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1.  Glenohumeral Rotational Range of Motion in Collegiate Overhead-Throwing Athletes During an Athletic Season 
Journal of Athletic Training  2009;44(6):611-616.
Abstract
Context:
Repetitive throwing at high velocities leads to altered range of motion (ROM) in the dominant shoulder compared with the nondominant shoulder in overhead-throwing athletes. Loss of glenohumeral internal rotation (IR), or glenohumeral internal-rotation deficit (GIRD), is associated with shoulder injuries. Therefore, GIRD should be evaluated during the clinical examination of the thrower's shoulder.
Objective:
To assess glenohumeral ROM in competitive baseball and softball athletes at 3 intervals over the course of an athletic season in order to (1) examine changes in ROM over time and (2) monitor the prevalence of GIRD.
Design:
Observational, repeated-measures study.
Setting:
Collegiate athletic training room.
Patients or Other Participants:
Forty-eight healthy National Collegiate Athletic Association (NCAA) Division I or Division II athletes (age  =  19 ± 1 years, height  =  174 ± 14 cm, mass  =  77.8 ± 18.1 kg; 19 softball, 29 baseball players).
Main Outcome Measure(s):
We measured glenohumeral IR, external rotation (ER), total arc (ER + IR), and GIRD at 3 times: prefall, prespring, and postspring. We calculated GIRD in 2 ways: as the difference in IR between dominant and nondominant shoulders and as the percentage of the total arc.
Results:
In the dominant shoulder, ER increased during the season (F2,96  =  17.433, P < .001), but IR remained the same (F2,96  =  1.839, P  =  .17). The total arc in the dominant shoulder increased between time intervals (F2,96  =  14.030, P < .001); the mean difference between prefall and postspring measurements was 9.694° (P < .001), and the mean difference between prefall and postspring measurements was 10.990° (P < .001). In the nondominant shoulder, ER increased over the season (F2,96  =  23.395, P < .001), but IR did not change over the season (F2,96  =  0.087, P  =  .90). The total arc in the nondominant shoulder increased between prefall and prespring measurements and between prefall and postspring measurements (F2,96  =  18.552, P < .001). No changes were noted in GIRD over time. However, more athletes with GIRD were identified with the GIRD (IR difference) calculation in prefall (n  =  6) than in prespring (n  =  1) and postspring (n  =  4) (Cochran Q  =  5.2, P  =  .07). In addition, more athletes with GIRD were identified with the GIRD (% total arc) calculation in postspring (n  =  6) than in prefall (n  =  5) or prespring (n  =  4) (Cochran Q  =  2.6, P  =  .27).
Conclusions:
Healthy NCAA Division I and Division II athletes did not display changes in glenohumeral IR over an athletic season. However, they gained in ER and total arc during the season in both shoulders. Future researchers should investigate changes over multiple seasons. The 2 methods of calculating GIRD identified different athletes as having GIRD, indicating that additional investigation is warranted to determine the clinical benefits of each method.
doi:10.4085/1062-6050-44.6.611
PMCID: PMC2775362  PMID: 19911087
shoulder; upper extremity; glenohumeral internal-rotation deficit
2.  The Effects of Repetitive Overhead Throwing on Shoulder Rotator Isokinetic Work-Fatigue. 
Background
Muscle strength and endurance of the shoulder rotators is important for overhead throwing performance and dynamic glenohumeral stability. Baseball pitching is distinguished as an intermittent activity with explosive, high intensity muscle contractions separated by periods of rest. Rotator cuff muscle performance could acutely decrease due to fatigue associated with bouts of throwing.
Objective
This study examined the effects of repeated overhead throwing upon isokinetic muscle performance of the shoulder rotators.
Methods
Repeated-measures analyses of vari-ance were used to compare peak torque, total work, and work-fatigue by muscle group, time, and contraction type. Ten collegiate baseball pitchers underwent isokinetic testing of the internal (IR) and external shoulder (ER) rotators one week before and immediately after a throwing protocol of 60 maximal-effort pitches arranged into four innings of 15 pitches per inning. Isokinetic testing consisted of 12 concentric and eccentric repetitions at 300 deg/sec for internal and external rotation of the throwing extremity.
Results
The main effect of time and the interaction of muscle group and contraction type were significant for work-fatigue. Post-hoc analysis revealed that subjects had significantly greater eccentric IR work-fatigue (13.3 + 1%) compared to the pre-test (7.3 + 2%).
Discussion and Conclusions
Throwing-related fatigue affected both muscle groups, especially the IR, which has implications for dynamic glenohumeral stability. Rehabilitation and conditioning programs for competitive baseball pitchers should emphasize eccentric muscle endurance training of the shoulder rotators.
PMCID: PMC2953290  PMID: 21522204
shoulder; baseball pitching; rotator cuff
3.  GLENOHUMERAL MOTION DEFICITS: FRIEND OR FOE? 
In most shoulder conditions a loss of glenohumeral motion results in shoulder performance impairments. However, in the overhead athlete loss of glenohumeral internal rotation, termed glenohumeral internal rotation deficiency (GIRD), is a normal phenomenon that should be expected. Without a loss of glenohumeral internal rotation the overhead athlete will not have the requisite glenohumeral external rotation needed to throw a baseball at nearly 100 miles per hour, or serve a tennis ball at velocities of 120 miles per hour or more. Not all GIRD is pathologic.
