Note:The exercises below are instructional only and are not meant to be part of a treatment program. If you are having pain, do not perform the exercises below. Please see a physician or CALL ME for a brief discovery session to determine the best course of action
Glenohumeral joint: The glenohumeral joint (shoulder) is the most mobile joint in the body and is the meeting of the humerus & scapula. GLENO-is short for Glenoid Fossa, which is the concave portion of bone the head of the humerus sits in.
Scapulothoracic joint: “pseudo” joint or physiologic joint, between scapula & wall of thorax.
With all overhead CrossFit lifts, the body performs a balancing act, preventing shoulder dislocation by stabilizing the joint (holding the bones in place), yet also allows for significant movement.
Scapulohumeral Rhythm: This is described as contributions made by multiple joints (Glenohumeral joint & Scapulothoracic joint) to create overhead shoulder movement. In addition to the scapulohumeral joints, the joints of the clavical (Acromioclavicular & Sternoclavicular joints) provide stability, preventing the scapulae from drifting too far forward, and anchor the scapula in place during arm elevation.
Proper strength, mobility, and timing of muscular contractions are required to lift weight overhead.
Dysfunctional scapular movement, or “Scapular Dyskinesis” may lead to:
Less Force Output: Inability to create explosive force
Plateau: Because muscular imbalances may impair scapular movement, this can lead to a strength plateau. To put it simply, it’s easier to lift furniture with two movers instead of just one. Under-utilizing a muscle group is like using one less mover. The plateau occurs when the primary mover is unable to exert more force and the body is unable to “recruit” more muscle fibers/groups to complete the lift.
Injury: Scapular dyskinesis may place increased compressive forces on the supraspinatus. This is one of four rotator cuff muscles that allows us to lift our arm up at the side of the body (abduction, or the position of the arm during a jumping jack). Rotator cuff compression may lead to degeneration, tearing, rupture, or chronic pain.
Shoulder instability: Scapular internal rotation (the inside border of the scapula is raised) may lead to gapping over the front of the shoulder between the humeral head and glenoid, which may lead to altered mechanics and instability.
Summary Thus Far: Your shoulder (glenohumeral joint) has the most range of motion of any other single joint in the body and thus requires more stabilization. The joints and muscles around your shoulder work together to make this happen. If some muscles are weaker than others or you’ve had past shoulder injuries, you may have dysfunctional shoulder blade movement (scapular dyskinesis). This may also be due to neural changes in the brain, which would result in inefficient movement patterns. These scapular movements can create weaknesses that are difficult to locate without specific tests/measures, instability, muscular plateaus, or injury.
Force couples occur throughout the body with both simple and complex movement. A FORCE COUPLE is a group of muscles around a joint, that either produce movement or stabilize a joint.
An excellent example of a force couple are the muscles of the scapula, which work together to let you reach or lift overhead. Scapular upward rotation is the rotation of the shoulder blade as you lift your arms overhead.
Scapular upward rotation is initiated by the Serratus Anterior (SA), which starts from the outside of the lower ribs, and inserts into the underside of the scapula (the side closer to the ribs). When the SA contracts it initiates upward rotation. Upward rotation has a few purposes. It helps the muscle maintain a length-tension relationship to generate a maximum amount of force.
An example of this is bending your elbow. It’s much harder to generate force if the arm is fully straight as opposed to slightly bent. This is because the muscle length is in an optimal position for contraction in a neutral position. Upward rotation also helps maintain the surface of the glenoid fossa with the humeral head (preventing subluxation).
The upper trap kicks on after about 45 deg, and the lower trap assists last with overhead movement.
It has been shown that individuals who have chronic shoulder pain tend to have LESS serratus anterior strength, altered muscle firing, and over-utilize the upper trap and levator scap (another muscle close to the upper trap that both raises the scapula and creates downward rotation, OPPOSING the movement in question). This antagonistic compensation may lead to upper trap & levator scap fatigue, as they are playing “tug-of-war” at the top of the scapula.
Muscular strengthening & isolating muscles
Research has shown that applying 40% max resistance to an isolated muscle will fatigue the muscle quicker, and promote more specific muscle strengthening than a Max lift for a group of muscles. Surgeons use scalpels, not hammers for precision. Strengthening exercises targeting specific muscles should focus on very specific movements (based on the action of the muscle), and utilize less resistance to avoid compensatory patterning from surrounding muscles.
What does this mean for CrossFitters?
This information is not helpful if it doesn’t help you reach realistic goals. The important thing to take from this is that heavier is not necessarily better in all situations. Max lifts may not break through a plateau if the muscles doing the job overshadow muscles that are either weak or not engaging properly (because of poor neuromotor control/muscle mapping).
Know your weaknesses and make them strengths. This ideology will help you overcome plateaus, create a roadmap for success, and prevent future injury. Truly understanding weak areas of the shoulder girdle may require more than a look at your form. An in-depth performance & strength assessment by a Doctor of Physical Therapy or other high level athletic professional may be the way to do this. Aside from electromyographic diagnostics, this will be the best you have. See below for my details on getting an assessment at my clinic or click HERE to schedule a performance assessment
Medial Border Dysfunction
The scapula is internally rotated in a resting position. This is also called scapular “winging”. May be due to weak or partial paralysis of the Serratus Anterior (usually weakness). This position of the scapula may lead to shoulder instability.
This is anterior tilting of the scapula (tipping forward). This scapular position lengthens the lever arm of serratus which may reduce scapular force production (affects length/tension relationship). It also compresses the supraspinatus tendon which may lead to rotator cuff pain or injury.
Serratus Anterior exercises: The exercises below have been shown through clinical research to promote the greatest percentage of SA firing in isolation, with limited Upper Trapezius firing which is typical.
May perform @ 40% Max Strength, avoid shrugging shoulders, avoid moving elbows from sides
Band External Rotation with Scapular Retraction Hold
Place your elbows bent 90 degrees at your sides, with a stretchy band in your hands (thumbs up). While keeping your elbows in place, pull the band,
rotating your arms backwards to about 45 deg. In this position, pull your shoulder blades together and hold about 5 seconds. Repeat this.
Push-Up Plus (Scap pushups)
Assume pushup position, while maintaining straight elbows. Shrug your shoulder blades together and slowly relax, moving your body with your shoulders (keep elbows in same extended position). Focus specifically on the movement of lowering your body towards the floor.
This exercise is advanced, and you may begin with wall Push-up Plus in needed.
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