Kevin G. Laudner

Glenohumeral Range of Motion Deficits and Posterior Shoulder Tightness in Throwers With Pathologic Internal Impingement

Background Alterations in glenohumeral range of motion, including increased posterior shoulder tightness and glenohumeral internal rotation deficit that exceeds the accompanying external rotation gain, are suggested contributors to throwing-related shoulder injuries such as pathologic internal impingement. Yet these contributors have not been identified in throwers with internal impingement. Hypothesis Throwers with pathologic internal impingement will exhibit significantly increased posterior shoulder tightness and glenohumeral internal rotation deficit without significantly increased external rotation gain. Study Design Case control study; Level of evidence, 3. Methods Eleven throwing athletes with pathologic internal impingement diagnosed using both clinical examination and a magnetic resonance arthrogram were demographically matched with 11 control throwers who had no history of upper extremity injury. Passive glenohumeral internal and external rotation were measured bilaterally with standard goniometry at 90 ° of humeral abduction and elbow flexion. Bilateral differences in glenohumeral range of motion were used to calculate glenohumeral internal rotation deficit and external rotation gain. Posterior shoulder tightness was quantified as the bilateral difference in passive shoulder horizontal adduction with the scapula retracted and the shoulder at 90 ° of elevation. Comparisons were made between groups with dependent t-tests (P< .05). Results The throwing athletes with internal impingement demonstrated signif icantly greater glenohumeral internal rotation deficit (P= .03) and posterior shoulder tightness (P= .03) compared with the control subjects. No significant differences were observed in external rotation gain between groups (P= .16). Clinical Relevance These findings could indicate that a tightening of the posterior elements of the shoulder (capsule, rotator cuff) may contribute to impingement. The results suggest that management should include stretching to restore flexibility to the posterior shoulder.

Scapular Position and Orientation in Throwing Athletes

Background Despite the recognized importance of proper 3-dimensional motion of the scapula in throwers, minimal research has quantified scapular position and orientation in throwing athletes. Hypothesis Throwing athletes exhibit scapular position and orientation differences when compared to nonthrowing control subjects. Study Design Descriptive laboratory study. Methods Scapular position and orientation during scapular plane humeral elevation were assessed with electromagnetic tracking in a group of 21 throwing athletes and 21 control subjects. Scapular upward/downward rotation, internal/external rotation, anterior/posterior tipping, elevation/depression, and protraction/retraction were assessed. Results The throwing athletes demonstrated significantly increased upward rotation, internal rotation, and retraction of the scapula during humeral elevation. No differences in anterior/posterior tipping and elevation/depression were present. Conclusions The results indicate that throwing athletes have scapular position and orientation differences compared to nonthrowing athletes. This suggests that throwers develop chronic adaptation for more efficient performance of the throwing motion. Clinical Relevance Clinicians evaluate scapular position, orientation, and movement in throwing athletes as part of the evaluation of shoulder injuries associated with the throwing motion. The current study provides clinicians with an understanding of the types of adaptations that may be observed in normal, healthy throwing athletes.

Mobility and Stability Adaptations in the Shoulder of the Overhead Athlete A Theoretical and Evidence-Based Perspective

