Treatment of the scapula and shoulder has traditionally incorporated exercises that have been shown to elicit large amounts of muscle activity per electromyography. Although the seminal studies identified maneuvers that can actuate various muscles to high degrees of electrical activity, the foundational work was performed on asymptomatic individuals. Furthermore, the identified maneuvers were often performed in an isolated manner with the body in a vertical or horizontal stationary position. Considering the scapula is a link within the kinetic chain, these isolated maneuvers may not reestablish scapular mobility and control in the necessary motor patterns that require integrated use of the majority of the kinetic chain segments. Failure to incorporate the kinetic chain throughout the rehabilitation process, from the earlier phases of treatment through the later phases, could lead to less than optimal rehabilitation outcomes. In some instances, the scapula and shoulder can be overtly dysfunctional. In these instances, minimizing the degrees of freedom via the elimination of gravity-dependent positions may be necessary. However, the majority of clinical cases involving scapular dysfunction should allow for the incorporation of sitting or standing positions in the early phases of rehabilitation. As such, an approach to manage altered scapular motion in an integrated manner has been described.
A kinetic chain rehabilitation framework for shoulder dysfunction describes a rehabilitation approach that focuses on three critical characteristics.1 First, patients are upright during exercise performance rather than positioned supine or prone when possible to simulate functional demands. Second, the lever arm on the shoulder and trunk is shortened to reduce the load on the injured arm. Finally, arm motions should be initiated using the legs and trunk to facilitate activation of the scapula and shoulder muscles, which is a typical motor pattern of motion. This framework was later expanded to include a set of progressive goals2: (1) establish proper postural alignment and motion; (2) facilitate scapular motion via exaggeration of lower extremity/trunk movement; (3) exaggerate scapular retraction in controlling excessive protraction; (4) use the closed chain exercise early; and (5) work in multiple planes.
In this first stage of the kinetic chain approach, inflexibilities and restrictions should also be addressed. These deficiencies can impede progressions if left unattended and delay the treatment process. Altered posture is known to decrease strength and motion at the glenohumeral joint and decrease motion of the scapula.3 Proper posture and motion can be achieved with a logical and progressive treatment plan to restore skeletal segmental stability and mobility through soft tissue mobility and joint mobilization. Employing interventions such as stretching of the short head of the biceps brachii and pectoralis minor with a door frame stretch (Figure 1A), the infraspinatus/teres minor with a cross-body stretch (Figure 1B), and the latissimus dorsi with a prayer stretch (Figure 1C) are effective. Anterior directed joint mobilizations for the thoracic spine/ribs is recommended if immobility has been identified in this area.
(A) Doorframe stretch. (B) Cross-body stretch with stabilization of scapula. (C) Prayer stretch.
Caution should be taken if attempting to manually mobilize the scapula. Clinicians often place their hands “under” the medial aspect of the scapula in an attempt to stretch the medially attached muscles or loosen the fascial tissue. If performed with too much force and/or compression, this technique can have deleterious consequences such as creating irritation between the muscles and thorax or detaching the medial muscles from the scapula. Instead, clinicians should attempt to “glide” the scapula in the superior, inferior, medial, and lateral directions by placing one hand below the inferior angle and above the supraspinous fossa.
Scapular Motion Facilitation
Arm function in front of the body or overhead requires that the scapula obtains a position of posterior tilt and external rotation, which allows optimal shoulder muscle activation that is synergistic with trunk and hip musculature. This kinetic chain pattern of activation then facilitates maximal activation of the muscles attached to the scapula. This integrated sequencing allows the retracted scapula to serve as a stable base for the origin of all rotator cuff muscles, allowing optimal concavity-compression to occur. Therefore, implementing scapular stabilization exercises that incorporate lower extremity stability and muscle activation would be appropriate. For example, shoulder exercises are often performed with the body stationary. This would be counterintuitive to the kinetic chain concept because the arm is being forced to perform as an isolated structure rather than as part of an integrated unit. Using a traditional “row” for context, a patient would be asked to sit or stand in a stationary position and then move the arms from a forward flexed position with the elbows extended to an extended position with the elbows flexed (Figure 2A). The kinetic chain alternative to this maneuver would be to simply begin with the knees slightly flexed, the trunk flexed at the waist, and the arms in a forward flexed position as noted above (Figure 2B). The patient would then actively extend the knees and trunk while simultaneously moving the arms to the extended position (Figure 2C). This added knee and trunk motion “facilitates” scapular motion by allowing the scapula to more fully medially translate, which in turn more closely mimics kinetic chain function.
