Muscles Targeted: Hammer dumbbell curls primarily target the biceps brachii (2 headed muscle of the upper arm) brachioradialis (forearms) and the brachialis (front of the upper arm). The secondary muscle groups targeted include the anterior deltoids, and to a lesser extent, the coracobrachialis and upper pectorals.
Exercise Instructions: This is virtually the same exercise as the dumbbell biceps curls except that you keep your wrists in a fixed or locked position throughout the movement with no supination (twisting of the wrists). You can perform this exercise by either standing or sitting on a bench, whichever you prefer. Grab a dumbbell in each hand with a secure grip and let your arms hang naturally down at your sides. Slowly curl the dumbbells simultaneously up to the top. While you are performing the movement, keep your wrists locked with your thumbs pointing up. Be sure to squeeze your biceps for a one-count at the top of the movement. Slowly lower the dumbbell back down to the starting position and repeat.
Why This Exercise is Important: Hammer dumbbell curls is one of the most popular arm exercises people perform at the gym. For good reason, since it’s probably the best exercise for building the biceps and forearms. After seeing the iconic images of top Olympian bodybuilders like Arnold Schwarnegger and Ronnie Coleman with their incredibly massive arms, many bodybuilders put a lot of emphasis on exercises for their biceps, thus making hammer dumbbell curls a staple in any workout routine. At the same time, this exercise is relatively easy to perform and requires minimal equipment. All you need is a couple of dumbbells (even one will do, just alternate on each side) and you’re good to go. You don’t even need a gym as this can be performed just about anywhere. You can do them at home, in a hotel room and even at the office. The best thing about it is that it places less stress on the wrists than barbell curls since you’re not supinating (twisting) your wrists as you curl the dumbbells up to the top.
Things To Avoid: As with all exercises, solid technique is very important. Hold a pair of dumbbells at thigh height so that your palms face each other and your thumps are up. Whether sitting down or standing up, keep your back straight and your feet shoulder-width apart. If standing up, relax your knees to protect your lower back. Maintain your posture as you perform the exercise and avoid hunching over. Adhering to strict form will help emphasize the movement on your forearm muscles as well as the muscles underneath the biceps.
Start with the dumbbells lateral to your thighs, maintaining your thumbs-up position all the way throughout the movement, and flex at the elbow until you reach the top position. Draw power from your arms, not your upper body. Don’t just straighten your arms and let the dumbbells drop back down quickly. Moving too fast will reduce the amount of time your muscles are under tension thus decreasing the training effect. Nor should you curl all the way to your shoulders. Choose the weight of the dumbbells carefully, ones that are not too heavy nor too light. Using weights that are too heavy will result in improper technique and body positioning, and also reduce your range of motion. Avoid the common error of using a rocking motion at the torso to assist in lifting as this will also reduce the effectiveness of hammer dumbbell curls on the targeted muscles. Those with elbow problems should avoid doing this exercise, while those with lower back problems should do this sitting down.
Reps and Sets: For beginners, start with 8-10 reps for 1-2 sets of hammer dumbbell curls. As you progress and become adept, increase your reps and sets. However, avoid overtraining the biceps. Only train your biceps once per week for optimal results. Consider your entire program and keep your overall volume for biceps lower than for other larger muscle groups like your back and legs.
Other Exercises To Use: There are many exercises you can choose in tandem with hammer dumbbell curls. You can opt for free weight barbell biceps exercises such as EZ bar curls, reverse grip barbell curls, or you can opt for machine cable exercises like cable preacher curls, cable rope hammer curls and standing cable curls. View our extensive database of exercise guides for a comprehensive list of exercises that target the biceps.