The Shoulder in the Kinetic Chain

The shoulder complex functions as part of a kinetic chain, which is defined as a series of links and segments activated sequentially in a coordinated fashion to generate and transmit forces to accomplish a specific function.^2,3 An example of a kinetic chain is the childhood game crack the whip, wherein a group of children hold hands in a line to try to accelerate the last child by creating a whip effect. Each child represents a segment of the chain and their joined hands represent links that sequentially create increased energy, force, and velocity. In activities that use a throwing motion (e.g., pitching or tennis), there is proximal to distal muscle activation and coordination of body segments producing interactive moments at the terminal segment (hand or racket).^4,5 The initiating ground reaction force is increased as it is transmitted through the knees and hips through the large muscles of the legs into the lumbopelvic region and the rest of the trunk. The proximal segments—that is, the legs and trunk—produce roughly half the energy (51%) and force (54%) that is ultimately delivered to the distal end of the kinetic chain.^6,7 The scapula and glenohumeral joint function as both a link and segment in the chain, increasing the kinetic energy and force generated, and as a conduit to funnel and transmit these forces to the distal segments.

When an individual reaches, pushes, or pulls from a sitting position, there is less energy and force contribution from the legs, and the primary generator for upper extremity motion is the initiation of trunk stabilization. Coordinated muscle activation sequences result in movement patterns, which create joint motions to efficiently accomplish specific tasks. These diagonal activation patterns create a “serape effect” from the knee or lumbopelvic region to the shoulder,⁸ act locally on one joint or harmonize several joints, provide cocontraction force couples that control joint perturbations and provide stability, and generate and transmit force. This allows the scapular stabilizing muscles to position the scapula optimally for shoulder function and for the rotator cuff to compress and position the humeral head in the glenoid fossa.

The Scapula in Shoulder Function

The scapula provides anatomic and kinematic connections between the torso and upper extremities. The shoulder muscles can be classified anatomically by their origins and insertions into the axioscapular, scapulohumeral, and axiohumeral group. The axioscapular muscles that attach the scapula to the thorax include the serratus anterior, trapezius, rhomboids, levator scapulae, and pectoralis minor. These scapular stabilizing muscles position the scapula optimally for the humeral head. The serratus anterior and trapezius muscles are so large that the muscle fibers course in different directions and, as a result, both muscles have multiple functions that relate to activity and arm position.⁹ The scapulohumeral group consists of the supraspinatus, infraspinatus, teres minor, subscapularis, deltoid, and teres major. The rotator cuff muscles provide concavity or compression at the glenohumeral joint and fine-tune humeral head rotation and depression in an attempt to keep the humeral head centered in the glenoid throughout the arc of upper extremity motion. The axiohumeral muscles, the pectoralis major and latissimus dorsi, are the considered the power muscles of the shoulder. Shortening or tightness of these muscles is frequently associated with abnormal glenohumeral kinematics. The biceps and triceps comprise a special category, because they extend from the scapula to the forearm.

The shoulder complex is an important kinematic link between the trunk and arm, providing a stable platform for arm rotation during throwing. The scapulothoracic articulation, and the glenohumeral, acromioclavicular, and sternoclavicular joints, form two individual but paired mechanisms, one an open chain and one a closed chain.¹⁰ A closed kinetic chain, such as the one formed by the thorax, scapula, and clavicle, is defined by the terminal link being fixed or immovable. The glenohumeral joint is an open kinetic chain mechanism, allowing movement of the hand as the terminal link. Normal shoulder function and scapulohumeral rhythm require that all four articulations participate in a simultaneous, synchronous, and coordinated manner, and that the muscles controlling them are activated in the correct succession.

Scapular motions include upward and downward rotation in the coronal plane about an anterior-posterior axis (Fig. 3-1A), anterior and posterior tilting in the sagittal plane about a medial-lateral axis (see Fig. 3-1B), and internal and external rotation in the transverse plane about a vertical axis (see Fig. 3-1C). In addition, there are translations of the clavicle and thus of the scapula, in the superior and inferior directions (scapular movement along the vertical axis), as well as in protraction and retraction or abduction and adduction (scapular movement along the medial-lateral axis). Several investigators have shown that during glenohumeral elevation, the normal scapula demonstrates upward rotation, external rotation, and posterior tilting and translates into a more superior and posterior position.^11,12

FIGURE 3-1 A-C, Scapula rotations.