Overhead athletes require a delicate balance of shoulder mobility and stability in order to meet the functional demands of their respective sport. Altered shoulder mobility has been reported in overhead athletes and is thought to develop secondary to adaptive structural changes to the joint resulting from the extreme physiological demands of overhead activity. Researchers have speculated as to whether these structural adaptations compromise shoulder stability, thus exposing the overhead athlete to shoulder injury. Debate continues as to whether these altered mobility patterns arise from soft-tissue or osseous adaptations within and around the shoulder. Researchers have used quantitative techniques in an attempt to better characterize these structural adaptations in the shoulders of overhead athletes. Throwing athletes have been shown to display altered rotational range of motion (ROM) patterns in the dominant shoulder that favour increased external rotation and limited internal rotation ROM. Throwers also show a loss of horizontal or cross-body adduction in the throwing shoulder when compared with the non-throwing shoulder. This posterior shoulder immobility in the throwing shoulder is thought by some researchers to be associated with reactive scarring or contracture of the periscapular soft-tissue structures (e.g. posterior capsule and/or cuff musculature); however, evidence of reactive scarring or contractures of the posterior-inferior capsule or cuff musculature from anatomic or noninvasive imaging studies is lacking. Conversely, translational ROM (laxity) has been consistently shown to be symmetric between dominant and non-dominant shoulders of overhead athletes.From a skeletal perspective, throwing shoulders are shown to have more humeral retroversion when compared with the non-throwing shoulder. Alterations in humeral retroversion are thought to develop over time in young pre-adolescent throwers when the proximal humeral epiphysis is not yet completely fused. Even though the evidence is inconclusive at the present time, there is more compelling evidence that leads us to believe that altered shoulder mobility in the overhead-throwing athlete is more strongly associated with adaptive changes in proximal humeral anatomy (i.e. retroversion) than to structural changes in the articular and periarticular soft tissue structures. In addition, this retroversion is thought to account for the observed shift in the arc of rotational ROM in overhead athletes. However, in some athletes, capsulo-ligamentous adaptations such as anterior-inferior stretching or posterior-inferior contracture may become superimposed upon the osseous changes. This may ultimately lead to pathological manifestations such as secondary impingement, type II superior labrum from anterior to posterior (SLAP) lesions and/or internal (glenoid) impingement.Overuse injuries in the overhead athlete are a common and perplexing clinical problem in sports medicine and, therefore, it is imperative for sports medicine clinicians to have a thorough understanding of the short- and long-term effects of overhead activity on the shoulder complex. It is our intention that the information presented will serve as a guide for clinicians who treat the shoulders of overhead athletes.

The immediate effects of muscle energy technique on posterior shoulder tightness: a randomized controlled trial.

STUDY DESIGN Randomized controlled trial. OBJECTIVES To compare a muscle energy technique (MET) for the glenohumeral joint (GHJ) horizontal abductors and an MET for the GHJ external rotators to improve GHJ range of motion (ROM) in baseball players. BACKGROUND Overhead athletes often exhibit loss of GHJ ROM in internal rotation, which has been associated with shoulder pathology. Current stretching protocols aimed at improving flexibility of the posterior shoulder have resulted in inconsistent outcomes. Although utilization of MET has been hypothesized to lengthen tissue, there are limited empirical data describing the effectiveness of such stretches for treating posterior shoulder tightness. METHODS Sixty-one Division I baseball players were randomly assigned to 1 of 3 groups: MET for the GHJ horizontal abductors (n = 19), MET for the GHJ external rotators (n = 22), and control (n = 20). We measured preintervention and postintervention GHJ horizontal adduction and internal rotation ROM, and conducted analyses of covariance, followed by Tukey honestly significant difference post hoc analysis for significant group-by-time interactions (P<.05). RESULTS The group treated with the MET for the horizontal abductors had a significantly greater increase in GHJ horizontal adduction ROM postintervention (mean ± SD, 6.8° ± 10.5°) compared to the control group (-1.1° ± 6.8°) (P = .011) and a greater increase in internal rotation ROM postintervention (4.2° ± 5.3°) compared to the group treated with the MET for the external rotators (0.2° ± 6.3°) (P = .020) and the control group (-0.2° ± 4.0°) (P = .029). No significant differences among groups were found for any other variables (P>.05). CONCLUSION A single application of an MET for the GHJ horizontal abductors provides immediate improvements in both GHJ horizontal adduction and internal rotation ROM in asymptomatic collegiate baseball players. Application of MET for the horizontal abductors may be useful to gain ROM in overhead athletes. LEVEL OF EVIDENCE Therapy, level 2b-.

Functional Hip Characteristics of Baseball Pitchers and Position Players

Background During the throwing motion, the lower extremity is responsible for creating power that is transmitted through the core to the upper extremity. Research has shown that good hip range of motion and strength in throwing athletes results in greater performance and decreased stress placed on the upper extremity. Although research has investigated bilateral differences in hip characteristics among baseball pitchers, little is known about differences between pitchers and position players. Hypothesis Pitchers will have decreased passive hip rotation range of motion and gluteus medius strength compared with position players. Study Design Cross-sectional study; Level of evidence, 3. Methods Forty professional baseball pitchers and 40 position players with no recent history of lower extremity injury participated. Bilateral hip external and internal rotation range of motion, total arc of motion, and gluteus medius strength were measured with a digital inclinometer and handheld dynamometer. Results A Hotelling T2 multivariate analysis of variance showed position players to have significantly more hip internal rotation range of motion (3.1°, P = .01, effect size = .53) and abduction strength (3.5 kg, P =.04, effect size = .53) in the trail leg compared with the pitchers. There were no significant differences for any other hip characteristics between groups (P > .07). Conclusion The results of this study indicate that baseball pitchers have significantly smaller amounts of hip internal rotation range of motion and abduction strength of the trail leg compared with position players. However, these differences may not be clinically significant. Clinical Relevance Position players may be able to develop more energy in the lower extremity, while pitchers may rely more on energy created in the core and upper extremity, potentially placing pitchers at an increased risk for upper extremity injury. These descriptive hip characteristics may help clinicians detect inadequacies and provide appropriate prevention, diagnostic, and treatment interventions for such athletes.