(A) Traditional row with body stationary. Kinetic chain row (B) beginning with trunk and knee flexion and (C) moving to a fully erect position.
Patient position should also be considered during rehabilitation exercise performance. It is common to perform various shoulder exercises in supine and prone positions. Although patients can perform exercises in these positions, it is questioned whether they should instead perform exercises while standing. This question has merit because the standing position allows a patient to use the entire kinetic chain and be retrained in motor control. The standing position appears to decrease the chance that one or more segments within the kinetic chain could be overlooked because they would be used in a manner similar to activities of daily living and sport. By this mechanism, the standing position allows rehabilitation to be more functional. Furthermore, greater amounts of joint position sense errors at the shoulder have been shown to occur when patients are placed in supine positions.4 This suggests that traditional methods of performing shoulder exercises in supine and/or prone positions may need to be reconsidered. In some cases, patients may need to begin in a seated position. This is recommended for patients with inadequate balance or those who are in the early postoperative phases of recovery who may be using opioid pain medication.
Controlling Protraction and Exaggerating Retraction
Excessive scapular protraction does not allow optimal rotator cuff activation to occur. The muscles responsible for performing scapular retraction can help control scapular protraction through eccentric control. When optimized, these muscles can properly maintain scapular stability, thus decreasing excessive protraction with arm movement. A basic exercise to use in this phase would be conscious correction of the scapula using visual feedback.
Scapular strength and motion is best achieved with active scapular movement performed by the patient. To optimize arm function, the active “setting” of the scapula (more commonly known as conscious correction) in a position of retraction has been advocated as the initial step in rehabilitation.5 Most clinicians have used “scapular squeezing” as an exercise, but experience has shown that little instruction beyond “squeeze your shoulder blades together” is conveyed to the patient. It is common for patients to “shrug” or simply be unable to perform this maneuver correctly, forcing clinicians to closely monitor the motion for potential errant movements (Figure 3A). It is possible that patients struggle with performing conscious scapular correction properly because the free moving scapula is mostly characterized by accessory motion (ie, involuntary motion) while also being posteriorly located and therefore unseen by the eyes.
Conscious correction (A) with shrug and (B) using visual feedback.
Visual acuity is the strongest type of feedback humans use for knowledge of results, knowledge of performance, and overall motor control. It is possible that the scapular motion alterations seen by clinicians during arm movement such as upper trapezius hyperactivity and vertical translation of the scapula, as well as the inability to properly place the scapulae in a position of retraction during conscious correction, could be due to the inability of the patient to see the scapula moving. Although adult patients can benefit from verbal external feedback provided by the clinician, there is a balance between too little and too much feedback that must be defined. Too little feedback does not inform the patient of occurring motion errors, whereas too much feedback creates a dependency of the patient on the verbal feedback, not allowing learning to occur. Supplemental equipment that could assist patients with performing conscious scapular correction would be reflective devices including mirrors or mobile devices that have a self-portrait function (Figure 3B).