The scapular stabilizing muscles function as force couples to control the motions of the scapula. A force couple is formed when two forces act in opposite directions to impose rotation about an axis. The serratus anterior controls the movements of internal rotation, upward rotation, anterior tilting, and lateral translation when it fires concentrically, and external rotation, downward rotation, and posterior tilting when it fires eccentrically, depending on shoulder position.¹³ The upper and lower trapezius and rhomboids counteract this. Scapular elevation is a function of the upper trapezius, levator scapula, and the upper fibers of the serratus anterior. This is counterbalanced by the scapular depression resulting from the functions of the lower portions of the trapezius and serratus anterior.^9,14

The Scapula in Shoulder Dysfunction

Abnormal scapular kinematics occur as a result of alterations in anatomy, physiology, and/or biomechanics, or musculoskeletal adaptations to these aberrations, and can usually be classified as being proximally or distally derived (Box 3-1).¹⁵ The appropriate term to describe the abnormal scapular movements that occur when the shoulder is moved voluntarily is dyskinesis, as opposed to abnormal involuntary movements, such as in cerebral palsy or Parkinson’s disease, which represent what is termed dyskinesia. When the basic problem occurs proximally and posteriorly to the glenohumeral joint, the observed scapular dyskinesis is considered proximally derived (PDSD). When an abnormality of the glenohumeral joint, subacromial space, clavicle, or acromioclavicular or sternoclavicular joints occurs, the resulting dyskinesis that is usually observed is considered distally derived (DDSD). The exception to this classification is the presence of shortening or tightness of the pectoralis minor or clavipectoral fascia, which fits best into PDSD, despite its anterior position. In the context of the kinetic chain, proximally derived scapular dyskinesis is associated with proximal link or segment weakness or interruption, whereas distally derived dyskinesis is the result of recoil or kickback from a distal link or segment dysfunction. This has important implications for the treatment of shoulder and upper extremity conditions.

PDSD is frequently associated with postural dysfunction. The classic presentation is that of the patient who sits or stands with the head in a forward position, with focal cervical lordosis (usually at C5-C6), thoracic kyphosis, anterior tilt, and internal rotation of the scapula and humeral head.¹ The anterior tilt is typically associated with tightness or shortening of the pectoralis minor muscle tendon unit, whereas the internal rotation of the humeral head usually results from tightness or shortening of the latissimus dorsi, teres major, pectoralis major, and/or subscapularis.^16,17

Proximal kinetic chain weakness can be caused by abnormalities of the lower extremities, lumbopelvic, lumbar, or thoracolumbar deficits. Lumbopelvic weakness with resulting core instability appears to be one of the most common causes of proximally derived scapular dyskinesis in the throwing athlete.⁸ Lumbar lordosis with poor control of the abdominal musculature is frequently associated. Injury to the long thoracic nerve or, less commonly, the spinal accessory nerve, causes weakness and atrophy of the serratus anterior and trapezius, respectively. Long thoracic stretch mononeuropathy is actually more common in overhead athletes than previously thought, and recently has been associated with the use of heavy backpacks by children and young adults (backpack palsy). When these muscles are compromised from neurologic interruption or fatigue, force couple imbalances ensue, and a significant adverse cascade of events occurs (Fig. 3-2). Proprioception is altered, a dyssynchronous muscle firing pattern occurs, and there is an abnormal increase in scapular mobility, which is usually manifested as a loss of external rotation control, with subsequent increased stress on the glenohumeral joint capsule, glenoid labrum, and rotator cuff.^18–20 Increased protraction (scapular internal rotation and anterior tilt) has been shown specifically to increase the strain on the anterior band of the inferior glenohumeral ligament and decrease anterior translation of the humeral head.²⁰ Optimum rotator cuff activation occurs only in the presence of a scapula that is optimally positioned for stability. As a result of scapular dyskinesis, there are increased intrinsic joint loads and decreased force delivered to the terminal segment.⁴

FIGURE 3-2 Cascade of kinetic chain failure. AC, acromioclavicular; GH, glenohumeral; LT, lower trapezius; SA, serratus anterior; SAI, subacromial impingement; SC, sternoclavicular.

