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Safeguarding Shoulder Health

The human body is nature’s most sophisticated piece of machinery. Let’s briefly analyze one its most fundamental tasks: movement. Movement is the resultant cascade of neurophysiological functions beginning with the beaconing of efferent signals from the central nervous system to the pools of motor units innervating skeletal muscle. The recruitment of motor units is dependent upon the task and associated external force needed to meet said task. The rate and selectivity at which motor units are recruited are influenced by an individual’s neural efficiency. The magnitude and rapidity of force production exhibited during activities of daily living, recreation, and competition are largely improved through resistance training.

It can be deduced from above that strength training can finetune our body, particularly its neuromuscular system — a system comprised of a web of trillions of nerves, hundreds of millions of muscle fibers composing 656 muscles that govern the movement of, attach to, and stabilize 206 bones.

A constellation of those bones intersects in the shoulder area — one of the most tightly packed and intricate area within the entire body. Those bones, the scapula, or shoulder blade, clavicle, or collarbone, and humerus, or arm bone, are linked by a swath of muscles and tendons that not only confer stability, but act in concert to produce, dissipate, and transfer forces.

The shoulder area can be regionalized into four joints — all interdependent due to said forces that are transmitted through the area during activities of daily living, recreation, and competition.

  • Glenohumeral (GH) joint
  • Scapulothoracic (ST) joint
  • Acromioclavicular (AC) joint
  • Sternoclavicular (SC) joint

The GH joint is a synovial ball-and-socket joint and is considered a diarthrodial, multiaxial joint as moves freely in multiple planes. The GH joint can move in the sagittal plane by extending (via the activation of the latissimus dorsi, posterior deltoid, and to a lesser degree, the long head of the triceps) and flexing (via the activation of the pectoralis major and anterior deltoid), in the frontal plane by abducting (via the lateral deltoid, commonly referred to as the “medial” deltoid) and adducting (via the pectoralis major and latissimus dorsi) and transversely, by internally and externally rotating the shoulder, finer movements which are governed by the rotator cuff muscles.

The rotator cuff muscles are comprised of two muscles that assist with external rotation of the humerus — infraspinatus and supraspinatus — and two muscles that assist with internal rotation of the humerus — the subscapularis and teres minor.

Fibers of the infraspinatus originate below the spine of the scapula and blend into the middle facet of the head of the humerus also known as the humeral head. Fibers of the supraspinatus originate below the spine of the scapula and blend into the superior facet of the humeral head.

Fibers of the subscapularis emanate from the costal concavity or deep side of the scapula and insert into the lesser tubercle of the humeral head. Fibers of the teres minor emanate from the lateral edge of the scapulae and insert into the inferior facet of the humeral head.

These four muscles literally serve as the musculotendinous linkage between the scapula and humerus and work in accord to actively stabilize the humeral head, so it remains seated within the glenoid fossa — the shallow enclaves on the medial edge of the scapulae.

The positioning and movement of the scapulae is governed by a deep roster of muscles — (17) muscles share connections to its bony parcels. The scapulae and the region of the thoracic spine they flank comprise the scapulothoracic or ST joint.

The ST joint permits great ranges of movement. The thoracic spine twists transversely, extends, flexes, and bends laterally, both left and right while the scapulae are intended to glide freely atop the posterior ribcage.

The scapulae can elevate or “shrug” (via the activation of the upper trapezius), upwardly rotate (via the activation of the lower trapezius), protract (via the serratus anterior), retract (via the rhomboids with the assistance of the middle trapezius), downwardly rotate (via the rhomboids, again) and depress (via the latissimus dorsi with contributions from the pectoralis major and minor muscles). The muscles collectively cocooning the scapulae share force couples which are defined as a relationship shared by two or more muscles on opposing sides of a joint working together to stabilize or create movement. Force couple disruptions at the scapulae are common and result in scapular dyskinesis marked by aberrant scapular tracking leading to downstream effects on upper extremity function.