The Relationship Between Forward Scapular Posture and Posterior Shoulder Tightness Among Baseball Players

Background Excessive and untimely scapular dyskinesis during the throwing motion has been associated with several shoulder injuries. The scapula provides attachment for many soft tissue structures. Therefore, many have hypothesized that posterior shoulder tightness may alter proper scapular kinematics. Hypothesis As posterior shoulder tightness increases, so will forward scapular posture. Baseball players will have a significantly more forward scapular position of their dominant arm compared with their nondominant arm. The bilateral difference in forward scapular posture will be greater in pitchers than in position players, indicating pitchers have more forward scapular posture. Study Design Cross-sectional study; Level of evidence, 3. Methods Bilateral forward scapular posture, glenohumeral horizontal adduction, and rotational range of motion were measured among 20 professional baseball pitchers and 20 position players. Results A regression analysis showed a moderate to good negative relationship between glenohumeral horizontal adduction range of motion and forward scapular posture (r2 = .50, P = .001). T tests demonstrated that the dominant shoulders of both groups had significantly more forward scapular posture compared with nondominant shoulders (P < .004). There were no other significant relationships or differences found (r2 < .04, P > .15). Conclusion There was a moderate to good relationship between posterior shoulder tightness and forward scapular posture. Furthermore, baseball players had more forward scapular posture of the dominant arm than the nondominant arm. These results suggest that posterior shoulder tightness as evidenced by decreased glenohumeral adduction range of motion may be considered a partial predictor for excessive forward scapular posture and vice versa. Because of the association between this scapular dyskinesis and shoulder dysfunction, clinicians may find it advantageous to address these characteristics when examining and treating such athletes.

Differences in Scapular Upward Rotation Between Baseball Pitchers and Position Players

Background Baseball pitchers have been reported to have an increased prevalence of shoulder injury compared with position players such as infielders and outfielders. Furthermore, insufficient scapular upward rotation has been empirically linked with several of these shoulder disorders. However, the difference in scapular upward rotation between pitchers and position players is not known. Hypothesis Pitchers will have decreased scapular upward rotation of their dominant shoulders compared with position players. Study Design Descriptive laboratory study. Methods Dominant shoulder scapular upward rotation was measured with the arm at rest and at 60°, 90°, and 120° of humeral elevation among 15 professional baseball pitchers and 15 position players with no recent history of upper extremity injury. Results Independent t tests showed pitchers have significantly less scapular upward rotation at 60° (3.9°, P = .011) and 90° (4.4°, P = .009) of humeral elevation compared with position players. Conclusion Baseball pitchers have less scapular upward rotation than do position players, specifically at humeral elevation angles of 60° and 90°. Clinical Relevance This decrease in scapular upward rotation may compromise the integrity of the glenohumeral joint and place pitchers at an increased risk of developing shoulder injuries compared with position players. As such, pitchers may benefit from periscapular stretching and strengthening exercises to assist with increasing scapular upward rotation.