The authors of this manuscript have defined two types of GIRD; one that is normal and one that is pathologic. Anatomical GIRD (aGIRD) is one that is normal in overhead athletes and is characterized by a loss of internal rotation of less than 18°‐20° with symmetrical total rotational motion (TROM) bilaterally. Pathologic GIRD (pGIRD) is when there is a loss of glenohumeral internal rotation greater than 18°‐20° with a corresponding loss of TROM greater than 5° when compared bilaterally. A more problematic motion restriction may be that of a loss of TROM in the glenohumeral joint. Recent evidence supports that a loss of TROM is predictive of future injury to the shoulder in professional athletes. Additionally, external rotation deficiency (ERD), the difference between external rotation (ER) of the throwing shoulder and the non‐throwing shoulder of less than 5°, may be another predictor of future shoulder injury and disability.
Level of Evidence:
5
PMCID: PMC3811728  PMID: 24175137
External rotation deficiency; glenohumeral internal rotation deficit; total rotation motion
4.  ACUTE EFFECTS OF INSTRUMENT ASSISTED SOFT TISSUE MOBILIZATION FOR IMPROVING POSTERIOR SHOULDER RANGE OF MOTION IN COLLEGIATE BASEBALL PLAYERS 
Background:
Due to the repetitive rotational and distractive forces exerted onto the posterior shoulder during the deceleration phase of the overhead throwing motion, limited glenohumeral (GH) range of motion (ROM) is a common trait found among baseball players, making them prone to a wide variety of shoulder injuries. Although utilization of instrument‐assisted soft tissue mobilization (IASTM), such as the Graston® Technique, has proven effective for various injuries and disorders, there is currently no empirical data regarding the effectiveness of this treatment on posterior shoulder tightness.
Purpose:
To determine the effectiveness of IASTM in improving acute passive GH horizontal adduction and internal rotation ROM in collegiate baseball players.
Methods:
Thirty‐five asymptomatic collegiate baseball players were randomly assigned to one of two groups. Seventeen participants received one application of IASTM to the posterior shoulder in between pretest and posttest measurements of passive GH horizontal adduction and internal rotation ROM. The remaining 18 participants did not receive a treatment intervention between tests, serving as the controls. Data were analyzed using separate 2× 2 mixed‐model analysis of variance, with treatment group as the between‐subjects variable and time as the within‐subjects variable.
Results:
A significant group‐by‐time interaction was present for GH horizontal adduction ROM with the IASTM group showing greater improvements in ROM (11.1°) compared to the control group (‐0.12°) (p <0.001). A significant group‐by‐time interaction was also present for GH internal rotation ROM with the IASTM group having greater improvements (4.8°) compared to the control group (‐0.14°) (p < 0.001).
Conclusions:
The results of this study indicate that an application of IASTM to the posterior shoulder provides acute improvements in both GH horizontal adduction ROM and internal rotation ROM among baseball players.
Level of Evidence:
2b
PMCID: PMC3924602  PMID: 24567849
Manual therapy; rehabilitation; shoulder; throwing athlete
5.  Passive Range of Motion Characteristics in the Overhead Baseball Pitcher and Their Implications for Rehabilitation 
Background
Repetitive overhead throwing motion causes motion adaptations at the glenohumeral joint that cause injury, decrease performance, and affect throwing mechanics. It is essential to define the typical range of motion (ROM) exhibited at the glenohumeral joint in the overhead thrower.
Questions/purposes
We (1) assessed the glenohumeral joint passive range of motion (PROM) characteristics in professional baseball pitchers; and (2) applied these findings clinically in a treatment program to restore normal PROM and assist in injury prevention.
Methods
From 2005 to 2010, we evaluated 369 professional baseball pitchers to assess ROM parameters, including bilateral passive shoulder external rotation (ER) at 45° of abduction, external and internal rotation (IR) at 90° abduction while in the scapular plane, and supine horizontal adduction.
Results
The mean ER was greater for the throwing and nonthrowing shoulders at 45° of abduction, 102° and 98°, respectively. The throwing shoulder ER at 90° of abduction was 132° compared with 127° on the nonthrowing shoulder. Also, the pitcher’s dominant IR PROM was 52° compared with 63° on the nondominant side. We found no statistically significant differences in total rotational motion between the sides.
Conclusions
Although we found side-to-side differences for rotational ROM and horizontal adduction, the total rotational ROM was similar.
Clinical Relevance
The clinician can use these PROM values, assessment techniques, and treatment guidelines to accurately examine and develop a treatment program for the overhead-throwing athlete.
doi:10.1007/s11999-012-2265-z
PMCID: PMC3348299  PMID: 22532313
6.  Glenohumeral joint: internal and external rotation range of motion in javelin throwers 
OBJECTIVE: To assess differences in glenohumeral joint rotatory range of movement in javelin throwers between the throwing and non-throwing arm. METHOD: A universal 360 degrees goniometer was used to assess glenohumeral joint external and internal rotation range in 90 degrees of shoulder abduction in a group of ten senior international javelin throwers. RESULTS: Both arms had significantly greater degrees of external than internal rotation (p < 0.01), and the throwing arm had significantly greater range of external rotation than the non-throwing arm (p < 0.01). CONCLUSIONS: The presence of an excessive range of external rotation in the throwing shoulder has the potential to increase eccentric load on the rotator cuff muscles and strain on the passive restraints of the glenohumeral joint. Both of these factors have been implicated in the pathological processes leading to injury in the overhead throwing athlete. 



PMCID: PMC1756107  PMID: 9773171
7.  Associations Among Hip and Shoulder Range of Motion and Shoulder Injury in Professional Baseball Players 
Journal of Athletic Training  2010;45(2):191-197.