Early Closed Chain Implementation
Rehabilitation activities based on the kinetic chain have been grouped into open and closed chain. Typically, closed chain exercises are implemented early in the rehabilitation process. The controlled exercise environment, ability to focus on specific ranges of motion, and ability to unload the rotator cuff and other tissue around the scapula make the use of closed kinetic chain exercise advantageous in early rehabilitation. These types of exercises are best suited for reestablishing the proximal stability and control in the links of the kinetic chain such as the pelvis and trunk. For example, if a patient presents with shrugging during arm elevation, then it can be assumed that the lower trapezius and upper trapezius (secondary upward rotators) are not working with the middle trapezius and serratus anterior (primary upward rotators) effectively enough during the dynamic task to control scapulohumeral rhythm. A closed chain exercise such as the low row (Figures 4A–4B) should be used because the short lever positioning in conjunction with the pelvis and trunk acting as the driver facilitates lower trapezius and serratus anterior coactivation, which decreases the activation of the upper trapezius.6 Once the normal activation pattern of retraction and depression has been restored, then more challenging exercises can be employed. Open chain exercises, which generate greater loads in comparison to closed chain activities, should be used later in rehabilitation programs.
Low row (A) beginning with knees flexed and hand against the table and (B) ending with the patient standing erect while pushing back against the table.
Open chain exercises that require the arm to be maintained in a straight position throughout a range of motion and to be further away from the body (ie, long lever exercises such as Ts, Is, and Ys) have been shown to elicit high levels of muscle activity7–9 and by consequence increase the demands on the muscles (Figure 5A). Conversely, exercises that are performed with the elbow in 90 degrees of flexion and/or with the arm close to the body (ie, short lever exercises such as rowing, robbery, or lawn-mower) elicit lower levels of muscle activity and have decreased demands on the muscles (Figures 5B–5C).6 Either long lever or short lever exercises are acceptable to use in rehabilitation, but the timing of implementation may cause different outcomes. Due to the physical demands of long lever exercises, patients may experience irritation or soreness during or after the performance of the maneuvers when they are employed early in the rehabilitation process. Additionally, it is also assumed that the greater demands require more effort to be exerted to perform the exercises, which may conflict with a patient attempting to establish scapular control. This could potentially create a situation where the patient becomes fatigued early in treatment sessions, which in turn could cause the patient to use compensatory movement patterns during exercise performance. Short lever exercises allow patients to focus on the stability function of the scapula and can often be performed with greater ease compared to long lever exercises. Therefore, it is recommended that short lever exercises be used in the earlier phases of rehabilitation. Once these maneuvers have been mastered and can be performed at high levels of sets and repetitions (4 to 5 sets of 10 to 12 repetitions), then the progressive integration of long lever exercises can occur.
(A) Long lever “Y” exercise. Short lever lawnmower exercise (B) beginning with trunk and knee flexion and (C) ending with patient standing erect while using trunk rotation to achieve scapular retraction. (D) Combination of long lever exercise with trunk rotation.
Working in Multiple Planes
During the functional phase in the latter stages of the rehabilitation process, the transverse plane should be exploited using diagonal and rotation exercises. For example, it has been shown that scapular rotations of posterior tilt and external rotation, as well as activity of the lower trapezius, can be increased by simply adding trunk rotation to traditional stationary exercises such as humeral external rotation and forward elevation (also known as Is)10 (Figure 5D). Scapular rotations, although they move around an axis, actually cross planes of motion and do not occur in a linear fashion. This is due to the ellipsoid shape of the thorax and the fiber orientation of the muscles acting on the scapula. The complexities of the scapular motions should not be ignored because the patient will ultimately have a less successful outcome. Using various planes of motion that mimic individual patient function would be recommended.
Rehabilitation programs for scapular dysfunction should follow the evaluation of scapular dysfunction philosophy, which views the scapula as a link in the kinetic chain. The complexity of scapular motion and the integrated relationship between the scapula, humerus, trunk, and legs suggests a need to develop rehabilitation programs that involve all segments working as a unit rather than isolated components. Obtaining mobility early in the rehabilitation would in turn allow for more fluid, task-specific movements to occur. Furthermore, integrating the legs and trunk more often in the rehabilitation process (as allowed by the patient's impairments and/or injury) would closely mimic activities of daily living, sport, and work tasks. The integrated approach could enhance motor control, thus enhancing rehabilitation outcomes.