Distally derived scapular dyskinesis is very common and is associated with an array of pathologic conditions.^7,18,21-24 Related intra-articular pathology may include labral tears or detachments, capsular attenuation or tears (with resultant instability), focal capsular restrictions such as glenohumeral internal rotation deficit (GIRD) commonly seen in overhead athletes, biceps lesions, adhesive capsulitis, and glenohumeral arthritis. Rotator cuff tendinitis and tears, primary impingement syndrome, and calcific tendinitis have been observed to be associated with scapular malposition. In these cases, the pain and altered biomechanics associated with the pathology appear to cause selective inhibition of the serratus anterior and lower trapezius, with the subsequent events outlined earlier. When glenohumeral internal rotation deficit (GIRD) is present, there is a direct consequence of altered scapular mobility. In any case, there results a vicious cycle of scapular dysfunction and shoulder pathology (see Fig. 3-2).

Subacromial impingement syndrome has historically been associated with abnormal acromial morphology²⁵; however, recent observations have attributed the decrease in the subacromial space height to be more frequently related to a variety of factors that affect scapular position. For example, with increased thoracic kyphosis, there is elevation and anterior tilting of the scapula at rest, decreased upward rotation and posterior tilt of the scapula with glenohumeral elevation, decreased elevation of the glenohumeral joint, and decreased force generated at 90 degrees of scapular plane abduction.²⁶ In addition, it has been shown that with cervical spine flexion of 25 degrees, there is an increase in scapular upward rotation and a decrease in posterior tilting in healthy subjects. Meskers and colleagues²⁷ have demonstrated that the supraspinatus outlet narrows during elevation in the frontal plane from 30 to 130 degrees; however, with external rotation and movement in the horizontal plane, the greater tuberosity moves away from the coracoacromial ligament. Borstad and Ludewig have shown an association between subacromial impingement and anterior tilting, increased internal rotation, and decreased upward rotation of the scapula.²⁸ Cools^29,30 has shown that patients with subacromial impingement demonstrate a decrease in peak force for isokinetic protraction, decreased protraction-to-retraction ratio, and decreased electromyographic activity in the lower trapezius, as well as abnormal muscle recruitment in overhead athletes, with delayed activation of the middle and lower trapezius.

Loss of the normal strut function of the clavicle as a result of a displaced, malunited, or ununited fracture, or a higher degree acromioclavicular joint dislocation, is commonly associated with dyskinetic scapular motion. The pain associated with arthrosis or arthritis of the acromioclavicular or sternoclavicular joint can also cause compromise of the periscapular muscle firing patterns.

In many cases in which shoulder symptoms are chronic, especially glenohumeral instability, glenohumeral internal rotation deficit, and rotator cuff tendon failure, it is difficult to determine whether the scapular dyskinesis was instrumental in causing the intra-articular and/or subacromial pathology or vice versa. Over time, there is a significant overlap as a result of the cyclic nature of the interaction between the segments of the kinetic chain.

It is not always possible to determine the primary underlying cause of abnormal scapular motion; however, it is important to attempt to do so to determine the correct course of action necessary to restore normal shoulder function. In proximally derived scapular dyskinesis, surgical intervention is usually not necessary, because most patients respond to correction of posture and weaknesses and imbalances in the kinetic chain. If the dyskinesis is determined to be distally derived, and the patient does not respond to functional rehabilitation techniques or specific local steroid injections, then surgical intervention is usually required to correct the underlying pathoanatomy to restore the integrity of the kinetic chain. This differentiation can frequently be made by clinical evaluation.

History

A detailed and accurate clinical history is of paramount importance in making consistently precise diagnoses of the cause(s) of shoulder dysfunction. Furthermore, the history helps direct the examination for efficiency and allows the examiner to make postural observations, determine the kinematics of the activity in which the patient is involved, and determine the physical, emotional, and temporal needs of the patient. The history should include questions regarding the onset and duration of symptoms, provocative and alleviating factors, complaints of instability, loss of motion and/or weakness, tingling and/or numbness, mechanical symptoms, and previous similar episodes, treatment, and response to treatment. A thorough history will likely improve the efficiency of the examination by obviating the need to perform some of the diagnostic tests for diagnoses that are clearly ruled out by the information obtained.

