Build Your Anterior Deltoids

With Incline Bench Barbell Front Raises  

By Stephen E. Alway, Ph.D., FACSM

The shoulder has been designed for maximum mobility, but it provides very little in the way of stability. To make things even more problematic, it is a poor mechanical lever, so that tremendous amounts of force have to be generated even before the smallest of weights can be lifted. For example, raising a light 10-pound dumbbell to the front with a straight arm requires more than 250 pounds of force at the shoulder joint. While this type of effort and more is required, you want to amplify your shoulder strength and add muscle mass to your shoulders (deltoid muscle), and specifically the anterior part of your deltoid, and you also have to pay attention to exercise form to protect your shoulder against injury.

The incline bench front barbell shoulder raise provides an outstanding opportunity to hit the anterior deltoid, and to a lesser extent the medial deltoid in a direct fashion. The trajectory of the arm movement in incline bench front barbell raises requires shoulder flexion, which is the job of the anterior fibers of the anterior deltoid muscle.1,2 The deltoid muscle is secured at three primary regions.2,3 The anterior fibers of the deltoid are anchored along the lateral part of the clavicle (collar bone). The medial fibers of the deltoid originate from regions between the anterior and posterior deltoid, along the acromion of the scapula (the point of the shoulder). The posterior fibers attach along the spine of the scapula (shoulder blade), which is on the upper and posterior side of the scapula.2 The fibers of the deltoid converge together on the anterior and upper portion of the humerus bone.2,3

The anterior fibers of the deltoid produce strong flexion of the humerus at the shoulder (bringing the humerus bone of the upper arm forward),1 and also medial rotation of the humerus at the shoulder.3 It is these fibers that are primarily activated by incline bench front barbell shoulder raises. The medial fibers abduct the humerus bone of the arm (raise the arm away from the side of the body).3 However, they also support the humerus during the lift upwards.1Thus, the medial region of the deltoid will be activated during incline bench front barbell shoulder raises, but not to the same degree that the anterior fibers are recruited. The posterior fibers produce strong extension (bringing the humerus bone posteriorly) of the humerus and consequently they are not activated by the forward raises in this exercise.

The supraspinatus muscle is one of the rather delicate rotator cuff muscles3 of the shoulder. The supraspinatus is a rounded muscle that lies deep to the trapezius muscle in the supraspinatus fossa. This fossa (hollowed out area in the bone) is located on the top part of the posterior side of the scapula bone. The supraspinatus muscle begins near the medial side of the scapula (close to the vertebrae and the center of the body) and runs to the superior part of the head of the humerus bone of the upper arm.2 This muscle assists the anterior deltoid to lift the barbell upwards.4,5 However, the degree of activation and stress is markedly lower than exercises like overhead presses, which really taxes the supraspinatus muscle.

Incline bench front barbell shoulder raise

1. Lie face down with your head and shoulders hanging over the top of an incline bench. Take a shoulder-width (or a little narrower) pronated grip (palms facing down) on a light barbell. You will probably need a partner to lift the bar in place for you while you are on the bench.

2. Your arms will be hanging straight down towards the floor in the starting position. Slowly lift the barbell from this position and pull it up to the level of your shoulder joints. This should be at a level that is at or just a little above a position in which the forearms and upper arms are at eye level. Keep your elbows locked throughout the lift. Take one to two seconds for the lift upwards.

3. Return the barbell slowly (take about 3 seconds) to the starting position. Do not let the barbell swing past a position where the arms are perpendicular to the floor, otherwise the next upward lift will likely be helped by the pendulum-like momentum rather than muscle force.6

4. Immediately start the next upward lift and repeat until your set is done.

Moving the barbell upwards activates the anterior and medial fibers of the deltoid6,7 and the supraspinatus muscle of the rotator cuff.5 However, if you raise your arms much above a position that is at eye level, you recruit your upper trapezius muscles and serratus anterior muscles1,3,4 rather than more completely activating your deltoid muscle. Thus, if your primary objective is to add strength and mass to the anterior deltoids, then raising the bar to the top of your head is unnecessary.

If the bulk of your shoulder training consists of heavy overhead lifts, you will develop strong and thick muscles, but this increases the risk for joint injury. While this is not inherently bad, you need to evaluate whether the shoulder risk associated with lifting heavy weights is consistent with your sport and health goals. For most people, incline bench barbell shoulder raises will provide superior isolation of the anterior (and somewhat medial) deltoid without excessive stress to the shoulder joint. This exercise is so effective because it isolates the deltoid muscle fibers, hitting these fibers directly and powerfully with a sustained contraction throughout each repetition. As a result, you can get great results without needing to lift the super human stuff. The delicacy of the shoulder joint means that you need to approach this region with cautious intensity, rather than reckless abandon. Thus, if you want to inject new strength into your shoulders, find an empty incline bench and lift away, knowing that your deltoid is about to “massify” without undue joint stress.

References:

1. Wattanaprakornkul D, Halaki M, Boettcher C et al: A comprehensive analysis of muscle recruitment patterns during shoulder flexion: an electromyographic study. Clin Anat 2011;24:619-626.

2. Moser T, Lecours J, Michaud J et al: The deltoid, a forgotten muscle of the shoulder. Skeletal Radiol 2013;42:1361-1375.

3. Moore, K.L. and A.F. Dalley. Clinically oriented Anatomy. Fourth edition. Baltimore, Lippincott Williams & Williams,1999; 685-720.

4. Escamilla RF, Yamashiro K, Paulos L et al: Shoulder muscle activity and function in common shoulder rehabilitation exercises. Sports Med 2009;39:663-685.

5. Wattanaprakornkul D, Cathers I, Halaki M et al: The rotator cuff muscles have a direction specific recruitment pattern during shoulder flexion and extension exercises. J Sci Med Sport 2011;14:376-382.

6. Arandjelovic O: Does cheating pay: the role of externally supplied momentum on muscular force in resistance exercise. Eur J Appl Physiol 2013;113:135-145.

7. Schwartz DG, Kang SH, Lynch TS et al: The anterior deltoid’s importance in reverse shoulder arthroplasty: a cadaveric biomechanical study. J Shoulder Elbow Surg 2013;22:357-364.

Illustrations by William P. Hamilton, CMI

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