The rehabilitation of the shoulder has evolved over the past 20 years. In the past, the rehab program focused on strengthening the rotator cuff muscles. Then Dr. Kibler and others taught us to also treat the scapular muscles and scapula posture. Since then numerous articles have been published suggesting GIRD (glenohumeral joint internal rotation deficit) was the cause of shoulder injuries and should be treated and others have suggested total rotational range of motion (TROM) is more important.
Since these motion concepts have been introduced, various forms of exercise has been advocated such as eccentrics, plyometrics, weighted ball throwing, and other exercise programs.
I have always believed that the rehab of the overhead athlete is based on a careful & thorough clinical examination and differential diagnosis. Once that has been established then a multi-phased rehab program can begin. In the first phase, when the patient is acute, the focus should be on reducing pain & inflammation, normalizing motion, enhancing dynamic stabilization of the glenohumral joint, improve posture, and patient education (which means no throwing !).
I believe this article which we just published will take you through a four phased rehab program which you will find useful and effective. Remember, there are numerous causes of shoulder pain in the overhead athlete. We are discussing the physical causes, but other causes include improper throwing mechanics, overtraining, improper training, too much throwing, and psychological factors. Good luck with the rehab of these challenging and fun patients.
Advanced Sports Medicine Concepts and Controversies Rehabilitation of the Overhead Throwing Athlete: There Is More to It Than Just External Rotation/Internal Rotation Strengthening
Kevin E. Wilk, PT, DPT, FAPTA, Christopher A. Arrigo, MS, PT, ATC,
Todd R. Hooks, PT, ATC, OCS, SCS, NREMT-1, CSCS, CMTPT, FAAOMPT,
James R. Andrews, MD
The repetitive nature of throwing manifests characteristic adaptive changes to the shoulder, scapulothoracic, and hip/pelvis complexes that result in a set of unique physical traits in the overhead throwing athlete. An effective rehabilitation program is dependent upon an accurate evaluation and differential diagnosis to determine the causative factors for the athlete’s pathologic features. The treatment program should be individualized with specific strengthening and flexibility exercises to achieve the dynamic stability that is required for overhead function. In this article we describe the characteristics of the throwing shoulder, along with a multiphased rehabilitation program that allows for the restoration of strength, mobility, endurance, and power and is aimed toward a return to unrestricted sporting activity. We also describe exercises that link the upper and lower extremities because of the importance of core control and leg strength in the development of power during the act of throwing. Additionally, proper throwing mechanics, utilization of pitch counts, appropriate rest, and proper off-season conditioning will help decrease overall injury risk in the overhead throwing athlete.
The repetitive nature of overhead throwing causes the shoulder complex to be a common site of disfunction in overhead throwing athletes. Conte et al  reported that shoulder injuries represented 27.8% of all disabled days among professional baseball players.
Major League Baseball pitchers have been shown to have a 34% greater upper extremity injury rate compared with position players, and when pitchers were placed on the disabled list, they remained on the list for an average of 20.10 more days (74.25 days for pitchers compared with 54.15 days for position players). According to the National Collegiate Athletic Association Injury Surveillance System, shoulder strains/tendinitis injuries equated to 8.2% of all injuries occurring during games and 16.7% of injuries during practice . The shoulder has also been reported to be the most commonly injured region in high school baseball players, representing 34.2% of all injuries in pitchers and 24.9% in catchers, with an overall prevalence of 17.6% for all positions . The throwing motion places tremendous forces across the glenohumeral joint, with angular velocities reaching 7250/s and anterior shear forces approaching 50% of body weight [5-7]. Throwing also generates high levels of muscular activity, with forces reaching 120% of maximal volitional isometric contractions . Although an inherent degree of mobility is needed during the throwing motion, the athlete is dependent upon dynamic stability while throwing to minimize the potential for injury. The “thrower’s paradox,” as described by Wilk et al , illustrates the essential rehabilitation challenge in the overhead throwing athleted that the shoulder must be loose enough to throw yet stable enough to prevent injury. The inability to successfully balance this paradox is the primary reason overhead throwing athletes are commonly injured and that their successful return to athletic participation can be difficult to manage.