Abstract
Context:
The overhead throwing motion is complex, and restrictions in range of motion (ROM) at the hip may place additional demands on the shoulder that lead to injury. However, the relationship between hip and shoulder ROM in athletes with and without a history of shoulder injury is unknown.
Objective:
To (1) determine if differences exist in hip and shoulder ROM between professional baseball players with a history of shoulder injury and those with no history of shoulder injury and (2) assess relationships between hip and shoulder ROM in these players.
Design:
Cross-sectional study.
Patients or Other Participants:
Fifty-seven professional baseball players.
Main Outcome Measure(s):
Outcome measures consisted of hip extension and internal rotation, shoulder internal and external rotation, glenohumeral internal-rotation deficit, and history of shoulder injury. Differences in shoulder and hip ROM were assessed with a 1-way analysis of variance. Associations between hip and shoulder ROM were assessed with linear regression.
Results:
Nonpitchers with a history of shoulder injury had more external rotation and less internal rotation of the shoulder than nonpitchers with no history of shoulder injury. Glenohumeral internal-rotation deficit was greater in both pitchers and nonpitchers with a history of shoulder injury. The relationship between dominant hip extension and shoulder external rotation was significant for pitchers with a history of shoulder injury and nonpitchers with a history of shoulder injury.
Conclusions:
Shoulder injury may be associated with specific measures of hip and shoulder ROM, and hip extension and shoulder external rotation may be related in baseball players with a history of shoulder injury. Additional research is necessary to understand the specific mechanisms of shoulder injury in the throwing athlete.
doi:10.4085/1062-6050-45.2.191
PMCID: PMC2838471  PMID: 20210623
throwing athletes; injuries; glenohumeral internal-rotation deficit; kinetic chain
8.  Glenohumeral Range of Motion in Major League Pitchers 
Sports Health  2011;3(1):97-104.
Background:
Although overhead throwing athletes may develop unique glenohumeral range of motion characteristics, to our knowledge these characteristics have not been studied longitudinally in major league pitchers.
Hypothesis:
Major league pitchers (starters and relievers) experience an increase in glenohumeral external rotation and a decrease in internal rotation and total range of motion. Glenohumeral internal rotation deficit worsens over a regular playing season.
Study Design:
Retrospective cohort study.
Methods:
In 21 major league baseball pitchers (29 individual playing seasons), glenohumeral range of motion was measured in external and internal rotation for the throwing and nonthrowing shoulders before and at the conclusion of the regular season. The total range of motion (the sum of external rotation and internal rotation) and the glenohumeral internal rotation deficit were calculated (the difference between internal rotation of the nonthrowing shoulder minus that of the throwing shoulder), and data were compared between starting and relief pitchers.
Results:
The overall mean changes in external rotation (+1.5°), internal rotation (+2.7°), and total range of motion (+3.3°) were not statistically significant. However, starting pitchers showed statistically significant increases in internal rotation (+6.5°, P = 0.01) and total range of motion (+7.9°, P = 0.04), whereas relief pitchers had significant worsening of glenohumeral internal rotation deficit (+5.3°, P = 0.04).
Conclusions:
The characteristics of glenohumeral range of motion in major league pitchers did not differ significantly from the beginning to the end of a season, but significant changes did occur between starting and relief pitchers.
Clinical Relevance:
Adaptations to the daily routines of starter and reliever pitchers may be warranted on the basis of these findings.
doi:10.1177/1941738110374627
PMCID: PMC3445183  PMID: 23015997
baseball; pitching; glenohumeral range of motion; shoulder
9.  A Comparative Study on Shoulder Rotational Strength, Range of Motion and Proprioception between the Throwing Athletes and Non-athletic Persons 
Purpose
The repetitive micro traumatic stresses placed on the athletes shoulder joint complex during the throwing motion challenge the surrounding tissues. The purpose of this study was to compare shoulder rotational strength, range of motion and proprioception between the throwing athletes and non-athletic persons.
Methods
Fifteen throwing athletes and 15 non-athletes participated in a nonrandom case – control study. Strength of shoulder rotational movements was tested with a hand held dynamometer. The ranges of internal and external rotation of shoulder were measured by a standard goniometer. The ability of subjects to replicate the target position and kinesthetic sense was examined on the subjects’ right shoulder by using a continuous passive motion device. Independent and paired t tests were used to statistically analyze between and within group differences.
Results
No significant difference was detected on the range of internal rotation between throwing athletes and non-athletic candidates (P=0.3). The range of external rotation was significantly more in athletic subjects (P=0.03). The results also showed that throwing athletes demonstrated a significantly higher isometric strength of shoulder external and internal rotation than the non-athletic group (P<0.05). However, the comparison of the internal and external rotation strength of dominant side in each group showed that throwing athletes showed a significant lower isometric strength of shoulder external rotation than internal rotation (P<0.001). It was also demonstrated higher joint position acuity in the throwing athletes than non athlete subjects (P=0.01).
Conclusion
The repetitive nature of overhead throwing and the high forces that it causes result in adaptive changes of the dominant extremity. Throwing can lead to mobility, strength and neural adaptation.
