Glenohumeral range of motion and stiffness in professional baseball pitchers

PURPOSE: This study was conducted to perform kinematic measures in a group of asymptomatic professional baseball pitchers to determine side-to-side differences in passive glenohumeral range of motion (ROM) and stiffness. We hypothesized that the throwing shoulder in asymptomatic pitchers would display greater passive glenohumeral stiffness than the contralateral nonthrowing shoulder. METHODS: Thirty-four professional baseball pitchers had bilateral assessments for passive glenohumeral ROM and stiffness during a single test session. ROM and stiffness measures were obtained objectively using standard goniometry and instrumented stress arthrometry, respectively. RESULTS: The throwing shoulder had significantly less (-8.5 degrees) internal rotation and significantly more external rotation (5.1 degrees) than the nonthrowing shoulder (P < 0.01). Passive joint stiffness was not significantly different between the throwing and nonthrowing shoulder, and anterior joint stiffness was significantly greater than posterior joint stiffness for both shoulders (P < 0.05). CONCLUSIONS: The repetitive stress of long-term throwing creates altered glenohumeral rotational patterns in the throwing shoulder of the professional baseball pitcher without compromising the joint's passive restraining quality.     

Osseous adaptation and range of motion at the glenohumeral joint in professional baseball pitchers.

The throwing shoulder in pitchers frequently exhibits a paradox of glenohumeral joint motion, in which excessive external rotation is present at the expense of decreased internal rotation. The object of this study was to determine the role of humeral head retroversion in relation to increased glenohumeral external rotation. Glenohumeral joint range of motion and laxity along with humeral head and glenoid version of the dominant versus nondominant shoulders were studied in 25 professional pitchers and 25 nonthrowing subjects. Each subject underwent a computed tomography scan to determine bilateral humeral head and glenoid version. The throwing group demonstrated a significant increase in the dominant shoulder versus the nondominant shoulder in humeral head retroversion, glenoid retroversion, external rotation at 90 degrees, and external rotation in the scapular plane. Internal rotation was decreased in the dominant shoulder. Total range of motion, anterior glenohumeral laxity, and posterior glenohumeral laxity were found to be equal bilaterally. The nonthrowing group demonstrated no significant difference in humeral head retroversion, glenoid retroversion, external rotation at 90 degrees or external rotation in the scapular plane between shoulders, and no difference in internal rotation at 90 degrees, total motion, or laxity. A comparison of the dominant shoulders of the two groups indicated that both external rotation at 90 degrees and humeral head retroversion were significantly greater in the throwing group.     

Magnetic resonance imaging of the shoulder in asymptomatic professional baseball pitchers.

The purpose of this study was to evaluate the magnetic resonance imaging findings in both shoulders of asymptomatic professional baseball pitchers. Fourteen pitchers who were without significant prior injury underwent a blinded clinical assessment and magnetic resonance imaging of both shoulders. All images were interpreted by two experienced musculoskeletal radiologists. The appearance of the rotator cuff tendons was graded, with additional evaluation of the biceps, labrum, and osseous structures. Ten athletes were found to have stable shoulders and painless full range of motion. Clinically, four athletes had at least a 40 degrees loss in internal rotation as compared with the nonthrowing arm. There were no significant differences in magnetic resonance imaging findings of the supraspinatus and infraspinatus tendons between the throwing and nonthrowing shoulders. The labrum was abnormal in 79% of the 28 shoulders. Enthesopathic changes of the posterior glenoid labrum were identified in the four pitchers who had loss of internal rotation. We conclude that unenhanced magnetic resonance imaging of the shoulder in asymptomatic high performance throwing athletes reveals abnormalities that may encompass a spectrum of "nonclinical" findings. These data can be useful in separating symptomatic pathologic findings from these variants. Enthesopathic changes of the posterior glenoid labrum in the throwing arm may represent an early Bennett-type lesion. The cause may be excessive traction on the posterior capsule during the pitching motion, with subclinical injury to this area.     

