Sharpen Your Biceps Peak with Incline Dumbbell Curls

By Stephen E. Alway, Ph.D.

The holidays have passed and winter is quickly on its way out.  Now is a great time to take stock of your current physical goals for the summer. If one of your New Year’s resolutions was to be the proud owner of harder and more peaked upper arms this summer, it’s not too late to launch into a revised arm program. The best way to do this is to focus on activating the outside (long head) of the biceps brachii muscle of the upper arm. It turns out that incline dumbbell curlsare perfectly designed to sharpen and increase the peak of your biceps, because they strongly activate the long head of the biceps brachii. This makes incline curls an ideal exercise for both thickening and increasing the peak in your upper arms.

MUSCLES ACTIVATED BY INCLINE DUMBBELL CURLS

Incline dumbbell curls activate both heads of the biceps brachii muscle; however, the long head of the biceps gets the greatest benefit from this exercise. The long head begins on the supraglenoid tubercle of the scapula (a bump over the glenoid fossa of the scapula), and it crosses the shoulder joint. It has a very long tendon, and but a shorter muscle belly than the short head of the biceps brachii. The belly of the long head of the biceps sits on the lateral part of the arm, and its fibers combine with the short head as both sets of muscle fibers extend toward the elbow.

The short head of the biceps begins on the coracoid process on the anterior part of the scapula (shoulder blade). It extends down the medial (inner) part of the humerus bone and together with the long head of the biceps, forms the thick bicipital tendon. This tendon crosses the anterior part of the elbow joint to anchor on the radius bone of the forearm just past the elbow joint. Both the long and the short heads of the biceps are strong flexors of the forearm. However, because the bicipital tendon inserts on the laterally positioned radius bone of the forearm, the biceps also acts to supinate the hand (turns the palm toward the ceiling), when it contracts. The long head of the biceps can also provide a small amount of force during shoulder flexion (i.e., bringing the arm forward).

The brachialis muscle lies deep to the biceps brachii. It begins on the distal half of the humerus and it inserts on the coronoid process of the medially placed ulna bone of the forearm. Although it has no supination function, it is a very strong elbow (forearm) flexor.

INCLINE DUMBBELL CURLS

Adjust the incline bench to about 60°. Place the bench in front of a mirror so that you can closely watch your exercise form.

Sit on the bench, then lift the dumbbells off the floor, one at a time. However, if you have a weak or injured lower back, you should avoid flexing your torso to pick the weight off the floor. Instead, have a partner lift the weights and hand them to you when you are seated. Make sure your lower back is pressed firmly against the bench.

In the starting position, your arms should hang directly down toward the floor. This will form a line that is perpendicular to the floor, which extends from the humerus bone of the upper arm, through the elbow to the hand holding the dumbbell.

Turn the dumbbells so that the palms holding the weights are facing each other. The hands will then begin in a semi-pronated position and this unwinds the biceps.

Flex the elbow of your right arm and begin pulling the dumbbell up the shoulder. As the right hand starts to move, and after the dumbbell clears your hip, begin supinating the palm. This will turn the palms toward the ceiling as the dumbbell is pulled upward toward your shoulder.

At the top position, tighten your biceps hard and hold this voluntary contraction for two seconds. Relax the contraction, then slowly lower the weight toward the floor. Uncoil the forearm so that the palm is turned in a semi-pronated position as the elbow is straightened at the bottom (starting) position.

Immediately switch to the left arm, and repeat the contraction upward in the same manner, by curling the weight upward and supinating the hand, tensing at the top, and then lowering it slowly under control. Continue alternating between arms until the set is complete.

The incline bench pushes the shoulder into extension, and this stretches the long head of the biceps. This causes a preferential activation and contribution of the long head of the biceps in the incline curl. The short head of the biceps is still activated, but just not quite as much as the long head of the biceps. The addition of the supination activates both heads of the biceps very strongly. The brachialis muscle is activated throughout each contraction.

The isometric contraction at the top of each curl will add significantly more intensity to the exercise. This will cause your biceps to fatigue more quickly. That means that you will really have to dig deep into your soul to work up the resolve to complete each set. Nevertheless, this momentary pain is well worth the outcome of reaching your goal of higher and more peaked arms.

Incline dumbbell curls are not a technically difficult exercise. However, simplicity has nothing to do with being easy. This is a very intense, but rewarding exercise. This version of the curl will attack both heads of the biceps— especially the long head. Your arms will take on a greater peak and be harder and denser than you thought would be possible. While January may not seem like an exciting month, if you use this month to start your renewed biceps training, it can be the exciting beginning to your transformation from average arms to peaked biceps.

REFERENCES

Bazzucchi I, Sbriccoli P, Marzattinocci G and Felici F. Coactivation of the elbow antagonist muscles is not affected by the speed of movement in isokinetic exercise. Muscle Nerve, 33: 191-199, 2006.

DeFreitas, J. M.; Costa, P. B.; Ryan, E. D.; Herda, T. J.; Cramer, J. T.; Beck, T. W. Innervation zone location of the biceps brachii, a comparison between genders and correlation with anthropometric measurements. J Electromyogr Kinesiol, 20:76-80; 2010.

Ingebrigtsen, J.; Holtermann, A.; Roeleveld, K. Effects of load and contraction velocity during three-week biceps curls training on isometric and isokinetic performance. J Strength Cond, Res. 23:1670-1676; 2009.

Linnamo V, Strojnik V and Komi PV. Maximal force during eccentric and isometric actions at different elbow angles. Eur J Appl Physiol, 96: 672-678, 2006.

Standring, Susan, Gray’s Anatomy, text, 39th edition, CV Mosby, Churchill Livingstone, 2005, ISBN: 0443071683

Illustrations by Wm. Hamilton, CMI