PMCID: PMC3685158  PMID: 23785574
Throwing Athletes; Muscle Weakness; Mobility Impairment; Proprioception
10.  Relationship Between Maximum Shoulder External Rotation Angle During Throwing and Physical Variables 
The amount of stress imposed on shoulder and elbow appears to be directly correlated with the degree of maximum shoulder external rotation (MER) during throwing motions. Therefore, identifying risk factors contributing to the increase of MER angle may help to decrease the throwing injuries occurrence in baseball players. The purpose of the present study was to demonstrate the correlation between MER and the kinematic variables at stride foot contact (SFC) during the early cocking phase, the passive range of motion (ROM), and the shoulder strength. The subjects were 40 high school baseball players. Each subject carried out five throwing tasks with his maximum effort. A three-dimensional analysis was performed to obtain the MER, and the shoulder angles of external rotation (ER), extension and abduction at SFC in the early cocking phase. The ROM and muscle strength of the shoulder ER and internal rotation (IR) were also measured. Significant moderate linear correlations were found between the MER and the ER (r = -0.32, p = 0.04) at SFC, extension angle ( r= 0.35, p = 0.03) at SFC, IR strength (r = -0.30, p = 0.04) and passive ROM of ER (r = 0.46, p = 0.01). The shoulder IR and extension angles at SFC may determine the degree of the MER angle. Furthermore, weak IR muscle strength and excessive ROM of ER might be risk factors for shoulder and elbow injuries. The finding will enable us to establish better prevention and rehabilitation strategies for throwing injuries in baseball players.
Key pointsIt has been reported that the amount of stress imposed on shoulder and elbow joints is correlated with the degree of maximum shoulder external rotation angle (MER) during throwing. Therefore, controlling MER within a normal range plays a key role in the prevention for throwing-related injuries in baseball players.Physical and biomechanical factors related to the degree of MER must be addressed to advance the current prevention and rehabilitation strategies for the shoulder and elbow injuries.The current finding demonstrated that there was a significant moderate leaner correlation between shoulder internal rotation angle at the initial foot contact in the early cocking phase and MER.
PMCID: PMC3763351  PMID: 24150133
Throwing; shoulder; elbow; injury prevention
11.  THE ACUTE EFFECTS OF TWO PASSIVE STRETCH MANEUVERS ON PECTORALIS MINOR LENGTH AND SCAPULAR KINEMATICS AMONG COLLEGIATE SWIMMERS 
Purpose/Background:
To compare the acute effects of two passive stretches on pectoralis minor length and scapular kinematics among a group of collegiate swimmers.
Methods:
The study was a descriptive design with repeated measures. All procedures were conducted in a biomechanics laboratory and collegiate swimming facility. Fifty asymptomatic shoulders from 29 NCAA swimmers were used (15 control shoulders, 17 focused stretch shoulders, 18 gross stretch shoulders). Pre‐ and post‐test linear pectoralis minor length, as well as scapular kinematics (upward/downward rotation, external/internal rotation, anterior/posterior tilt) were measured as dependent variables. Pectoralis minor length was measured using a standard tape measure and three‐dimensional scapular kinematics were measured using an electromagnetic capture system.
Results:
The gross stretch shoulders had a significant increase in pectoralis minor length compared to the control shoulders (P=.007). There were no other significant changes in length for either the focused stretch or control shoulders (P>.07). No statistically significant (P>.08) differences for all three scapular kinematic variables were found among any of the three groups (P>.08).
Conclusions:
Our results revealed no acute improvements of scapular upward rotation, external rotation, or posterior tilt after the application of either passive stretch maneuver to the pectoralis minor muscle.
Level of Evidence:
2b
PMCID: PMC3578431  PMID: 23439770
Scapular dyskinesis; overhead athlete; muscle; tightness
12.  The Acute Effects of Sleeper Stretches on Shoulder Range of Motion 
Journal of Athletic Training  2008;43(4):359-363.
Context:
The deceleration phase of the throwing motion creates large distraction forces at the shoulder, which may result in posterior shoulder tightness and ensuing alterations in shoulder range of motion (ROM) and may result in an increased risk of shoulder injury. Researchers have hypothesized that various stretching options increase this motion, but few data on the effectiveness of treating such tightness are available.
Objective:
To evaluate the acute effects of “sleeper stretches” on shoulder ROM.
Design:
Descriptive with repeated measures.
Setting:
Biomechanics laboratory and 2 separate collegiate athletic training facilities.
Patients or Other Participants:
Thirty-three National Collegiate Athletic Association Division I baseball players (15 pitchers, 18 position players; age  =  19.8 ± 1.3 years, height  =  184.7 ± 6.4 cm, mass  =  84.8 ± 7.7 kg) and 33 physically active male college students (age  =  20.1 ± 0.6 years, height  =  179.6 ± 6.6 cm, mass  =  83.4 ± 11.3 kg) who reported no recent participation (within 5 years) in overhead athletic activities.
Intervention(s):
Range-of-motion measurements of the dominant shoulder were assessed before and after completion of 3 sets of 30-second passive sleeper stretches among the baseball players. The ROM measurements in the nonthrower group were taken using identical methods as those in the baseball group, but this group did not perform any stretch or movement between measurements.
Main Outcome Measure(s):
Internal and external glenohumeral rotation ROM and posterior shoulder motion (glenohumeral horizontal adduction).
Results:
In the baseball group, posterior shoulder tightness, internal rotation ROM, and external rotation ROM were −3.5° ± 7.7°, 43.8° ± 9.5°, and 118.6° ± 10.9°, respectively, before the stretches and were −1.2° ± 8.8°, 46.9° ± 9.8°, and 119.2° ± 11.0°, respectively, after the stretches. These data revealed increases in posterior shoulder motion (P  =  .01, effect size  =  0.30) and in internal shoulder rotation (P  =  .003, effect size  =  0.32) after application of the stretches. No other differences were observed in the baseball group, and no differences were noted in the nonthrower group.