Neuromuscular and Biomechanical Adaptations of Patients with Isolated Deficiency of the Posterior Cruciate Ligament

Background Functional adaptations of patients with posterior cruciate ligament deficiency (grade II) are largely unknown despite increased recognition of this injury. Hypothesis Posterior cruciate ligament-deficient subjects (grade II, 6- to 10-mm bilateral difference in posterior translation) will present with neuromuscular and biomechanical adaptations to overcome significant mechanical instability during gait and drop-landing tasks. Study Design Controlled laboratory study. Methods Bilateral comparisons were made among 10 posterior cruciate ligament-deficient subjects using radiographic, instrumented laxity, and range of motion examinations. Biomechanical and neuromuscular characteristics of the involved limb of the posterior cruciate ligament-deficient subjects were compared to their uninvolved limb and to 10 matched control subjects performing gait and drop-landing tasks. Results Radiographic (15.3 ± 2.9 to 5.6 ± 3.7 mm; P =. 008) and instrumented laxity (6.3 ± 2.0 to 1.4 ± 0.5 mm; P <. 001) examinations demonstrated significantly greater posterior displacement of the involved knee within the posterior cruciate ligament-deficient group. The posterior cruciate ligament-deficient group had a significantly decreased maximum knee valgus moment and greater vertical ground reaction force at midstance during gait compared to the control group. During vertical landings, the posterior cruciate ligament-deficient group demonstrated a significantly decreased vertical ground reaction force loading rate. All other analyses reported no significant differences within or between groups. Conclusion Posterior cruciate ligament-deficient subjects demonstrate minimal biomechanical and neuromuscular differences despite significant clinical laxity. Clinical Relevance The findings of this study indicate that individuals with grade II posterior cruciate ligament injuries are able to perform gait and drop-landing activities similar to a control group without surgical intervention.

The relationship between clinically measured hip rotational motion and shoulder biomechanics during the pitching motion

OBJECTIVES To examine how clinically measured hip motion is related to shoulder biomechanics during the pitching motion. DESIGN Cross-sectional. METHODS Bilateral hip rotational range of motion was measured clinically among 34 collegiate baseball pitchers. External rotation torque and maximum horizontal adduction range of motion of the throwing shoulder were measured using a three-dimensional, high speed video capture system. RESULTS Separate standard multiple regression analyses showed that the total hip rotational range of motion of the lead leg had a significant relationship with shoulder external rotation torque during the throwing motion (r=0.56, P=0.003). Both lead leg hip external rotation range of motion (r=-0.39, P=0.02) and internal rotation range of motion (r=0.42, P=0.009) made significant contributions to this dependent variable. Lead leg external rotation range of motion also had a significant negative relationship with shoulder horizontal adduction range of motion (r=-0.36, P=0.04). The total rotational range of motion of the trail leg had a significant relationship with shoulder horizontal adduction range of motion (r=0.43, P=0.04). However, trail leg external rotation range of motion was the only significant contributor to this relationship (r=-0.35, P=0.04). No other significant relationships were noted (r<0.37, P>0.11). CONCLUSIONS Our results demonstrate that altered hip rotational range of motion, measured clinically, has a direct effect on the amount of external rotation torque and horizontal adduction range of motion of the shoulder during the throwing motion.

Anterior Glenohumeral Laxity Is Associated With Posterior Shoulder Tightness Among Professional Baseball Pitchers

Background: Baseball pitchers often have increased anterior glenohumeral (GH) laxity and posterior shoulder tightness due to large forces produced during the throwing motion. As such, many clinicians have hypothesized that a relationship exists between these common characteristics. Hypothesis: A negative relationship will exist between anterior GH laxity and the summation of GH adduction range of motion (ROM) and GH internal rotation ROM asymmetry. Study Design: Cross-sectional study; Level of evidence, 3. Methods: Anterior GH laxity, GH rotation ROM, and GH horizontal adduction ROM were measured in 58 asymptomatic professional baseball pitchers. Differences in GH internal rotation at 90° of abduction were calculated between both shoulders. A multiple regression analysis was used to determine the strength of the relationships between anterior GH laxity (dependent variable) and GH adduction ROM and GH internal rotation ROM asymmetry (independent variables) (P < .05). Results: A large portion of anterior GH laxity was predicted by the summation of GH adduction ROM and GH internal rotation ROM asymmetry (r2 = .45, P = .001). Furthermore, increased anterior GH laxity had a significant relationship with both decreased GH horizontal adduction ROM (r = .53, P = .001) and differences in GH internal rotation ROM (r = .43, P = .001). Conclusion: The results of this study suggest that decreased GH horizontal adduction and internal rotation ROM may be considered partial predictors for increased anterior GH laxity in the throwing arm of baseball players. Because of the association between these variables, clinicians may find it advantageous to address posterior shoulder tightness during the prevention, diagnosis, and treatment of shoulder injuries associated with anterior GH laxity.