To conduct a thorough examination, adequate exposure of the patients’ torso is essential. Female patients should be instructed to bring a sports bra, tank top, or similar garment or be provided a partial gown, which allows for visualization of the scapulae. The physical examination of the shoulder should be a well-rehearsed choreographed series of observations and maneuvers that evaluate the shoulder in the context of the kinetic chain.

Physical Examination

In addition to the clinical history, the key components of the functional examination of the shoulder include assessment of postural alignment, core and lumbopelvic strength and stability, scapulothoracic kinematics, range of motion and movement patterns, muscular imbalances, including lower extremities, hips, and pelvis, glenohumeral joint stability, provocative and corrective maneuvers, and finally palpation.

Assessment of the Kinetic Chain

After the history is completed, the patient is asked to stand in a comfortable posture and observed from the front, back, and side. The patient’s overall standing and seated postures are assessed. Note is made of the relative position of the head and neck and topography of the anterior cervical musculature, elevation or depression of the shoulder girdle, arm position relative to the torso and degree of elbow extension, scapular position, including tilt, rotation, and elevation or depression, abnormal kyphosis, scoliosis or lordosis, pelvic tilt, rotation, or obliquity, and lower extremity malalignment, including hindfoot, midfoot, and forefoot positions. These observations allow the examiner to determine to a great extent the muscle imbalances (e.g., weakness, tightness) that are frequently the underlying pathology causing movement disorders that ultimately cause the presenting symptoms.¹⁷ When carefully assessed, patients with shoulder conditions will frequently demonstrate postural muscle imbalance patterns, which Janda has called upper crossed, lower crossed, and layer syndromes.¹ In the upper crossed syndrome, the patient presents with a forward head, increased cervical lordosis and thoracic kyphosis, rounded shoulders, and scapular protraction as a result of weak cervical flexors, rhomboids, and lower trapezius muscles and tight pectorals, suboccipitals, upper trapezius, and levators. Lower crossed syndrome patients demonstrate increased pelvic tilt, lumbar lordosis, increased lateral pelvic shift, and increased lateral leg rotation because of weak abdominals and gluteus maximus and tight hip flexors and thoracolumbar and extensor muscles. Patients with the layer syndrome have a combination of upper and lower crossed syndromes and have a poorer prognosis because of the long-standing dysfunction.

If the history indicates cervical spine involvement, assessment of this area is necessary to determine whether there is a proximal basis for any observed scapular dysfunction. The components of the complete cervical spine evaluation are beyond the scope of this chapter; however, a cursory examination of the cervical spine should include an assessment of neck range of motion, performance of axial compression testing, including Spurling’s maneuver and palpation of the paraspinal musculature for hypertonicity, tightness, or shortness and the presence of any trigger points.

While the patient is standing, core and lumbopelvic stability are evaluated by having the patient balance on one leg and do a single leg partial squat while the examiner watches for compensatory movements such as pelvic tilt or rotation, internal rotation of the femur, and/or pronation of the midfoot. Flexibility of the hip flexors using the Thomas test is assessed because iliopsoas shortening or tightness has been clearly implicated in the development of many upper and lower extremity dysfunction diagnoses.¹

Scapulothoracic kinematic assessment is accomplished by having the patient slowly elevate and lower the arms in abduction and forward flexion, and observing for dyskinetic scapular motion and/or limitation thereof in the concentric (raising) or eccentric (lowering) phase of scapular stabilizer muscle function (Fig. 3-3). Scapular dyskinesis is most commonly observed during the eccentric phase of lowering the arms from forward flexion. If there is pain or limitation of motion, the test is repeated, with the examiner assisting scapular upward rotation and posterior tilt. If this is successful in decreasing the pain or increasing the motion, it is considered a positive scapular assistance test (SAT).²¹ Having the patient place his or her hands on the hips with the thumbs pointing posterior and observing scapular position provides an efficient and accurate screening assessment of scapular muscle function.

FIGURE 3-3 Scapular winging in a patient with long thoracic mononeuropathy.

