By Stephen E. Alway, Ph.D.
The shoulder girdle is key to maintaining the physical configuration of your upper back and torso, and its strength and construction will help to establish the success of most of what you do with your upper body. If you thicken the lateral part of the deltoid, your upper body will also assume a more commanding shape because your upper back and chest will look wider from the front, and your waist width will appear smaller. Seated dumbbell lateral raises are exceptional for adding shape and mass to the deltoid muscle, without overly burdening the unstable shoulder joint.
The deltoid muscle covers the shoulder joint and several other muscles that work on this joint. This deltoid has muscle sections that arise from three general regions of the shoulder girdle.2 The anterior fibers of the deltoid (clavicular part) connect the lateral part of the clavicle to the humerus bone of the upper arm. The anterior fibers flex the humerus bone by bringing the upper arm forward.3,4 The posterior fibers of the deltoid (scapular part) begin along the posterior spine of the scapula and connect to the humerus bone. These fibers extend the humerus by pulling the arm backwards (posteriorly). The medial fibers of the deltoid (lateral part) are strongly activated by seated lateral raises. They attach the acromion of the scapula to humerus bone. These fibers are anatomically located in the medial region of the deltoid (with respect to the other fibers of the deltoid muscle), although when facing forward, they are the most lateral part of the deltoid. These fibers abduct the humerus by raising the humerus away from the side of the body.2, 3
The supraspinatus is a rotator cuff muscle that is also activated by seated lateral raises. It begins near the cervical (neck) vertebrae and anchors to the head of the humerus. Like the medial fibers in the lateral deltoid, the supraspinatus abducts the humerus. It also holds the head of the humerus in the shoulder joint, especially on any pressing movements.2,5
The shoulder joint is not very stable,1 so lifting massive weights (especially overhead) increases the potential for injury. This does not mean that you should not train your shoulders with decent loads, or totally avoid lifting overhead. Unless you are working toward “Strongman” competitions, you should reserve the super heavy stuff for squats and deadlifts. Seated dumbbell side laterals provide superb stimulation for the lateral deltoid without the need for hoisting super-heavy weights or risking injury to the rotator cuff muscles.6,7
THE EXERCISE: SEATED DUMBBELL LATERAL RAISE
1. Sit a short-backed, 90-degree bench and take a dumbbell in each hand with a neutral grip (turn the palms toward the side of the thighs).
2. Keep a slight bend in your elbows throughout the movement. This bend should not change during the exercise. Lean slightly forward to emphasize the lateral deltoid, but keep your head up.
3. Raise both dumbbells from a position starting adjacent to your lateral thighs and continue lifting upwards until the hands are at the level of the ears. Both arms should work at the same time. At the top position, you should be able to draw a line that runs from one dumbbell through your ears to the other dumbbell (i.e. do not let the hands drift forward). The palms should be facing the floor as you are lifting the weight upward. If you lift your hands higher than ear level, your upper trapezius muscle will do the work and this will not help develop the deltoid muscles any further.
4. If you want to put a little more fire in your shoulders, as you approach the top position you can begin to pronate the hands so that the knuckle of the little finger is at about a 45-degree angle, relative to the ceiling (like pouring a cup of water). Hold the top position briefly.
5. Maintain the same arc as you return your arms to the starting position. This means that you will turn the palms back to a position that is facing the floor, then lower your arms towards your thighs.
6. Do not pause at the bottom, but immediately begin the lift upward. This will keep the fibers in the deltoid firing throughout the set.
If you choose to add the rotation in the lift, make certain that you rotate at your shoulder joint (not just at the wrist) to make the knuckle of the little finger move upward as you approach the top of the lift. It is also important that you do the exercise strictly, without jerky movements. Finally, do not worry about using the largest dumbbell on the rack for this exercise. On the other hand, you cannot expect good results if you are lifting pencil weights or just going through the motions either.
- Reinold MM, Macrina LC, Wilk KE, Fleisig GS, Dun S, Barrentine SW, Ellerbusch MT, Andrews JR. Electromyographic analysis of the supraspinatus and deltoid muscles during 3 common rehabilitation exercises. J Athl Train 2007;42:464-469.
- Moore K.L., A.F. Dalley; Clinically oriented Anatomy. Fourth Edition. Baltimore, Lippincott Williams & Williams, Kelly, P.J. Editor, 1992;690-698.
- Yasojima T, Kizuka T, Noguchi H, Shiraki H, Mukai N, Miyanaga Y. Differences in EMG activity in scapular plane abduction under variable arm positions and loading conditions. Med Sci Sports Exerc 2008;40:716-72.
- Jakobsen MD, Sundstrup E, Andersen CH, Zebis MK, Mortensen P, Andersen LL. Evaluation of muscle activity during a standardized shoulder resistance training bout in novice individuals. J Strength Cond Res, 2012; electronically published ahead of print, PMID: 22067242
- Wickham J, Pizzari T, Stansfeld K, Burnside A, Watson L. Quantifying “normal” shoulder muscle activity during abduction. J Electromyogr Kinesiol 2010; 20:212-22.
- Youdas JW, Arend DB, Exstrom JM, Helmus TJ, Rozeboom JD, Hollman JH. Comparison of Muscle Activation Levels During Arm Abduction in the Plane of the Scapula vs. Proprioceptive Neuromuscular Facilitation Upper Extremity Patterns. J Strength Cond Res 2012;26:1058-1065.
- Kibler WB, Sciascia AD, Uhl TL, Tambay N, Cunningham T. Electromyographic analysis of specific exercises for scapular control in early phases of shoulder rehabilitation. Am J Sports Med 2008;36:1789-1798.