Quantitative assessment of glenohumeral translation in baseball players: a comparison of pitchers versus nonpitching athletes

BACKGROUND: Objective data quantifying differences in glenohumeral range of motion in baseball pitchers versus position players are established. There is limited information objectively comparing glenohumeral laxity in this same population. HYPOTHESIS: Baseball pitchers have greater difference in side-to-side anteroposterior translation of their throwing shoulders compared with position players. STUDY DESIGN: Prospective cross-sectional study. METHODS: Cutaneous electromagnetic sensors quantified anteroposterior shoulder translation of college and professional baseball players. Range of motion was measured. RESULTS: Nineteen position players and 37 pitchers were studied. Pitchers had a significant increase in external rotation of the dominant arm as compared with the nondominant arm (P = .02); the difference was not significant in position players (P = .34). The mean range of motion for pitchers' dominant arm was 110 degrees external rotation to 68 degrees internal rotation, and it was 100 degrees external rotation to 85 degrees internal rotation for position players (P = .278). The mean anteroposterior translation in pitchers' dominant arm was 33.30 mm and 29.84 mm in the nondominant side (P = .0001). This difference was not present in position players (P = .88). One of 19 position players had a side-to-side shoulder translation difference greater than 3 mm, compared with 22 of 37 pitchers (P = .0001). CONCLUSIONS: Pitchers have a greater amount of glenohumeral translation in the dominant arm. This difference is not seen in position players. These differences make the side-to-side comparison less useful in pitchers and should be considered when making therapeutic decisions.     

Shoulder range of motion characteristics in collegiate baseball players.

BACKGROUND: To determine range of motion and capsular characteristics of dominant and nondominant shoulders in baseball players. Our hypothesis was that there is a significant difference between dominant and nondominant range of motion in collegiate baseball players with unoperated and without shoulder pain. METHODS: Design: prospective, range of motion measurements during regular season. Setting: two collegiate baseball teams in Houston. Participants: 15 pitchers and 23 position players. Main outcome measures: shoulder range of motion was evaluated by goniometric technique in all baseball players. Horizontal adduction (cross body reach test) and active internal rotation (reach behind back) in standing position and external rotation and internal rotation in supine lying position were measured for each player. RESULTS: Average external rotation with the arm in 90 degrees of abduction was significantly greater and average internal rotation was less in the dominant shoulder than in the nondominant shoulders, both in pitchers and position players. There was no statistical difference in shoulder horizontal adduction. Both dominant and nondominant shoulders of pitchers had greater average range of motion in horizontal adduction and external rotation at 90 degrees of abduction and less average internal rotation than those of position players. Although there was a significant difference in active internal rotation as cm between dominant and nondominant shoulders both in both groups, no difference was found between pitchers and position players. CONCLUSIONS: Differences in the range of motion in the throwing shoulder of baseball players exist involved in overhead throwing motions and should be considered in rehabilitation of the upper extremity after injury and in the prevention of injury for pitchers and position players.     

Rotational motion changes in the glenohumeral joint of the adolescent/Little League baseball player

BACKGROUND: Differences in range of motion and rotational motion between the dominant and nondominant shoulders in throwing athletes are well documented, although the age at which these changes begin to occur is not known. HYPOTHESIS: Changes in glenohumeral rotational motion in the shoulder of the Little League/adolescent baseball player occur during the most formative years of physical development. STUDY DESIGN: Cross-sectional study. METHODS: Elevation, internal rotation at 90 degrees of abduction, and external rotation at 90 degrees of abduction were measured in the dominant and nondominant shoulders of 294 baseball players, aged 8 to 16 years. RESULTS: Analysis of variance revealed 2-way interactions between arm dominance by age for elevation (P = .005) and internal rotation (P = .001). Significant differences were noted between dominant and nondominant arms for internal rotation at 90 degrees (P = .001) and external rotation at 90 degrees (P = .001). Elevation, internal rotation at 90 degrees , external rotation at 90 degrees , and total range of motion varied significantly (P = .001) among age groups. Elevation in the dominant arms of 16-year-olds was on average 5.3 degrees less than in 8-year-olds (179.6 degrees vs 174.3 degrees ). In the nondominant arms, mean elevation for 16-year-olds was 5.6 degrees less than in 8-year-olds (179.7 degrees vs 174.1 degrees ). Internal rotation at 90 degrees for the dominant arms averaged 39.0 degrees at age 8 and only 21.3 degrees at age 16. In the non-dominant arms, internal rotation for 8-year-olds averaged 42.2 degrees and only 33.1 degrees for 16-year-olds. CONCLUSIONS: Elevation and total range of motion decreased as age increased. These changes may be consequences of both bone and soft tissue adaptation. The most dramatic decline in total range of motion was seen between the 13-year-olds and 14-year-olds, in the year before peak incidence of Little Leaguer's shoulder. This decrease in rotational motion may cause increased stress at the physis during throwing.     