While the patient is standing, isolated manual muscle testing of the serratus anterior and rotator cuff muscles is performed. The serratus anterior is evaluated by resisted eccentric contraction with the arm elevated above 90 degrees, with the scapula internally rotated and upwardly rotated (protracted) and the elbow flexed to 90 degrees with a downward force being applied to the upper arm (Fig. 3-4). Weakness is demonstrated by giving way and/or scapular winging. We have found this to be more reproducible and valuable than observing the patient doing a wall pushup. Rotator cuff evaluation involves resisted external rotation in adduction (external rotators), resisted scaption at 90 degrees with the thumb pointing up (supraspinatus),³¹ and resisted internal rotation of the shoulder with the hand on the contralateral shoulder (bear hug test)³² or belly press test³³ (subscapularis). If there is demonstrable weakness of the rotator cuff, the test is repeated with the scapula optimally positioned actively or passively to help differentiate between weaknesses that are primarily a result of rotator cuff pathology and those that are secondary to scapulothoracic dysfunction. This is referred to as the scapular retraction test (SRT).¹⁵ The scapular assistance and scapular retraction tests are functional corrective maneuvers that provide critical information in making a diagnosis of proximally based scapular dyskinesis.

FIGURE 3-4 Eccentric strength testing of the serratus anterior.

In addition to postural observations and assessment of scapulohumeral rhythm, muscle imbalances are assessed with the patient in the supine position. Shortness or tightness of the pectoralis minor muscle tendon unit is confirmed by looking for anterior tilt of the scapula and the amount of space between the examination table and the anterior aspect of the acromion. In these patients, as pressure is applied to the anterior shoulder, the upper arm and scapula externally rotate and the hand and forearm move away from the body. While in this position, evaluation for tightness or shortness of the pectoralis major, subscapularis, latissimus dorsi, and teres major is carried out.¹⁷

Provocative maneuvers, which can be performed with the patient in the seated or standing position, are used in the assessment of subacromial impingement, internal impingement, long head biceps tendinitis, and acromioclavicular joint arthropathy. There is a vast array of published provocative maneuvers for specific shoulder conditions in the orthopedic literature. Typically, each provocative test is claimed to be specific for a single shoulder condition; however, in actuality, there is considerable overlap and the test results can be positive in a variety of disorders, especially when anterior shoulder pain is a predominant symptom. To maintain efficiency during the performance of the office examination, it is important that clinicians select tests that are determined to be most productive in their hands rather than to try to do all the tests on every patient.

Pain Control

Because pain is the presenting symptom of most patients, it is important to manage and control the patient’s pain early in the treatment process. In the nonoperated or postoperative patient, this may involve the recommendation for nonsteroidal anti-inflammatory drugs and, in some cases, prescription analgesics. We have found that the use of perioperative local nerve blocks such as suprascapular nerve and interscalene blocks are helpful for establishing early control of postoperative pain and a smoother postoperative course. In addition, immobilization or more accurately protected range of motion is advised. An early postoperative visit to the physical therapist allows the patient to become informed about the expected goals and course of therapy, establish control of her or his own physical and emotional situations, provide expectations with regard to acceptable and unacceptable pain, learn a home exercise program, and be given guidelines for self-progression. The physical therapist may use modalities such as ice and electrical stimulation as necessary to control the discomfort; however, the patient should be weaned from modalities other than ice as soon as possible so that the rehabilitation process is functional rather than passive.

A painful joint will not progress. During rehabilitation, pain is a sign that the wrong exercise is being done for that phase of the patient’s recovery, that the exercise is being done incorrectly, or that the muscles are showing fatigue. The patient should not attempt to push through the pain. Lack of pain is a major criterion for advancement in rehabilitation protocols.

Range of Motion

Soft tissue restrictions must be addressed early in the rehabilitation process to achieve normal scapular positioning. Areas of particular concern in patients with scapular dyskinesis include the pectoralis minor, which causes anterior tilting, upper trapezius and levator scapulae, which cause elevation, infraspinatus and teres minor, which prevent normal internal rotation and posterior tilting, and latissimus dorsi, teres major, pectoralis major, and subscapularis, which cause internal rotation of the humerus. In patients in whom GIRD is present, the posterior inferior capsule contracture must be corrected to restore normal glenohumeral kinematics.

In the postsurgical patient, protected range of motion is initiated early in the postoperative period to avoid stiffness. The direction and degree of motion and the timing of passive, active assistive, and active range of motion are determined by the procedure, as well as by the quality of the patient’s tissue, quality of the repair or reconstruction, desired or required activities of the patient, patient age, genetic factors, and experience and judgment of the surgeon.

