By Stephen E. Alway, Ph.D., FACSM
The front (anterior) part of your upper arm has two major muscles. The biceps brachii muscle is composed of two heads.2 The short head of the biceps attaches to the front part of the scapula bone or “shoulder blade,” and it runs along the medial (inner) part of the humerus bone of the arm. The long head of the biceps attaches on the scapula just above the shoulder joint, and it runs along the lateral part of the humerus to the elbow. The short and long heads of the biceps brachii come together to form the bicipital tendon. The bicipital tendon crosses the anterior part of the elbow and it inserts into the radius bone just a little beyond the elbow joint. Both biceps heads flex the elbow at the forearm2 (bring the hand towards the shoulder). However, because the bicipital tendon attaches to the radius bone of the forearm, which can pivot at the elbow joint, contraction of the biceps muscle can pivot the radius and supinate the hand (turn the palm towards the ceiling). The ability to supinate the hand makes the standing dumbbell curls superior to machine curls.
The brachialis muscle is deeper than the biceps brachii muscle, but it is just as important. It attaches along the anterior side of the humerus bone and it crosses the elbow joint anteriorly to connect to the anterior side of the ulna bone of the forearm near the elbow joint.2 The ulna does not pivot, so the brachialis muscle is an effective flexor, whether the hand is supinated or pronated. The brachioradialis is a forearm muscle, but because it crosses the elbow joint, it can be very active during dumbbell curls to help flex the elbow. It begins on the lateral side of the humerus bone above the elbow joint. It runs all the way down to attach to the radius bone of the forearm near the wrist joint, but it does not cross the wrist and therefore it only flexes the elbow joint.2
Standing Dumbbell Curls
1. Pick up two medium weight dumbbells and if possible stand in front of a mirror (to watch your exercise form). Place your feet about shoulder-width apart. Turn your hands so that the palms of your hands are semi-pronated (i.e., with palms facing the side of the thighs).
2. Flex the elbow of one arm so that the dumbbell moves closer to your face. After the dumbbell has moved upwards past the hip, begin turning the palm of the hand towards the ceiling (supination). The upper arm should remain perpendicular to the floor as you are curling the weight upwards. Try to keep the arm in close to the side of the ribs.
3. Continue to supinate the hand further as you curl the weight upward towards your face. Do not let your elbow travel forward more than a few inches at the top.
4. Slowly lower the weight towards the floor while at the same time you are reversing the hand position back to its semi-pronated starting position. Be careful that you do not hit the thigh with the dumbbell on the descent of the weight.
5. Alternate the contractions between arms until your set is completed. Replace the weight on the floor after the set is finished.
The semi-pronated starting hand position maximally activates the brachialis and the brachioradialis muscles at the start of the movement. However, when the hand becomes supinated, the biceps make a much greater contribution to the exercise. This is the perfect combination for activating all of the upper arm muscles. You should try to do the exercise with a controlled velocity,3 but without “cheating” by swinging the hips to help thrust the weights upward. If you cannot maintain good form during the exercise, you should choose a lighter dumbbell.
Start with only 1 set for the first week; otherwise your arms may become sore afterwards.4 However, work up to 3-4 sets of 10-12 repetitions5 over the following several weeks.
1. Coke LA, Staffileno BA, Braun LT et al: Upper-body progressive resistance training improves strength and household physical activity performance in women attending cardiac rehabilitation. J Cardiopulm Rehabil Prev 2008;28:238-245.
2. Moore K.L, and A.F. Dalley. Clinical Oriented Anatomy 4th Lippinot Williams Philadelphia, 1999; pp. 720-756
3. 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 2009;23:1670-1676.
3. Simao R, Spineti J, de Salles BF et al: Comparison between nonlinear and linear periodized resistance training: hypertrophic and strength effects. J Strength Cond Res 2012;26:1389-1395.
4. Radaelli R, Bottaro M, Wilhelm EN et al: Time course of strength and echo intensity recovery after resistance exercise in women. J Strength Cond Res 2012;26:2577-2584.
5. Matta T, Simao R, de Salles BF et al: Strength training’s chronic effects on muscle architecture parameters of different arm sites. J Strength Cond Res 2011;25:1711-1717.
6. Dunsky A, Ayalon M, Netz Y: Arm-curl field test for older women: is it a measure of arm strength? J Strength Cond Res 2011;25:193-197.