Musculoskeletal adaptations occur within the shoulder joint complex as a result of throwing at a young age, throwing frequently, and high-volume throwing. Adaptations can occur to osseous structures (eg, the humeral head and glenoid fossa) or soft tissue structures (eg, the rotator cuff and glenohumeral joint capsule). In addition, postural adaptations to the scapular position are also apparent. Furthermore, specific adaptations occur at the hip joint complex as a result of throwing . The focus of this article is a discussion of a thorough rehabilitation process for the overhead thrower and the concept that rehabilitation must entail more than just rotator cuff exercises when an athlete experiences shoulder pain; rather, the entire body needs to be comprehensively examined and systematically treated to ensure an uncomplicated return to overhead throwing.
Key Rehabilitation Principles
The keys to the successful rehabilitation of the overhead throwing athlete are tied to the ability to adequately ascertain and appropriately address the unique characteristics and underlying pathologic processes inherent to the thrower’s shoulder. These characteristics and processes include the intrinsic soft tissue and osseous adaptations evident during physical examination, as well as extrinsic factors that include variables such as frequency, intensity, and duration of throwing. The keys to successful rehabilitation of the overhead throwing athlete include the importance of proper shoulder mobility, the need for a functional scapular base of support, the critical role of dynamic stability and neuromuscular control, and the importance of core, hip, and leg strength.
Normalizing Shoulder Mobility
Normalizing shoulder motion is essential for successful rehabilitation of the throwing athlete. Particular attention should be directed to restoring shoulder internal rotation (IR), total rotational motion (TRM), and horizontal adduction. It is common for the overhead thrower to exhibit a significant loss of IR. This loss of IR is often referred to as GIRD (glenohumeral internal rotation deficit) and is defined as a loss of IR in the throwing shoulder of 17 or more when compared with the nonthrowing arm [11,12]. The loss of IR seen in throwers is most often due to osseous adaptations of the humerus and posterior muscular tightness, which have been suggested to cause specific shoulder injuries, including internal impingement and superior labral lesions [12,13]. TRM is the value derived by adding the IR and external rotation (ER) measurements in 90 of shoulder abduction . This total arc of rotation has been shown to be within 5 bilaterally in asymptomatic professional pitchers . A TRM arc greater than 5 has also been shown to be a contributing factor in the development of throwing shoulder injuries [9,14,15]. Eccentric muscle contractions have been correlated with a rise in passive muscular tension and a loss of joint range of motion (ROM) . It is our experience that baseball players often describe generalized tightness in the musculature of the posterior shoulder after pitching. The muscles responsible for ER of the shoulder exhibit high eccentric muscle activity during the acceleration portion of the throwing motion as the shoulder internally rotates between 6000 and 7000 per second [5-7]. It appears that the muscle activity involved in baseball pitching may be responsible for an acute loss in IR immediately after pitching. Previous studies examining the effect of repetitive eccentric contractions have shown a loss of joint ROM in the upper and lower extremities during testing .
We do not believe that the loss of IR is routinely due to posterior capsular tightness. Most throwers exhibit significant posterior laxity when evaluated . Borsa et al  studied glenohumeral translation in 43 healthy baseball pitchers and reported an increased posterior translation compared with anterior translation in the throwing arm and no difference in translation between dominant and nondominant shoulders .
Functional Scapular Base
Scapular stability is crucial for normal asymptomatic arm function, especially in an overhead throwing athlete. Several authors have emphasized the importance of scapular muscle strength and neuromuscular control in contributing to normal shoulder function [16,18-20]. The force couples of the upper trapezius, serratus anterior, and lower trapezius play an integral role in the throwing motion by posteriorly tilting, elevating, and upwardly rotating the scapula, thereby placing it in a functionally appropriate position for successful throwing.
