Overhead Shoulder Mobility Part 1 – Anatomy & Kinematics [Clinicians & Trainers]

Do your clients have trouble getting their arm overhead during the barbell press? Rounded upper backs causing them to have a blocking feeling or pain? They can’t move the barbell overhead without arching their low back?

Well, you’re not alone. These are some common issues that occur when clients attempt to perform an overhead press- a movement that looks simple but requires intricate coordination between several different regions of the upper body.

This blog series will be broken down into 3 individual parts that when put together will help you to understand what is required for overhead motion, how to determine where your restriction is, and how to fix it.

Overhead Mobility Breakdown

–         Part 1: Anatomy & kinematics

–         Part 2: Assessment

–         Part 3: Drills & fixes

What follows here is a very basic anatomical and kinematic breakdown of overhead motion meant primarily for clinicians/trainers or anyone with a keen interest in kinematics meant to help you see the vast amount of moving parts required for overhead mobility.

The first thing we need to understand when considering overhead mobility is that we cannot visualize the motion of the arm in isolation. The arm (humerus) articulates with the shoulder blade (scapula) forming the glenohumeral joint. Coupled motion occurs at this joint between the humerus and scapula during arm elevation, and is termed scapulohumeral rhythm. This rhythm is necessary for proper glenohumeral joint alignment and maximal stability. Frequently in the literature a 2:1 relationship between the GH joint elevation and upward rotation is cited though as you’ll see below it is significantly more complicated than that1. The scapula itself moves along the thorax free of bony articulations, this joint is termed the scapulothoracic joint. Without adequate motion and stability at this region, our glenohumeral joint will often experience dysfunction. Even the tiny clavicle plays a role in overhead motion of the arm. Despite all those moving parts it gets even more complex when we consider that the T-Spine, just like in the squat, has a component in overhead mobility. So essentially motion of the arm overhead requires proper functioning at each of these regions:

• Thoracic Spine
• Scapulothoracic Joint
• Sternoclavicular & Acromioclavicular Joints
• Glenohumeral Joint
• Motor Control (not covered here)

Our discussion will start most proximally with the role of the T-Spine

What we should see at your t-spine during elevation:

–    T-spine extension: ~ 10.5 – 12.8 degrees should occur in arm elevation.

–    The main region of t-spine extension comes from the lower t-spine which contributes ~ 7 – 8 degrees, while the upper t-spine additionally provides ~ 3 – 4 degrees3.

• Normal t-spine kyphosis (rounding of a spinal section) = 26 degrees2
• Greater extremes of kyphosis or lordosis of the t-spine can cause instability of the scapula on the thoracic cage, translating into overhead mobility issues.

The second component and possibly the most complex to understand is the role of the Scapula   

What we should see at your scapula during elevation:

–     Upward rotation: at least 45 – 55 degrees in frontal plane

–     Posterior tilt: 20 to 40 degrees in the sagittal plane

–     External rotation: 15 to 35 degrees in the transverse plane6

 Scapulothoracic articulation

• Scapula articulates with the thorax, though there is no direct bony articulation.
• Function of the scapula include elevation/depression, upward/downward rotation, internal/external rotation, and anterior/posterior tilt1.
• Provides a stable base of support for the GH joint to fixate and function from.
• Several force couples acting on the scapula are necessary for proper movement of the joint along the thorax.
• The scapula has minimal motion during the first 30 degrees of humeral elevation, but incrementally increases as the angle of elevation increases7.
• Elevation in different degrees between the frontal and sagittal planes will also influence the degree of scapulohumeral rhythm with less motion occurring from the scapula as we approach the sagittal plane.
• Typically, around 60 degrees of upward rotation occurs in conjunction with arm elevation.

Muscular considerations on scapula kinematics:

• Serratus anterior – functions to protract, upwardly rotate, externally rotate, and posteriorly tilt the scapula as well as stabilize the medial border and inferior angle.Middle and lower serratus functions more efficiently than the upper serratus in these functions due to line of pull.
• Upper trapezius – functions to elevate and upwardly rotate the scapula.
• Middle trapezius – functions to retract and stabilize the humerus.
• Lower trapezius – functions to depress, posteriorly tilt, external rotation, and upwardly rotate the scapula.Upward rotation from the lower trapezius typically occurs after 90 degrees of elevation and after the initial 30 degrees of upward scapula rotation.
• Rhomboids & levator scapulae – function as downward rotators primarily, but also have a synergistic role to resist lateral translation of the scapula caused by the serratus4.

 The third component is the Sternoclavicular & Acromioclavicular Joints

What we should see at the clavicle during elevation:

–    Sternoclavicular joint – slight elevation, retraction, and posterior rotation

–   Acromioclavicular joint – upward rotation, internal rotation, and posterior tilt

• The initial 30 degrees of clavicular elevation depends on a smooth first 30 degrees of upward rotation of the scapula.
• Following that point limitation by the costoclavicular and coracoclavicular ligaments will act as a force couple causing posterior rotation of the clavicle which then allows for further elevation.
• This additional clavicular elevation helps the scapula to achieve its full range of upward rotation5.

The final component is the Glenohumeral Joint

What we should see at the glenohumeral joint during arm elevation:

–    Glenohumeral joint: displays ~ 120 degrees of arm elevation in conjunction with the ~ 60 degrees of upward rotation giving us a full 180 degrees of arm elevation.

• External rotation caused by action of the infraspinatus and teres minor is also necessary to allow the arm to elevate past 90 degrees without abutment of the greater tubercle on the coracoacromial arch.

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Muscle consideration on glenohumeral joint stability/motion:

• At the glenohumeral joint, the deltoid is the prime mover of the arm into humeral elevation, assisted by the supraspinatus as an accessory elevator.
• The rotator cuff functions to stabilize the humeral head through a medially directed compression force into the glenoid fossa.
• The subscapularis, infraspinatus and teres minor also have an inferior directed line of action, which allows activation of these muscles to offset the superior translation component of deltoid muscle action6.

Check out our past blogs if you’ve liked what you’ve read!

• Squat Assessment Blog
• Post Activation Potentiation Blog
• Chronic Low Back Pain Blog

1. Paine R. (2013) The Role of the Scapula. International Journal of Sports Physical Therapy. 8(5): 617 – 629.
2. McKean M, Burkett B. (2013) Overhead Shoulder Press – In-front of the head or behind the head? Journal of Sport and Health Science. 4: 250 – 257.
3. Edmondston S, Ferguson A, Ipperseil P, et al. (2012) Clinical and Radiological Investigation of Thoracic Spine Extension Motion During Bilateral Arm Elevation. Journal of Orthopedic and Sports Physical Therapy. 42(10): 861 – 869.
4. Phadke V, Camargo P, Ludewig P. (2009) Scapular and Rotator Cuff Muscle Activity During Arm Elevation: A Review of Normal Function and Alterations with Shoulder Impingement. Rev Bras Fisioter. 13(1): 1 – 9.
5. Schenkman M, Cartaya V. (1987) Kinesiology of the Shoulder Complex. The Journal of Orthopedic and Sports Physical Therapy. 8(9): 438 – 450.
6. Reinold M, Escamilla R, Wilk K. (2009) Current Concepts in the Scientific and Clinical Rationale Behind Exercises for Glenohumeral and Scapulothoracic Musculature. The Journal of Orthopedic and Sports Physical Therapy. 39(2): 105 – 117.
7. Scibek J, Carcia C. (2012) Assessment of Scapulohumeral Rhythm for Scapular Plane Shoulder Elevation Using a Modified Digital Inclinometer. World Journal of Orthopedics. 3(6): 87 – 94.