Glenohumeral joint total rotation range of motion in elite tennis players and baseball pitchers

The amount of glenohumeral joint internal and external rotation used during overhead sport activities has been measured experimentally by sports scientists. Clinical measurement of glenohumeral joint internal and external rotation using goniometry is an integral part of a shoulder evaluation after injury or surgery or during preseason or preventative musculoskeletal screenings. PURPOSE: This study measured glenohumeral joint internal and external rotation in two groups of unilaterally dominant upper extremity athletes to compare the total arc of rotational range of motion between the dominant and nondominant extremities. METHODS: A total of 163 elite athletes (117 male junior tennis players and 46 male baseball pitchers) were measured for glenohumeral joint internal and external rotation at 90 degrees of abduction. Total rotation range of motion was calculated by summing internal and external rotation measures in each extremity. RESULTS: An ANOVA with post hoc testing revealed no significant difference (P > 0.05) between extremities in baseball pitchers for total rotation range of motion (145.7 vs 146.9), whereas significantly less (P < 0.001) dominant arm total rotation range of motion was identified in the elite junior tennis players (149.1 vs 158.2).CONCLUSION: This study has identified unique glenohumeral joint rotational patterning in unilaterally dominant upper extremity athletes that has ramifications for rehabilitation after injury and for both injury prevention and performance enhancement.     

Shoulder rotational properties of throwing athletes

Throwing arm injuries are common and often related to the shoulder external and internal rotation. Quantitative assessment may provide new insights to physical assessment and options for treatment. After having signed IRB approved consents and filled out injury questionnaires, 96 baseball pitchers were examined on both shoulders using a custom-made wireless device. The resistance onset angle (ROA), end-point angle (EPA), shoulder rotational flexibility (SRF) in both external and internal rotation, and rotational ranges of motion (ROM) of both shoulders were determined. About 34% of subjects had surgeries on their throwing arm. Another 15% of subjects had throwing arm injuries that did not require surgical treatments. The throwing arm had significantly lower internal ROA, EPA and SRF, but significantly higher external ROA, EPA and SRF than the non-throwing arm. There were significant differences in shoulder rotational properties among groups with different surgery locations. Subjects with shoulder surgeries had greater internal rotation flexibility of their throwing arm than those with surgeries on the elbow. Throwers with injury and surgery history had significantly different shoulder rotational properties. Abnormal shoulder rotational properties may be related to throwing arm injuries. A better understanding of their relationship may lead us to effective preventive measures of throwing arm injuries.     

Glenohumeral internal rotation deficits in professional pitchers enrolled in an internal rotation stretching program

BACKGROUND: Repetitive throwing motion creates increased external rotation and decreased internal rotation in the glenohumeral joint. There is controversy regarding the contribution of osseous and soft tissue adaptations to these changes in rotation. OBJECTIVE: To evaluate internal rotation deficits in the professional baseball thrower's shoulder and determine the impact of an internal rotation stretch program on that deficit. STUDY DESIGN: Cross-sectional study; Level of evidence, 3. METHODS: Eighty-five male professional pitchers were evaluated in this study. Players were divided into 2 groups based on length of participation in an appropriate internal rotation stretch program. Data were collected on internal and external rotations and total range of motion in both dominant and nondominant arms using a goniometer. Internal rotation deficit (the lack of internal rotation relative to the opposite side) was calculated. Generalized comparative statistical tests were used. RESULTS: Pitchers with 3 or more years in a stretch program (group 1) had greater internal rotation (74.3 degrees vs 54.3 degrees ) and greater total range of motion (217.0 degrees vs 194.2 degrees ) in dominant shoulders than did pitchers with less than 3 years (group 2). Total range of motion was greater in the dominant than in the nondominant arm for group 1. Internal rotation deficit in dominant arms was significantly greater for group 2 than for group 1. The analysis of dominant arm rotation relative to years in an internal rotation stretching program for pitchers in both groups showed a progressive increase in both internal rotation and total arc of motion with the number years in such a program plateauing after year 3. CONCLUSION: The throwing motion shifts the total arc of motion toward external rotation and diminishes internal rotation. The increased external rotation may be attributable to increased humeral retroversion. The internal rotation deficit, however, is caused by soft tissue adaptations that can be addressed by consistent participation in a stretching program focused on internal rotation.     

Rehabilitation of the pitching shoulder

Shoulder pain is a common complaint among baseball pitchers. Frequently, the nature of shoulder pathology can be traced to lack of flexibility and muscular imbalance. This paper describes: the normal biomechanics of a properly functioning shoulder during a baseball pitch, pathomechanics of shoulder problems, flexibility requirements of the throwing shoulder, and the muscular balance necessary for an effective throwing shoulder. Appropriate examination procedures are described along with remedial exercises which ensure normal glenohumeral motion and integrated muscle action.     