Postural Alignment

For the body to function properly, it must be in proper alignment. Upper quarter posture depends on correct positioning of the pelvis, lumbopelvic region, lower extremities, cervical and thoracic spine, scapula, and shoulder. The physical therapist, through soft tissue releases and stretching, is able to address these postural components. Rehabilitation exercises should be carried out with a neutral spine, appropriate pelvic position, and proper activation of trunk musculature. Shoulder protraction, excessive cervical and lumbar lordosis, and thoracic kyphosis should be corrected whenever possible. Other postural abnormalities, especially thoracic hypomobility, which is commonly seen in these patients, must be corrected early in the rehabilitation process. Exercises should be performed in a position that replicates function. Because of recent adverse changes in insurance reimbursements for physical therapy services and the limitation of allowed visits, we stress having patients take responsibility for correcting their alignment and performing their exercises correctly to make the time with the therapist more productive.

Core Stability

Core stability can be defined as the ability to control the position of the trunk over the pelvis to allow optimum production, transfer, and control of force and motion to the terminal segment in integrated activities.⁴⁰ The core is central to almost every kinetic chain of sports and work activities and therefore, the importance of core strength, balance, endurance, and control in maximizing function and minimizing injury cannot be overstated. Zazulak and associates⁴¹ have explained that for a dynamic system to be stable, there must be accurate and complete feedback information from sensory receptors to the central nervous system (CNS). The CNS must then use this information to generate appropriate input to the muscles and the information accurately relayed to and from the CNS,. The muscles must have sufficient power to bring about quick changes in joint motions. Hodges⁴² has demonstrated that before arm or leg movement is initiated, the transversus abdominis is consistently activated first to increase the intra-abdominal pressure and stabilize the torso for the anticipated action, thus preventing postural perturbation. Therefore, strengthening of the abdominal musculature and the other core muscles is done early in the rehabilitation process. Much of the central core is made up of larger bulkier muscles, which when functioning properly create a rigid cylinder that prevents body perturbation and allows a more stable base for the more distal components of the kinetic chain. Neuromuscular training, which includes proprioceptive exercise, perturbation, and correction of body sway, allows for improved retraining to restore normal movement control. We have found that the incorporation of the principles of Pilates-based exercises is helpful in reestablishing core strength.

Kinetic Chain

The simple task of lifting the arm integrates the entire body in a feed-forward motor pattern.⁴³ Prior to the onset of anterior deltoid function, the soleus deactivates and the following muscles are sequentially activated: tensor fascia lata, rectus femoris, hamstrings, glutei, and erector spinae. The thoracolumbar fascia connects the lower limbs via the gluteus maximus to the upper limbs via the latissimus dorsi, covers the deep muscles of the back and trunk, including the multifidi, and has attachments to the internal obliques and transverse abdominis muscles, thus integrating the core into the kinetic chain for activities such as throwing. In looking at the contribution of joints and planes of motion to overall task acuity in throwing, Tripp and coworkers⁴⁴ have shown that the acuity of proximal joints has larger effects on upper extremity tasks than distal joints, and that small deficits proximally develop into larger deficits distally and ultimately have more of an effect on overall acuity of the extremity. Proper activation of trunk musculature and normal trunk and leg strength and flexibility facilitate scapular position, reinforcing the concept of rehabilitation progression from proximal to distal. When possible, correct proximal weaknesses first and then add the upper extremity. During this time, scapular and upper extremity exercises can be done in the seated position to separate the dysfunctional segments. The rehabilitation program should integrate functional movement patterns as soon as possible.

