The two groups of muscles in your wrists are the extensors and flexors. You can strengthen them all with weight training exercises. The wrist extensors consist of eight muscles and work to extend your wrist and move your fingers. The wrist flexors have six muscles that function to flex your wrist, fingers and elbow.
Use a dumbbell for the wrist curl, which targets your wrist flexors -- the muscles in your inner forearm. You can do these curls one hand at a time or with both hands at once. Begin by holding a dumbbell in each hand. Kneel on the floor with your forearms resting on a weight bench. Hold the dumbbells in your hands with your palms facing upward. Position your arms so that your hands hang just over the edge of the bench. Bend your wrists down until you feel them stretch. Slowly raise your wrists back up as high as you can until you feel a stretch in your flexors. Maintain a firm grip on the weights throughout the exercise to avoid possible wrist injury. Start with a low number of repetitions, and work your way up to 10 or 12.
The wrist extension curl targets the wrist extensors -- the muscles in your outer forearm -- and requires dumbbells and a weight bench. Begin by kneeling on the floor with a dumbbell in each hand and your forearms resting on the bench. Position your arms so that your hands hang over the edge of the bench with your palms facing down. Lift your hands up as high as you can until you feel a stretch in your wrist extensors. Keep your inner forearms touching the bench at all times. Slowly lower and repeat.
The preacher curl mainly targets your biceps, but also works your wrist flexors, which act as stabilizers. Place the back rest of a weight bench at a 90-degree angle. Grasp a dumbbell in your left hand and rest the entire back of your arm on the back rest with your palm facing upward. Stand behind the bench and place your right foot behind your left foot to balance your body. Slowly raise the dumbbell toward your shoulder by bending your elbow. Lower and repeat.
The wrist roller primarily targets your wrist extensors but also uses your flexors to stabilize the movement. The exercise requires a weighted cable roller. Place the plate at the end of the cable on the floor and stand behind it. Hold the wrist roller handle in both hands using an overhand grip. The connecting cable should be fully extended. Twist the roller with each hand as you slowly lift the weight up by wrapping the cable around the roller. Once the plate reaches your hands, reverse your twisting direction to slowly lower the plate back to the floor. Repeat.