With dumbbells, you can build mass in all the major muscle groups in the arms, which include the biceps, triceps and shoulders. Building muscle size requires a high-volume workout; each exercise must really overload your muscle fibers to be effective. Using weighted dumbbells or a pair of adjustable dumbbells is a fantastic way to build strength in your arms.
Perform two arm workouts weekly, with two days off between each one. Just as important as your high-volume workouts is allowing your arm muscles enough rest so that they can thoroughly complete the recovery process. Giving the muscles the recovery time they need helps build strength faster and keeps the workout safe.
Begin each workout with a five- to 10-minute dynamic warmup, which consists of a few minutes of light aerobic exercise such as walking or cycling, followed by movements specific to the upper arms. Arm circles, arm swings across your body and pushups against a wall will increase blood flow to muscles surrounding your shoulder, elbow and wrist joints.
Do the following exercises for your shoulders (the top of your arm), biceps and triceps. Complete three to five sets of about eight to 12 reps of each of these, using a weight that will make you hit fatigue before the 12th rep. The weight that will cause you to reach fatigue within eight to 12 reps will likely vary between exercises, and you'll know you've reached fatigue when you begin to lose form. If you're able to complete the final two reps in a set without reaching fatigue, it's time to increase the weight you're using.
Include shoulder presses and upright rows, which are effective at developing the shoulders. To perform a shoulder press, hold the dumbbells at your shoulders with your palms facing forward and then press the weights overhead until your arms are extended. At the top position, the dumbbells should be directly in line above your ears. Lower your arms and bend your elbows to return the dumbbells to your shoulders. Upright rows involve holding the dumbbells down in front of your legs and then pulling them up to your upper chest by bending your elbows and allowing them to flare out to the sides. Lower your arms and extend your elbows to return the weights back to the front of your legs. To increase exercise effectiveness and reduce the stress on your shoulders, keep the dumbbells close to your torso as you lift and lower them.
Incorporate biceps curls and in-and-out curls to develop your biceps. To perform biceps curls, stand with the dumbbells down by your side and palms facing forward and then bend your elbows to curl the weights to your shoulders. Straighten your elbows to lower the dumbbells to starting position. In-and-out curls are similar, except that you alternate between curling the dumbbells straight forward and curling them while your chest is slightly open, so your hands are wider. During both exercises, keep your elbows close to your torso and avoid rocking in an attempt to utilize momentum to lift the weights.
Target your triceps with the overhead triceps extension and close-grip bench press. For an overhead triceps extension, hold one dumbbell over your head with both hands and with your arms straight. Bend your elbows to lower the dumbbell behind your head. Extend your elbows to return the dumbbell to over your head. Your upper arms will want to slide toward your head as you lower the dumbbell, but movement should be isolated to the elbow. Your upper arms should remain vertical throughout the exercise. The close-grip bench press is performed while lying on a flat bench with your arms extended over your chest (at a 90 degree angle to your body), palms facing each other. Keep your elbows close to your torso and lower the dumbbells to your torso. Lift your upper arms and extend your elbows to push the dumbbells back up.
Finish each workout with a cool-down period of static stretches. Stretch your shoulders by bringing one arm across the front of your torso and using your free hand to pull it in toward your chest. Hit your triceps by lifting one bent arm overhead and using your free hand to pull back on your bent arm at the elbow. Be sure to stretch both sides evenly. To stretch your biceps, with your arms down by your side and your elbows straight, lift your arms back behind you.