Conclusions:
Based on our results, the sleeper stretches produced a statistically significant acute increase in posterior shoulder flexibility. However, this change in motion may not be clinically significant.
PMCID: PMC2474815  PMID: 18668168
flexibility; soft tissue; throwing athletes
13.  Internal Rotation Deficits Affect Scapular Positioning in Baseball Players 
Background
Anecdotal evidence suggests an association between glenohumeral internal rotation deficits (GIRD) and scapular dysfunction, an observable alteration in the normal position or motion of the scapula in relation to the thoracic cage.
Questions/purposes
We therefore hypothesized players with GIRD (15° or greater) will have decreased dominant arm scapular upward rotation and increased scapular protraction compared with baseball players with GIRD (14° or less).
Methods
We studied 43 baseball players with no current shoulder or elbow symptoms; 22 had GIRD 15° or greater and 21 had GIRD 14° or less. We measured glenohumeral internal rotation supine with the scapula stabilized. Scapular upward rotation was tested at rest; 60°, 90°, and 120° abduction in the scapular plane; and scapular protraction at 0°, hands on hips, and 90° abduction in the scapular plane.
Results
The GIRD (15° or greater) group had less scapular upward rotation at 60° (3.58), 90° (5.01), and 120° (2.63) in the dominant arm. Scapular protraction at 90° (0.88 cm) also was greater in the dominant arm of the GIRD (15° or greater) group.
Conclusions
Baseball players with more GIRD have alterations to the position and motion of their scapula. A dual goal of minimizing GIRD and strengthening the scapular stabilizers may be warranted in this population.
Level of Evidence
Level II, prognostic study. See Guidelines for Authors for a complete description of levels of evidence.
doi:10.1007/s11999-009-1124-z
PMCID: PMC2865599  PMID: 19841995
14.  GLENOHUMERAL ROTATIONAL RANGE OF MOTION DIFFERENCES BETWEEN FAST BOWLERS AND SPIN BOWLERS IN ELITE CRICKETERS 
Background:
The shoulder, particularly the glenohumeral joint with its predominant reliance upon soft tissues for stability is prone to injury among the cricketers who bowl regularly. These shoulder injuries are more common in spin bowlers than fast bowlers. A decreased internal rotational difference and increased external rotational difference exist when comparing the dominant shoulder with non‐dominant shoulder between overarm cricketers and non‐throwing wicket keepers.
Purpose:
To compare the glenohumeral internal and external rotation range of motion differences between fast bowlers and spin bowlers.
Methods:
A cross‐sectional design was utilized for this study. Thirty‐five fast bowlers and 31 spin bowlers from an elite group were recruited based on the selection criteria. Glenohumeral passive internal and external rotational differences between dominant and non‐dominant shoulders were measured using a standardized mechanical inclinometer.
Results:
Independent t‐tests revealed a statistically significant difference for external rotational difference (p=0.005) between fast and spin bowlers and no such difference for internal rotational difference (p=0.549) between them at 0.05 level.
Conclusion:
External rotational difference is significantly different between fast bowlers and spin bowlers but not internal rotational difference.
Level of Evidence:
Level 4
PMCID: PMC3537464  PMID: 23316421
External rotational difference; glenohumeral internal rotational deficit; glenohumeral joint; internal rotational difference.
15.  Posterior glenohumeral joint capsule contracture 
Shoulder & elbow  2012;4(4):10.1111/j.1758-5740.2012.00180.x.
Glenohumeral joint posterior capsule contracture may cause shoulder pain by altering normal joint mechanics. Contracture is commonly noted in throwing athletes but can also be present in nonthrowers. The cause of contracture in throwing athletes is assumed to be a response to the high amount of repetitive tensile force placed on the tissue, whereas the mechanism of contracture in nonthrowers is unknown. It is likely that mechanical and cellular processes interact to increase the stiffness and decrease the compliance of the capsule, although the exact processes that cause a contracture have not been confirmed. Cadaver models have been used to study the effect of posterior capsule contracture on joint mechanics and demonstrate alterations in range of motion and in humeral head kinematics. Imaging has been used to assess posterior capsule contracture, although standard techniques and quantification methods are lacking. Clinically, contracture manifests as a reduction in glenohumeral internal rotation and/or cross body adduction range of motion. Stretching and manual techniques are used to improve range of motion and often decrease symptoms in painful shoulders.
doi:10.1111/j.1758-5740.2012.00180.x
PMCID: PMC3833448  PMID: 24265649
Shoulder; joint capsule; contracture; athlete; injury; repetitive strain
16.  Internal Rotation and Scapular Position Differences: A Comparison of Collegiate and High School Baseball Players 
Journal of Athletic Training  2010;45(1):44-50.
Abstract
Context:
Conditions such as labral and rotator cuff injuries have been linked with decreases in glenohumeral internal-rotation and increases in external-rotation motion. Also, decreased glenohumeral internal rotation is strongly associated with scapular dyskinesis.
Objective:
To compare healthy collegiate and high school baseball players' glenohumeral joint range of motion and scapular position.
Design:
Cross-sectional study.
Setting:
Institutional research laboratory.
Patients or Other Participants:
Thirty-one male National Collegiate Athletic Association Division I collegiate (age  =  20.23 ± 1.17 years, height  =  186.24 ± 5.73 cm, mass  =  92.01 ± 7.68 kg) and 21 male high school baseball players (age  =  16.57 ± 0.76 years, height  =  180.58 ± 6.01 cm, mass  =  79.09 ± 11.51 kg).