Assessment of shoulder proprioception in the female softball athlete

BACKGROUND: There have been reports of overhand throwing athletes having decreased joint position sense in their dominant shoulder as compared with the nondominant shoulder. Very little research, however, exists concerning joint position sense in the female athlete. HYPOTHESIS: Female softball athletes have decreased joint position sense in their dominant shoulder as compared with their nondominant shoulder. STUDY DESIGN: Factorial design with investigation of multiple independent variables. METHODS: Joint position sense was assessed in 50 female softball players and 50 nonthrowing female athletes by using an inclinometer during four glenohumeral joint motions. Both the dominant and nondominant shoulders were assessed and error scores were calculated to describe joint position sense. Data were collected during the course of a fall semester and analyzed by using a mixed model analysis of variance with repeated measures on the dependent variable (error scores). RESULTS: A significant group by movement interaction was observed, with the softball athletes demonstrating significantly greater external rotation error scores than the nonthrowing athletes. CONCLUSION: We failed to reject the null hypothesis. Increased error scores (less joint position sense) were observed in both arms of subjects in the softball group. Clinical Relevance: This study suggests that there is decreased shoulder proprioception in asymptomatic female athletes involved in overyhand throwing sports, which may predispose them to injury.     

Shoulder rotation characteristics in professional tennis players

Aim of this study was to assess the glenohumeral joint internal and external rotational range of motion using an ultrasound based kinematic measurement device. Twenty-seven male professional tennis players were bilaterally measured for internal and external rotation at 90 degrees of shoulder abduction while avoiding scapulothoracic motion. The control group consisted of 20 asymptomatic volunteers not involved in overhead sports activities. The dominant arm (playing arm) had a significantly greater range of external rotation than the non-dominant arm, while their internal rotation showed a significant deficit as compared to the non-dominant arm. The dominant arm total rotational range of motion was also significantly reduced in comparison to the non-dominant arm and to the controls. No significant difference was found between the dominant and non-dominant extremity in the control group. For objective measurement of glenohumeral rotational range of motion ultrasound based real time motion analysis is a new application for the diagnostic testing of specific shoulder parameters in orthopedics and sports physical therapy. It is therefore concluded that the specific methodology aiming at isolated glenohumeral motion may have clinical application for the development of rehabilitation and preventative programs.     

Isokinetic evaluation of shoulder rotational strength in high school baseball pitchers

Isokinetic, shoulder rotational strength was evaluated in 26 high school baseball pitchers before the start of spring practice. Using the Cybex II (Cybex, Division of Lumex, Inc., Ronkonkoma, NY), test data were gathered on the dominant and nondominant shoulders in the supine 90 degrees abducted test position (90 degrees AbTP) and the standing neutral test position (neutral TP). Tests were performed at 90 and 240 deg/sec. The HUMAC (Computer Sports Medicine, Inc., Flemington, NJ) computer system was used to analyze data. Means and standard deviations for peak torque, total work, peak torque to body weight ratios, and agonist/antagonist ratios are presented. Comparison of dominant to non-dominant sides and 90 degrees AbTP to neutral TP values are reported. Peak torque and total work values for the throwing side internal rotators were significantly higher than the nonthrowing side in all tests. Pitching side external rotators failed to show this dominance. External/internal rotation ratios for peak torque and total work were significantly lower on the pitching side, suggesting a relative imbalance of cuff musculature compared to the nonpitching shoulder. Significant differences existed between data gathered in the two different test positions. In the 90 degrees AbTP, external rotation peak torque and total work values and external/internal rotation peak torque and total work ratios were higher than the equivalent values gathered in the neutral TP. Internal rotation peak torque and total work values tended to be higher in the neutral TP than in the 90 degrees AbTP.(ABSTRACT TRUNCATED AT 250 WORDS)     

Acute changes in glenohumeral range-of-motion following in-season minor league pitching starts

Background. Asymmetric glenohumeral range-of-motion (ROM) between the throwing and non-throwing arms of overhead athletes has been well described in the literature. Thresholds of internal rotation (IR) loss have been associated with throwing arm injury in baseball players. Acute changes in shoulder ROM following an individual pitching appearance remain poorly understood. Objectives: To determine the acute change of external rotation (ER), IR, and total arc-of-motion (TAM) in minor league starting pitchers immediately following an in-season starting pitching appearance. Methods. Nine minor league starting pitchers participated in the study with data collected for 22 individual starts. IR, ER and TAM were measured in the throwing shoulder and non-throwing shoulder at three time points for each appearance: before, immediately following, and at 24 hours following the pitching appearance. Results. In the throwing arm, IR significantly decreased (49.4 vs 46.0, p = 0.037) immediately after pitching, and ER significantly increased immediately following an appearance (150.7 vs 153.6, p = 0.030) and at 24 hours (150.7 vs 154.0, p = 0.028). No difference was detected in throwing arm TAM and IR at 24 hours, or TAM immediately following an appearance. Conclusions. Minor league pitchers demonstrate the dynamic glenohumeral ROM changes after starting appearances of increased ER and diminished IR with maintenance of TAM. At 24 hours, the observed loss of IR had resolved, whereas the gains in ER remained present. Our study supports the need to further assess the acute changes of glenohumeral ROM in pitchers, and the association of acute glenohumeral ROM change with the development of pathologic ROM profiles and injury.     