For instance, if the scapulae are skewed into a protracted position, shoulder impingement accompanied by decrements in strength may arise. Another example of altered scapular positioning is scapular winging which stems from a faulty force couple of the serratus anterior, pectoralis minor, and rhomboids that heavily taxes the shoulder and elbow joints during activities of daily living.

The positioning and functions of the acromioclavicular or AC joint and the sternoclavicular or SC joint can be impacted by the positioning of the scapulae. The function of the AC joint is to “pull” the scapulae, helping it glide upwards during overhead movements. If the scapulae are locked into a poor position, the ligaments of the AC joints can wear down over time and lead to instability sometimes accompanied by anterior shoulder pain. Through the positioning of the clavicles, which abut the scapulae, the SC joint exerts a counterbalancing action on the scapula — providing stability during upward rotation and “pulling” of the AC joint.

Fortunately, fitness professionals can incorporate some measures within their client’s programming to mitigate injury risk without adversely impacting performance or enjoyability of training.

  1. “Undo” bad static posture.

Recent research points to an increase in back and neck pain among remote employees — this is likely attributable to increased screen time and a bleed of working hours into leisure activities and otherwise off time. If one is perpetually slumped in a kyphotic position with forward head posture, it is highly recommended these postures be “undone” through training.

Thoracic Spine Extension and Rotation

  • Thoracic Extension Over Foam Roller
  • Torso Supported Thoracic Extension with Extended Arms
  • Thoracic Extension Against Wall with Shoulder Flexion
  • Quadruped Thoracic Rotation (with or without reach)

Scapular Rotation, Stabilization, and Protraction

  • Prone Trap Raise (bent, torso supported, quadruped — performed unilaterally)
  • Forearm Wall Slides
  • Scapular Wall Slides
  • Lat Pulldown Isometric Hold
  • Push-up Plus

Rotator Cuff Muscle Activation Exercises

  • Three Way Dumbbell Drops
  • Incline Side Lying Raise
  • Bottoms Up Plate Press
  1. “Keep it closed” for a little while.

If possible, substitute open kinetic chained exercises with closed kinetic chained exercises. Open kinetic chained exercises are characterized by the proximal segment (i.e., the torso) in a fixed position while the distal segments (i.e., hands) move. Examples of open kinetic chained exercises would be a bench press among any other pressing exercise in which the torso is supported. When the torso, specifically the dorsal or back side is supported, scapular tracking is inhibited. The scapulae will not be able to rotate sufficiently upwardly, thereby taxing the shoulders as they repeatedly move overhead during pressing movements. Conversely, closed kinetic chain exercises enable more natural scapular tracking as distal segments (i.e., hands) remain fixed on the ground or another stable surface to facilitate the movement of the proximal segment (i.e., the torso).

  1. Re-evaluate and refine your overhead pressing.

First, determine if overhead pressing is necessary or perhaps contraindicated for your clients. If they do not have an injury history or anthropometric limitations (i.e. have a hooked or upturned acromion process which will cause functional shoulder impingement) and are no averse to performing overhead pressing, proceed.

But if you want to reduce injury risk, consider employing the following exercise hacks.

  • If possible, encourage overhead pressing without a seat back, since that could potentially interfere with scapular tracking. Though external load may be sacrificed, this is of lesser importance among clients who are not training for limit strength. And the overhead press from a standing position has far more carryover to activities of daily living and recreational competitive sports.
  • When overhead pressing with the barbell, use a biacromial or shoulder width grip. Though wider hand placements can reduce the range of motion thereby permitting greater external loads, they can expose the anterior shoulder to undue stress since it is nearly in full external rotation and abduction.
  • If overhead pressing with dumbbells, consider incorporating a neutral grip or one in which the palm sides of the hands face each other. Doing so will help prevent the shoulders from jutting too far into external rotation and abduction under load.

Want More… Check out a new webinar on the topic this year too.

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