Throwers frequently exhibit rounded shoulders and forward head posture. This postural positioning is associated with muscle weakness of the scapular retractors due to prolonged elongation and altered length tension relationships between synergistic muscle groups that elevate, posteriorly tip, abduct, and protract the scapula during active arm elevation. In addition, the scapula on the throwing side may often appear protracted, depressed, and anteriorly tilted in relationship to the contralateral scapula. An anteriorly tilted scapula has been shown to contribute to a loss of glenohumeral joint IR [21,22]. In overhead throwers, it is our experience that this abnormal scapular positioning is associated with pectoralis minor muscle tightness, coracoid pain, lower trapezius muscle weakness, and a forward head posture. In some instances, tightness of the pectoralis minor muscle can lead to axillary artery occlusion and neurovascular symptoms such as arm fatigue, pain, tenderness, and cyanosis [23-26]. Tightness of the pectoralis minor most frequently results in an anteriorly tilted scapula and may contribute to shoulder pain during throwing or exercising. The lower trapezius muscle is an important muscle in arm deceleration because of its controlling effect on scapular elevation and protraction . Weakness of the lower trapezius muscle may result in improper throwing mechanics or a greater propensity toward developing shoulder symptoms while throwing. Careful assessment of scapular position, mobility, and strength in the thrower is essential to ensure symptom-free overhead athletic function.
Neuromuscular Control and Dynamic Stability
Neuromuscular control plays a critical role in the generation of dynamic shoulder stability [27,28]. In the shoulder, neuromuscular control refers to the constant interplay of afferent input and efferent output required to produce stable and effective volitional movement.
The primary stabilizers of the glenohumeral complex produce a co-contraction that enhances humeral head stability during active arm movements. The combined effect of the rotator cuff musculature is a synergistic action that creates humeral head compression within the glenoid and counterbalances the shearing forces generated by the deltoid [29,30]. Additionally, active glenohumeral joint stability is provided through blending of the rotator cuff tendons in the shoulder capsule, which produces tension with the capsular ligaments. As the rotator cuff contracts, fibers of the muscle tighten the capsule, thus enhancing the static stabilizers of the glenohumeral joint, which accentuates the centering of the humeral head within the glenoid fossa.
Core and Leg Strength and Proper Functioning
The importance of a strong and properly functioning core, hips, and legs cannot be overemphasized in the rehabilitation of the overhead throwing athlete. Many of the exercises we perform today focus on linking the shoulder and the lower extremity to facilitate the transfer of power from the lower extremity to the arm during throwing. These exercises are frequently performed on a stability ball to challenge the core and hips in the process. We frequently see poor core, hips, and leg strength in adolescent and preadolescent athletes.
Their posterior chain musculature (gluteals, hamstrings, and erector spinae) is frequently underdeveloped and lacks adequate control and sequential activation during basic athletic movements. Beckett et al  reported a high prevalence of poor single-legged squat test results in these athletes. We will discuss numerous exercises and drills for this age group that are designed to emphasize core, hip, and leg strength in the rehabilitation process.
Multi-Phased Rehabilitation Program
The optimal rehabilitation program for the throwing athlete involves a progressive, sequential, multi-phased approach that is based on the findings identified during the physical examination with regard to pathologic findings, specific structures involved, and the root cause of the condition. The 4 rehabilitative phases for the overhead throwing athlete are presented in Table 1. This approach should be paired with the therapist’s knowledge of the sequential and progressive implementation of principles related to the restoration of strength, dynamic stability, and neuromuscular control in the overhead throwing athlete. Each phase represents a progression in which exercises become more aggressive and demanding and the stresses applied to the shoulder joint gradually intensify.
Phase 1: Acute Phase
The goals in the initial phase of the rehabilitation program are to diminish pain and inflammation, normalize motion, correct postural adaptations, normalize muscle balance, restore proper muscle activation, and re-establish baseline dynamic joint stability.