Quantitative assessment of glenohumeral translation after anterior shoulder dislocation and subsequent arthroscopic bankart repair

BACKGROUND: During the past decade, developments in arthroscopic technology have made arthroscopic repair of labral lesions feasible. However, results with the use of the transglenoid suture technique, or with the use of bioabsorbable tacks, have remained variable in the literature, and the recurrence rates are still inferior to those of open Bankart repair. HYPOTHESIS: Arthroscopic Bankart repair with suture anchors can re-create translational and rotational range of motion of the intact glenohumeral joint, and the number of preoperative dislocations has an influence on the result. STUDY DESIGN: Controlled laboratory study. MATERIALS: Twelve cadaveric shoulders were tested in a robot-assisted shoulder simulator. Anterior and posterior translation and external rotation were measured for intact, dislocated (shoulders were randomly selected to 1 of 3 groups, which were dislocated 1, 3, or 7 times), and repaired conditions at 0 degrees and 90 degrees of glenohumeral elevation. RESULTS: After shoulder dislocation, a significant increase was found in translation and rotation, confirming the creation of a traumatic shoulder instability model. Further testing of the specimen revealed that translational and rotational ranges of motion were reduced by arthroscopic Bankart repair at both testing positions. External rotation was decreased significantly at 0 degrees and 90 degrees of abduction. No significant differences were found between the 3 dislocation groups. CONCLUSION: The results demonstrate a sufficient biomechanical performance of arthroscopic Bankart repair using suture anchors in a traumatic anterior shoulder instability model. With the numbers available, no relationship was found between the number of dislocations and the postoperative result concerning translational or rotational motion. CLINICAL RELEVANCE: Glenohumeral translation and rotation after arthroscopic Bankart repair with use of suture anchors approached near normal values, confirming the clinical success of this technique.     

Beweglichkeit der Wurfarmschulter sowie isometrische Kraftentwicklung und ihre Veränderungen unter Trainings- und Saisonbedingungen beim semi- /professionellen Handballsportler Teil I: Veränderungen in der Saisonvorbereitungsphase

The rotational capacity of the throwing shoulder and their changes during the pre-season and season in semi- and professional team handball athletes is not very much investigated yet. There are no data on changes in isometric strength as well, but correlations between the overhead- and throwing athlete shoulder, their changes in the rotational capacity and a risk of structural joint damages and symptoms.Materials and MethodsIn a longitudinal intra-individual investigation 27 semi- and professional male, third league team handball athletes underwent a specific clinical shoulder examination and were examined at the beginning (MZP 1) and end (MZP 2) of the pre-seasonal training (VP) at the dominant (throwing) and non dominant (non throwing) shoulder according to rotational strength (isometric) and range of motion.ResultsThe internal rotation (IR) at the dominant throwing shoulder (WA) was significantly reduced in comparison to the non throwing shoulder (NWA) at both days of determinations (baseline, after 6 weeks). The external rotation (ER) at the WA was significantly greater than the ER at the NWA at both times. The total range of motion (tROM) and the GIRD was slightly, but not significantly reduced at the WA at the end of the VP. The external rotational gain (ERG) was significantly reduced during the VP. The isometric strength in IR and ER at the WA was larger in comparison to the NWA at baseline. During the VP a significant reduction in internal rotational (IR) and isometric strength was seen at the WA. The external rotational isometric strength (ER) significantly reduced as well over the period of time at the WA.ConclusionsOver the period of 6 weeks the pre-seasonal training in team handball did not lead to significant pathological changes of the rotational capacities in shoulder joints, even not in a glenohumeral internal rotation deficit. The external rotation gain did significantly reduce after the period of the pre-seasonal training. The isometric strength in internal and external rotational movement also decreased significantly. Our data more likely show adaptive processes at the throwing shoulder joint according to the workload during training.Level of EvidenceLevel III.