Main Outcome Measure(s):
Glenohumeral internal and external rotation and scapular upward rotation were measured with a digital inclinometer. Scapular protraction was measured with a vernier caliper. All variables except scapular upward rotation were calculated as the difference between the dominant and nondominant sides.
Results:
Collegiate baseball players had more glenohumeral internal-rotation deficit (4.80°, P  =  .028) and total motion deficit (5.73°, P  =  .009) and less glenohumeral external-rotation gain (3.00°, P  =  .028) than high school players. Collegiate baseball players had less scapular upward rotation than high school players at the 90° (4.12°, P  =  .015, versus 3.00°, P  =  .025) and 120° (4.00°, P  =  .007, versus 3.40°, P  =  .005) positions. The scapular protraction difference was greater in collegiate baseball players than in high school players in the hands-on-hips and 90° positions (0.77 cm, P  =  .021, and 1.4 cm, P  =  .001).
Conclusions:
When comparing high school with collegiate baseball players, these data suggest that glenohumeral internal-rotation deficit and scapular position change as the level of competition increases.
doi:10.4085/1062-6050-45.1.44
PMCID: PMC2808753  PMID: 20064047
glenohumeral joint; glenohumeral internal-rotation deficit; scapular dyskinesis
17.  Shoulder Pain in the Overhead Throwing Athlete 
Sports Health  2009;1(2):108-120.
Treatment of the overhead throwing athlete is among the more challenging aspects of orthopaedic sports medicine. Awareness and understanding of the throwing motion and the supraphysiologic forces to which the structures of the shoulder are subjected are essential to diagnosis and treatment. Pain and dysfunction in the throwing shoulder may be attributed to numerous etiologies, including scapular dysfunction, intrinsic glenohumeral pathology (capsulolabral structures), extrinsic musculature (rotator cuff), or neurovascular structures. Attention to throwing mechanics and appropriate stretching, strength, and conditioning programs may reduce the risk of injury in this highly demanding activity. Early discovery of symptoms, followed by conservative management with rest and rehabilitation with special attention to retraining mechanics may mitigate the need for surgical intervention. Prevention of injury is always more beneficial to the long-term health of the thrower than is surgical repair. An anatomic approach is used in this report, focusing on common etiologies of pain in the overhead thrower and emphasizing the clinical presentation and treatment.
doi:10.1177/1941738108331199
PMCID: PMC3445067  PMID: 23015861
shoulder pain; overhead throwing; throwing athlete
18.  Glenoid Stress Distribution in Baseball Players Using Computed Tomography Osteoabsorptiometry: A Pilot Study 
Background
It is important to understand the loading conditions when considering the pathology of shoulder disorders in overhead athletes. However, because throwing is a complicated motion and methods to directly determine stress distribution are complex, direct measurement of the stress distribution across the glenohumeral joint has not been attempted. Subchondral bone density reportedly reflects the cumulative stress acting on a joint surface under actual loading conditions.
Questions/purposes
To assess alterations in stress distribution across the glenoid cavity caused by pitching, we investigated the distribution of subchondral bone density in nonathletic volunteers and asymptomatic baseball players, including fielders and pitchers.
Methods
We collected CT imaging data from the dominant-side shoulder of 10 nonathletic volunteers (controls), 10 fielders, and 10 pitchers in a competitive college baseball league (all men aged 19–24 years, mean 20.7 years). We measured the distribution of subchondral bone density of the glenoid cavity using CT osteoabsorptiometry. The obtained stress distribution map was divided into four segments: anterosuperior, anteroinferior, posteroinferior, and posterosuperior regions. We quantitatively analyzed the location and percentages of high-density regions on the articular surface.
Results
The percentages of high-density regions, including the anteroinferior and posterior segments, were greater in pitchers and fielders than in controls. The percentages of high-density regions did not differ between pitchers and fielders.
Conclusions
The bicentric density patterns indicated that the cumulative force of pitching activity affected the long-term stress distribution across the glenoid cavity.
Clinical Relevance
Our data should be useful for analyzing pitching activity and clarifying the pathology of shoulder disorders associated with throwing.
doi:10.1007/s11999-012-2256-0
PMCID: PMC3348294  PMID: 22290131
19.  An Acute Throwing Episode Decreases Shoulder Internal Rotation 
Background
Glenohumeral internal rotation (GIR) and total arc of motion (TAM) decrease, whereas external rotation (GER) may increase in throwing. Although decreased GIR has been documented after throwing, its time course for recovery and the effect of pitching role have not.
Questions/purposes
We therefore asked (1) how much rotational change occurs after a single throwing episode; (2) do these changes return to baseline by the next throwing episode; and (3) does pitching role affect the amount of change that occurs?
Methods
Forty-five pitchers, starters and relievers, were examined. GIR and GER measurements were taken at five time points (TP): before throwing (TP1); immediately after throwing (TP2); and 24 (TP3), 48 (TP4), and 72 (TP5) hours later. TAM was calculated as the combination of GIR and GER.
Results
GIR decreased from TP1 to TP5 and did not return to baseline. GER changed very little and TAM decreased at TP5. Relievers had greater GIR, GER, and TAM across all time points, but the amount of change over all time points was not different between groups.
Conclusions
GIR was most affected over one 4-day throwing cycle after an acute throwing episode and was less than baseline 72 hours later. Pitching role did not affect the short-term changes.
