2014-03-28



Your shoulders serve a lot of purposes during daily life and are used during virtually all upper-body movements. Made up of an intricate web of ligaments and tendinous tissue (muscle attachments), the glenohumeral joint (GH) offers the upper body a very mobile joint that is called upon during sports, active play and exercise. But, like a double-edged sword, the maneuverability of the GH joint enables the body to complete numerous tasks and also makes it susceptible to chronic and acute injury.

This maneuverability is aided by the congruent effort of the scapula. The scapula is considered the “anchor” of the shoulder. The scapula houses the attachments of the four rotator cuff muscles (supraspinatus, infraspinatus, teres minor and subscapularis). These four muscles arise from the scapula and attach into the top (head) of the humerus (upper arm bone). During movements, the rotator cuff compresses the GH joint in order to bring the arm up and out. Without proper conditioning and function of the rotator cuff muscles, the humeral head would partially ride up inside the joint, lessening the efficiency of the deltoid muscle and potentially causing injury by virtue of compressing the tendons of the rotator cuff against the acromioclavicular joint. [1]

The Keys to Protecting Your Shoulders

In order to add miles to your upper body regimen, we have to examine a few key components to understand how to make a strategy to protect the shoulder joint:

Joint Stability

As the scapula serves as the “anchor” of the shoulder, it should be strong enough to stabilize the joint in order for the four rotator cuff muscles stabilize the humerus. Although all the rotator cuff muscles play a specific role of stabilizing the scapula during certain movements, the serratus anterior and pec minor also play important roles. Liken the role of the scapula stabilizers as a taut fishing line. As the fisherman reels his catch, the taut fishing line allows him to pull (create force) through the pole on each pull. If the line is not rigid and becomes droopy, the fisherman will possibly break the line on his next pull [of the fishing pole]. Strengthening the serretaus anterior and rotator cuff muscles to collectively stabilize when needed is crucial to shoulder health.

Joint Mobility

Just as the muscles that comprise the GH joint and scapula must be able to stabilize, they must also be capable of completing a desired movement without restriction. Capsular tightness, muscular stiffness, adhesions, and joint pain will restrict mobility at a specific joint. Past injuries that create faulty neurological patterns will also cause limited mobility. Without exercising proper joint mobility, we will severely handicap by the next component: flexibility.

Flexibility

Although the shoulder joint is considered highly mobile, muscle tightness can still limit its range of motion. Unlike mobility, which is centered to the structure of the joint, flexibility involves the length-tension of the muscles crossing the joint. In order to maintain flexibility at the shoulder, concentrating on the muscle’s length around the joint structure is vital. In this case, muscle length-tension should be balanced throughout; and maintained frequently with regular stretching. The more sedentary an individual is the more flexibility becomes an important component. Conversely, the more one lifts intensely, the more flexibility is vital to joint health.

Core Activation/Stiffness

What does the rest of the body do during overhead activity? More importantly, how does the rest of the body respond to LOADED overhead activity? Pairing core activation and stiffness may sound like a misnomer, but in actuality, when the core is properly activated, it “stiffens” to protect the spine and allow the muscular system to produce force safely and effectively. It does this by virtue of abdominal bracing. Once the intrinsic abdominal musculature is “braced” or stiffened, it stabilizes the spinal column via the pelvic girdle and entire torso. This stabilization allows the shoulders-particularly the scapula-to create stiffness so that the rotator cuff muscles can dynamically “hold” the humerus in place during overhead activity. The rest of the body becomes a rigid lever for the working muscles to produce force from. This phenomenal system of creating force couples in an intricate web of muscles and tissue allows joints to operate in an optimal fashion. When joints can work optimally, the body can accept challenges (load), in an environment that significantly reduces the likelihood of injury. Imagine having 5 wooden blocks stacked on top of one another. If you apply pressure to the two outside blocks with your fingers, the middle blocks stay positioned in place. Now try turning the middle block with your other hand. The harder you squeeze the outer blocks inwards, the more difficult it becomes to turn the middle one. If less pressure is applied, it allows the middle blocks to turn easier and possibly fall. The middle block succumbs to the force applied to its surrounding structures. This is how the core of the works by “stiffening”. In essence, when the core works effectively during activity, the body becomes a well-oiled machine.

Grip Position

Objects, particularly barbells and dumbbells, can be held in one of three positions: supinated, pronated, or neutral. Studies have shown that supinated and neural grip positions are stronger than the pronated position. This will prove valuable to long-term shoulder health because the position of the wrist during gripping directly relates how the tip of the humerus positions itself within the glenoid fossa. The glenoid fossa is the boney structure that houses the GH joint and resembles the flat top of a golf tee. Concave in design, the glenoid fossa allows the humeral head to move smoothly with the help of the rotator cuff muscles. The grip used during overhead loaded activity dictates how much room the humeral head and surrounding tendons have under the acromioclavicular (AC) joint. When the wrist is positioned neutrally, the lower arm corresponds to external rotation of the humerus, which makes more room under the subacromion space. [2]

Strength

In the end, strength at each joint is what makes all possible. When one is strong, all components work collaborately to enhance performance. Strong musculature around a joint enables the process of creating rigid levers, stabilization, and force production to occur under proper activation of the core and length tension relationships. When one is strong, challenging exercises become easier and easier to achieve.

The Factors that Affect Shoulder Health

To understand the factors that affect shoulder health, we should categorize the common risks typically seen in individuals that run the risk of shoulder injury.

 Desk WorkerAverage LifterAthleteLacks Joint StabilityYesMaybeNoLacks Joint MobilityYesYesMaybeLacks FlexibilityYesMaybeMaybeLacks Core ActivationYesMaybeNoLacks Optimal Grip PositionMaybeMaybeMaybeWhy do these factors cause these problems?

 Desk WorkerAverage LifterAthleteJoint StabilityProlonged sitting increases likelihood of poor posture: protracted shoulders, upper-cross syndrome, excessive cervical flexionSome strength may correct length-tension relationships; however more prone to imbalance (push to pull ratio)Instructed correctly, joint structures operate optimally to prevent injuries and allow proper movement patternsJoint MobilityProlonged seated positions increase joint stiffnessLifters lack joint mobility drills and proper warm-upsSome athletes focus on joint mobility drills, however some may be neglected, particularly the thoracic spineFlexibilityProlonged seated causes passive fatigue which shortens musclesLifters “skip” stretching and create muscular imbalances from excessive pattern similaritiesAthletes know the importance of flexibility and stretch regularlyCore ActivationProlonged sitting utilizes no core activation, especially when fatiguedLifters may know how to activate or brace the core in isolation, but may fail to do so during heavy liftingAthletes are more in-tune with core activation when lifting; however, some do miss bracing at times.Grip PositionOffice materials call for different hand positions; ergonomics and movement imperativePronated grip from excessive overhead pressing and bench pressing may cause wear in unhealthy shouldersNeutral grip is easier on the shoulder joint; perform proper movements and a decent mix of grip positions for exercisesLike a construction company erecting a building, we can’t look at the shoulders alone. We have to look at the foundation from which the shoulders will be constructed upon. In this case, we must address the core and overall static posture. If corrections and neurological adaptations are made to strengthen postural distortions, the body will become more proficient producing force under loads (exercise).

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