Hold them so that one end of each dumbbell faces the ceiling and your knuckles face the walls out to the left and right, respectively. Bend your elbows at 90 degrees so that your forearms lightly brush the tops of your thighs. Twist both forearms as far right as you can at exactly the same time. Return your arms to center. Then twist them to the left. Hold at the end of each twist for five seconds. Do not twist at your waist. Do one set of 16, alternating sides.