Clinical Relevance
GIR changes should be expected after an acute throwing episode and conditioning and recovery programs should be used to modify the changes. Because GIR is dynamic, studies on GIR should specifically state when during the pitching cycle the measurement was obtained.
doi:10.1007/s11999-011-2217-z
PMCID: PMC3348325  PMID: 22179981
20.  A Profile of Glenohumeral Internal and External Rotation Motion in the Uninjured High School Baseball Pitcher, Part I: Motion 
Journal of Athletic Training  2011;46(3):282-288.
Context:
The magnitude of motion that is normal for the throwing shoulder in uninjured baseball pitchers has not been established. Chronologic factors contributing to adaptations in motion present in the thrower's shoulder also have not been established.
Objectives:
To develop a normative profile of glenohumeral rotation motion in uninjured high school baseball pitchers and to evaluate the effect of chronologic characteristics on the development of adaptations in shoulder rotation motion.
Design:
Cohort study.
Setting:
Baseball playing field.
Patients or Other Participants:
A total of 210 uninjured male high school baseball pitchers (age = 16±1.1 years, height = 1.8 + 0.1 m, mass = 77.5±11.2 kg, pitching experience = 6±2.3 years).
Intervention(s):
Using standard goniometric techniques, we measured passive rotational glenohumeral range of motion bilaterally with participants in the supine position.
Main Outcome Measure(s):
Paired t tests were performed to identify differences in motion between limbs for the group. Analysis of variance and post hoc Tukey tests were conducted to identify differences in motion by age. Linear regressions were performed to determine the influence of chronologic factors on limb motion.
Results:
Rotation motion characteristics for the population were established. We found no difference between sides for external rotation (ER) at 0° of abduction (t209 = 0.658, P = .51), but we found side-to-side differences in ER (t209 = −13.012, P<.001) and internal rotation (t209 = 15.304, P<.001) at 90° of abduction. Age at the time of testing was a significant negative predictor of ER motion for the dominant shoulder (R2 = 0.019, P = .049) because less ER motion occurred at the dominant shoulder with advancing age. We found no differences in rotation motion in the dominant shoulder across ages (F4,205 range, 0.451–1.730, P>.05).
Conclusions:
This range-of-motion profile might be used to assist with the interpretation of normal and atypical shoulder rotation motion in this population. Chronologic characteristics of athletes had no influence on range-of-motion adaptations in the thrower's shoulder.
PMCID: PMC3419557  PMID: 21669098
shoulder; throwing; range of motion
21.  Glenohumeral Joint Laxity and Stiffness in the Functional Throwing Position of High School Baseball Pitchers 
Journal of Athletic Training  2006;41(1):52-59.
Context: Repetitive overhead throwing has been theorized to result in chronic adaptations to the capsuloligamentous restraints of the glenohumeral joint.
Objective: To compare glenohumeral joint laxity and stiffness between the throwing and nonthrowing shoulders of high school baseball pitchers.
Design: Repeated measures.
Setting: High school athletic training facilities.
Patients or Other Participants: Twenty-two asymptomatic high school baseball pitchers (age = 16.50 ± 0.74 years, height = 178.51 ± 7.66 cm, mass = 75.43 ± 13.24 kg) from a sample of convenience.
Main Outcomes Measure(s): We used computerized stress arthrometry to measure glenohumeral joint laxity and stiffness. Anterior glenohumeral joint laxity and stiffness measures were obtained with the shoulder in 90° of abduction and both neutral rotation and 90° of external rotation. Posterior laxity and stiffness measures were obtained with the shoulder in 90° of abduction and neutral rotation.
Results: No clinically significant differences were found for glenohumeral laxity or stiffness between sides. However, a statistically significant main effect for position was present for both laxity and stiffness. Anterior glenohumeral joint laxity in the 90° external rotation position was significantly decreased and stiffness was increased in this position compared with the anterior at neutral and posterior at neutral positions.
Conclusions: Glenohumeral joint laxity decreases and stiffness increases in the functional throwing position of 90° of abduction and 90° of external rotation. No clinically significant side-to-side differences or directional differences were found in high school baseball pitchers.
PMCID: PMC1421492  PMID: 16619095
shoulder; translation; force displacement; throwing athletes; microinstability; peel-back mechanism
22.  Glenohumeral Range of Motion and Lower Extremity Flexibility in Collegiate-Level Baseball Players 
Sports Health  2012;4(1):25-30.
Background:
The throwing motion results in unilateral increases in dominant arm external rotation (ER) range of motion (ROM). Trunk forward tilt at ball release is related to ball velocity. The relationship between lower quarter flexibility and dominant arm ROM is not known.
Hypothesis:
There is a relationship between lower extremity flexibility and dominant arm ER ROM and total rotation ROM.
Study Design:
Prospective cohort study.
Methods:
Forty-two collegiate baseball pitchers were studied. Demographics, dominant arm, and bilateral glenohumeral ER and internal rotation (IR) ROM were measured. Lower quarter flexibility was assessed via sit-and-reach test. Total rotation motion (TRM) was calculated as ER + IR = TRM. Paired t tests examined differences between the dominant and nondominant arms for ER, IR, and TRM; Pearson product-moment correlation coefficients, shoulder ROM and lower extremity flexibility variables (α = 0.05).
Results:
ER mean value was significantly greater, and IR mean value significantly less, in the dominant arm. TRM mean values were not significantly different bilaterally. Sit-and-reach results were strongly correlated with TRM and ER of the dominant arm.