During the acute phase of treatment the athlete may be prescribed nonsteroidal anti-inflammatory drugs and/or a local injection; however, clinically, local therapeutic modalities such as ice, laser treatments, iontophoresis, and/or electrical stimulation are also used to diminish pain and inflammation. The athlete is educated regarding activity modification/avoidance (such as throwing, strenuous activities, and exercises), as well as posture while sitting and standing to increase subacromial space .
After the resolution of acute inflammation, the rehabilitation specialist may implement the use of moist heat to increase local circulation and improve soft tissue extensibility, including the joint capsule and musculotendinous tissues. This type of passive warm-up is combined with ROM and joint mobilization techniques to improve joint mobility and reduce symptoms. During this initial phase, it is essential to normalize the patient’s shoulder joint passive ROM (PROM). The clinician may utilize soft tissue mobilization techniques with the goal of improving tissue extensibility, reducing pain and guarding, and preparing the athlete for activities. Decreased electromyography (EMG) activity of 23% with a corresponding reduction of 32% ER force production has been documented in a painful shoulder, lending credence to the importance of pain reduction to permit restoration of normal rotator cuff recruitment . Additionally, to diminish pain and muscle guarding via stimulation of the type 1 and 2 mechanoreceptors, active-assisted ROM (AAROM), light manual stretches, and grade 1 and 2 joint mobilizations are also performed [34-36].
During the acute phase of rehabilitation, the clinician should ensure the normalization of motion by incorporating AAROM, PROM, manual stretches, and mobilization techniques. Although all aspects of shoulder mobility should be assessed, it is common for the overhead throwing athlete to display a loss of IR and horizontal adduction. The loss of IR is commonly described as GIRD. As previously described, a loss in IR of 17 or more in the throwing shoulder has been found in persons with shoulder and elbow injuries [37-40]. Glenohumeral IR loss has been largely attributed to osseous adaptations, but other structures can contribute to the loss of IR, such as posterior rotator cuff tightness, posterior capsule tightness, and an anteriorly tilted scapula [9,41-46].
A proper clinical assessment to differentiate between altered scapula positioning, posterior glenohumeral joint capsule tightness, and/or posterior shoulder muscle tightness as the causative factor(s) of the diminished ROM is essential for the clinician to guide the appropriate treatment selection to restore IR. Mobility of the glenohumeral joint capsule can be assessed by centering the humeral head within the glenoid fossa and assessing the amount of translation available, comparing dominant with nondominant shoulders. In addition, the clinician can perform diagnostic ultrasound imaging of the humeral head, in particular the bicipital groove, and determine the amount of humeral head retroversion. Several investigators have documented the use of ultrasound as a reliable and valid method of determining humeral retroversion [47-51].
A complete assessment of posture and scapular mobility should be conducted, because an anteriorly tilted, protracted, and depressed scapular position is often seen when compared with the nonthrowing side.
This positioning can create muscle weakness and/or inhibition of the scapular retractors as a result of an altered length tension relationship of the scapular force couples. Lower trapezius weakness and/or poor muscle activation with delayed muscle firing can result in improper scapular mechanics and potential shoulder symptoms, which must be addressed with focused strengthening activity . In addition, pectoralis minor tightness and coracoid pain are often noted. The decreased flexibility of the pectoralis minor can cause neurovascular symptoms including arm fatigue, pain, tenderness, and cyanosis due to occlusion as they pass underneath this muscle [25,26]. The pectoralis minor muscle can be assessed for tightness by having the patient stand against a wall and measuring the distance from the wall to the anterior acromial tip; a side to side asymmetry greater than 3 cm is considered abnormal . We commonly perform pectoralis minor muscle stretches with the scapula placed in a retracted and posteriorly tilted position in 90 of shoulder flexion as the humerus is placed in an abducted and ER position [53,54].