Scapular Position

Ability to position the scapula properly by external rotation and posterior tilting (retraction) and downward rotation (depression) is critical to the success of any shoulder rehabilitation program. The periscapular muscles control the position of the scapula during concentric and eccentric function. For example, when the serratus anterior functions concentrically, it works as a scapular protractor; however, its eccentric function during throwing or overhead activities is to rotate the scapula externally and thus it is important for this muscle to be strengthened eccentrically. Patients should be taught very early in the process (preoperatively if surgery is contemplated) how to “find” their scapula and position it properly to enhance humeral head compression by the rotator cuff and decrease subacromial impingement caused by anterior tilting of the acromion. Normalizing the position of the scapula improves rotator cuff strength by 23% in elevation⁷ and helps reestablish normal force couples for scapular stabilization and elevation. In some cases, it is helpful to use single- or dual-channel surface biofeedback techniques to monitor muscle activity with auditory and/or visual cues using dual mirrors. We have found inhibition of the upper trapezius or latissimus dorsi and activation of the lower trapezius to be particularly beneficial. It is frequently necessary to reestablish normal length of the periscapular muscles, especially the pectoralis minor, to position the scapula appropriately. It is not uncommon for the postoperative patient to develop subacromial bursitis as a result of inability to position the scapula correctly. Various kinesiotaping and bracing techniques have been developed to decrease the incidence of this occurrence. These techniques do not hold the scapula in position; rather, they provide a proprioceptive link to the brain to stimulate the scapular stabilizing muscles to rotate the scapula externally and tilt it posteriorly (retract and depress) to widen the subacromial space. Walther and colleagues⁴⁵ have shown that bracing improves shoulder function. This is consistent with our observations using kinesiotape or the Spine and Scapula Stabilizing (S3) brace or Posture Shirt (Alignmed, Santa Ana, Calif) or the Intelliskin shirt (http://www.intelliskin.com) for patients with postural dysfunction and difficulty positioning their scapulae.

Functional Progression

Progression is based on acquisition of function rather than time; therefore, the phases of the rehabilitation program are based on obtaining normal proximal control and proceeding distally. Learning speed and neuromuscular control differ among patients as a result of factors such as different learning abilities, intelligence, age, ability to focus, or comorbidities, such as diabetes. Progress should be monitored by the overall trend of improvement rather than by chronologic landmarks. In general, exercise progression is from general to specific, simple to complex, easy to difficult, proximal to distal, single to multiple plane, isometric stability to isometric movement, stability to mobility, controlled mobility to skill movements, controlled to uncontrolled environment, horizontal to vertical movements, and unidirectional to multidirectional movements.⁴⁶ In addition, the patient moves from lesser to greater volume, lesser to greater intensity, and lesser to greater frequency.

Therapeutic Exercises

Strengthening exercises should incorporate whole-body movements, whenever possible. Patients should be taught to isolate muscles and then train muscle groups in a coordinated, synchronous pattern to reestablish force couples, and thus functional patterns and proprioception. Muscles should be strengthened in concentric and eccentric patterns, with emphasis on control of eccentric movements.

Closed-chain exercises replicate both the physiologic and biomechanical patterns of movement. Physiologically, there is coordinated muscle firing, resulting in rotator cuff muscle coactivation, reciprocal inhibition, and proprioceptive feedback. Biomechanically, there is increased joint compression with decreased shear, translational, and distractive forces on the glenohumeral joint and rotator cuff, and resultant improved control of joint movement and reestablishment of scapulohumeral rhythm. This allows the patient to increase strength and motion while protecting the repaired and/or healing tissue.^47–49 Open-chain exercises, which allow movement of the terminal segments, increase the stress on the soft tissue structures; however, they are important in completing the recovery to normal function. These exercises involve concentric movement against gravity with no fixation feedback (e.g., free weight training). In general, progression is from closed-chain to open-chain exercises as healing, strength, and control improve. Incorporation of motor patterns, which include the legs and trunk, should be done as soon as the patient can tolerate these activities. Sequential distal segment activation is facilitated with exercises that connect the hip and trunk with the scapula and the scapula with the rotator cuff. Some exercises are performed in diagonal patterns to reproduce the serape effect.

Quality is more important than quantity. The patient should focus on control rather than on the number of repetitions. Strengthening exercises should never be performed past the point of fatigue, which is frequently manifested by pain or loss of form while doing the exercise. In the postoperative patient, elevation of the scapula is an early sign of fatigue of the scapular stabilizing muscles and will frequently lead to subacromial bursitis, which inhibits functional progression.

Cardiovascular Training

Aerobic activity is encouraged early in the rehabilitation process to enhance blood flow and healing, as well as encourage a feeling of control and well-being for the patient. Postoperative patients can use a stationary bike, Stairmaster, treadmill for walking, or elliptical trainer while still in a sling as long as they are comfortable and there is no impact or downward traction, such as with running. Impact activities such as running are usually deferred until healing is more advanced, which is usually between 2 and 3 months postoperatively, depending on the procedure.