Conclusions:
There was a significant shift in TRM toward ER in collegiate baseball players. Lower quarter flexibility was strongly correlated with dominant arm ER and total rotation ROM but not in the nondominant arm.
Clinical Relevance:
The sit-and-reach test may be useful to identify a pitcher’s potential to achieve an appropriate amount of trunk forward tilt. This may maximize the lag effect necessary to achieve maximum ER of the dominant arm and increased ball velocity.
doi:10.1177/1941738111422336
PMCID: PMC3435891  PMID: 23016065
pitching; throwing shoulder; range of motion; flexibility
23.  Prevention of Overuse Injuries in Young Baseball Pitchers 
Sports Health  2009;1(6):514-517.
With millions of athletes participating in baseball in the United States annually, overuse injuries are common occurrences. Epidemiological studies, including surveys of orthopaedic surgeons, coaches, and athletes, indicate that injuries such as those to the ulnar collateral ligament are increasing in incidence. Many risk factors for throwing injuries have been proposed—including the immature skeleton, throwing mechanics, glenohumeral internal rotation deficit, pitch type, velocity, and counts—but little evidence is available to support the majority of these factors. Recent studies have shown that pitch volume and overuse are central factors that lead to shoulder and elbow injuries in the young throwing athlete. Pitching while fatigued and in spite of arm pain has also been implicated.
doi:10.1177/1941738109343543
PMCID: PMC3445152  PMID: 23015915
youth pitchers’ injuries; overuse; apophysitis; pitch counts
24.  Effectiveness of Glenohumeral-Joint Stability Braces in Limiting Active and Passive Shoulder Range of Motion in Collegiate Football Players 
Journal of Athletic Training  2004;39(2):151-155.
Objective:
To determine the effectiveness of glenohumeral-joint stability braces in limiting active and passive shoulder abduction and external rotation in collegiate football players.
Design and Setting:
A 2-factor, repeated-measures design was used. The independent variables were brace condition (Denison and Duke Wyre harness, Sawa shoulder brace) and force application (active, passive). The dependent variables were shoulder abduction (45° braced limit) and external-rotation angular displacements.
Subjects:
Fifteen National Collegiate Athletic Association Division I male college football players (age = 19.9 ± 1.37 years, height = 183.2 ± 7.85 cm, mass = 89.9 ± 14.79 kg) participated in the study.
Measurements:
We used the PEAK Motus motion analysis system to measure angular displacements.
Results:
Neither brace maintained the arm position at the 45° braced limit during active or passive shoulder abduction (motion ranged from 56.8° to 73.0°). Although we did not use a priori external-rotation limits in this study, motion ranged from 71.6° to 93.9° with the braces. A repeated-measures multivariate analysis of variance indicated no significant interaction effect (P = .41), but main effects were significant for brace condition and force application (P < .001). Reported differences are statistically significant. For abduction, the Denison and Duke Wyre harness resulted in 12.3° (21%) greater angular displacement than the Sawa shoulder brace, and passive abduction resulted in 3.9° (6%) more angular displacement than active abduction. For external rotation, the Denison and Duke Wyre harness resulted in 6.7° (9%) more angular displacement than the Sawa shoulder brace, and passive external rotation resulted in 15.6° (21%) more angular displacement than active external rotation.
Conclusions:
Preset, braced abduction motion limits were not realized during active and passive physiologic loading of the glenohumeral joint. However, protection against the vulnerable position of 90° of abduction and external rotation was attained at a preset braced limit of 45° of abduction (the exception was the Denison and Duke Wyre harness during passive external rotation). The Sawa shoulder brace was most effective for this purpose.
PMCID: PMC419509  PMID: 15173866
bracing; shoulder joint; angular displacement
25.  The Role of Shoulder Maximum External Rotation During Throwing for Elbow Injury Prevention in Baseball Players 
The objective of the present study was to examine whether the passive range of shoulder external rotation (ER), the maximum shoulder external rotation angle (MER) during throwing, and the ratio of MER to ER are related to the incidence of the elbow injury. A mixed design with one between-factor (a history of the elbow injury) and two within-factors (ER and MER) was used to analyze the difference between baseball players with and without a history of medial elbow pain. Twenty high school baseball players who had experienced the medial elbow pain within the previous month but who were not experiencing the pain on the day of the experiment were recruited (elbow-injured group). Another twenty baseball players who had never experienced the medial elbow pain were also used for testing (control group). MER during throwing, ER, and the ratio of MER to ER were obtained in both of the group. A Mann-Whitney test was used for the group comparison (p < 0.05). The ratio of MER to ER was significantly greater in the elbow-injured group (1.52 ± 0.19) than that in the control group (1.33 ± 0.23) (p = 0.008). On the other hand, there was no statistical significance in MER and ER between two groups. The findings of the study indicate that MER/ER relation could be associated with the incidence of the elbow injury in baseball players.
Key pointsIt is accepted that the greatest elbow valgus stress appears at the position of shoulder maximum external rotation (MER) in the acceleration phase of the throwing movement. As a consequence, shoulders with restricted range of motion of external rotation (ER) compensate with a valgus stress on their elbow joints.In this study, we evaluated the relation between MER and ER of shoulder in players with/without elbow injuries.The result of this study demonstrated that the elbow injured group showed significantly greater MER/ER relation than the control group.The current finding suggests that great MER combined with the ROM restriction may be one of the risk factors to cause medial elbow pain in baseball players.
PMCID: PMC3761461  PMID: 24149453
Throwing; shoulder; maximum external rotation; elbow valgus stress; prevention.

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