The posterior shoulder is subjected to repetitive eccentric loads during throwing, which can result in increased internal stiffness and decreased shoulder ROM . The modified sleeper stretch (Figure 1), modified cross-body horizontal adduction stretch (Figure 2), and horizontal adduction stretch with concomitant IR (Figure 3) are performed to improve flexibility of the posterior shoulder . The posterior capsule has been shown to exhibit significant laxity in throwers who exhibit GIRD, and therefore a proper evaluation should be performed to determine capsular mobility prior to initiating any posterior mobilization efforts . Mobilizations for the posterior capsule are performed parallel to the glenoid fossa in a posterior-lateral direction to increase pliability of the posterior capsule only when true posterior capsular tightness is present (Figure 4).
In addition, Kibler  and Beckett et al  have reported an association between scapular dyskinesis and hip abduction weakness.
Recently, Beckett et al  assessed scapular position and hip strength in preadolescent and adolescent baseball players. The investigators reported a higher rate of scapular dyskinesis in the adolescent group compared with the preadolescent group and poor outcomes of single-leg squat tests. During the physical examination, we recommend that the patient perform a single-leg squat test and that the movement be compared bilaterally (Figure 5). The clinician should assess for any excessive lateral trunk displacement, valgus knee collapse, excessive hip flexion, lateral dropping of the pelvis, and lower extremity pain or dysfunction during the movement. Hip girdle weakness can be treated with lower extremity exercises discussed in this article and neuromuscular control activities to improve scapular kinesis and proprioception.
We believe that hips, core, and scapular exercises are critical to the successful treatment of the throwing athlete (especially young baseball players). During this early phase of rehabilitation, strengthening exercises are initiated with the intention of restoring muscle balance and impeding any further muscle atrophy [27,28]. The clinician may opt to initiate isometrics during this acute phase in the presence of excessive pain and/or soreness and progress to isotonics as tolerated. The aim of exercises in this phase is to reestablish dynamic stability; therefore, the initial focus is on the innately weak posterior rotator cuff and supraspinatus musculature [27,28]. Rhythmic stabilization (RS) exercises are also performed, beginning with Macrotrauma of the glenohumeral joint, and thus the rehabilitation specialist should initiate techniques to heighten the sensory awareness of the afferent mechanoreceptors during this phase of rehabilitation [59,60].
Proprioception and enhanced functional throwing performance test scores have been shown to improve after a 5-week neuromuscular and proprioceptive neuromuscular facilitation (PNF) training program that challenges the glenohumeral musculature [61,62]. RS drills discussed previously and D2 flexion/extension PNF movement patterns are performed to augment proprioception and dynamic stability of the shoulder [20,27,28,59,60,63]. Joint congruency is enhanced by facilitation of agonist and antagonist muscles in restoring a balance in the force couples of the shoulder joint complex . Joint position reproduction drills and upper extremity axial loading exercises such as weight shifts, weight shifts on a ball, wall push-ups, and quadruped drills are performed to stimulate the articular mechanoreceptors and aid in training proprioception during the early stage of treatment [27,65,66].
Effective transfer of kinetic energy from the lower body to the upper extremity, which is vital during throwing, requires adequate mobility, stability, and strength of the legs, hips, and trunk. Core and hip complex exercises are used in this phase for postural reeducation, stability, and mobility of the trunk.
Rehabilitation of the overhead throwing athlete: phases and goals
Phase 1: Acute Phase
-Diminish pain and inflammation
-Delay muscular atrophy
-Re-establish dynamic stability (muscular balance)
-Control functional stress/strain
-Exercises and modalities
-Cryotherapy, iontophoresis, ultrasound, electrical stimulation
-Flexibility and stretching for posterior shoulder muscles to improve shoulder internal rotation and horizontal adduction
-Rotator cuff strengthening (especially external rotator muscles)
-Scapular muscles strengthening (especially retractor and depressor muscles)
-Dynamic stabilization exercises (rhythmic stabilization)
-Abstain from throwing
We’ll discuss Phase 2 soon