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1.  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
2.  Clinical Measures of Shoulder Mobility in the Professional Baseball Player 
Journal of Athletic Training  2005;40(1):23-29.
Context: Professional baseball players must achieve a delicate balance between shoulder mobility and stability to attain optimal sports performance. The sport-specific demands of repetitive overhead throwing may result in an altered mobility-stability relationship.
Objective: To evaluate clinical measures of shoulder mobility in professional baseball players in order to examine differences between the throwing and the nonthrowing shoulders and to describe chronic adaptations to throwing.
Design: Descriptive.
Setting: The athletic training room at Maryvale Baseball Park, Phoenix, AZ.
Patients or Other Participants: Twenty-seven professional baseball players (20 pitchers, 7 position players; age = 20 ± 1.6 years, height = 190.5 ± 4.8 cm, mass = 91.6 ± 9.6 kg) with no previous history of shoulder or elbow injury.
Main Outcome Measure(s): We recorded scapular upward rotation at 4 levels of humeral elevation in the scapular plane (rest, 60°, 90°, 120°); posterior shoulder tightness; and passive, isolated glenohumeral joint internal and external range of motion.
Results: Scapular upward rotation was significantly greater in the throwing shoulder (14.2 ± 6.5°) than in the nonthrowing shoulder (10.6 ± 6.1°) at 90° of humeral elevation (P = .04). We observed no statistically significant difference in posterior shoulder tightness between the throwing (30.2 ± 4.6 cm) and the nonthrowing (28.0 ± 4.8 cm) shoulder (P = .09). In addition, the throwing shoulder exhibited a statistically significant decrease in isolated glenohumeral internal rotation (56.6 ± 12.5°) compared with the nonthrowing shoulder (68.6 ± 12.6°) (P = .001), with a concomitant increase in isolated glenohumeral external rotation (throwing = 108.9 ± 9.0°, nonthrowing = 101.9 ± 5.9°, P = .0014). An analysis of the total arc of motion (internal rotation + external rotation) revealed no statistically significant difference between sides (P = .15).
Conclusions: The throwing shoulder exhibited significant differences in scapular and glenohumeral mobility compared with the nonthrowing shoulder. Further research is necessary to determine the relation of these adaptive changes, if any, to shoulder injury and disability.
PMCID: PMC1088341  PMID: 15902320
glenohumeral joint; scapular upward rotation; posterior shoulder tightness; range of motion
3.  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
4.  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
5.  THORACOLUMBAR RANGE OF MOTION IN BASEBALL PITCHERS AND POSITION PLAYERS 
Introduction/Background:
Optimal baseball throwing mechanics require a significant contribution of thoracolumbar motion, particularly in the sagittal and transverse planes. This motion is key for proper transmission of forces from the lower to upper extremity, thereby minimizing a throwing athlete's risk of injury and maximizing athletic performance.
Purpose:
To define the active‐assisted thoracolumbar ROM of both baseball pitchers and position players and to compare these motions both within and between groups.
Methods:
Fifty‐six asymptomatic, collegiate and minor league baseball pitchers and 42 position players volunteered to participate. Active‐assisted thoracolumbar flexion, extension, and bilateral rotation ROM, were measured in a standing position, using two bubble inclinometers. Two‐tailed t tests were used to determine differences in ROM between and within the pitchers and position players.
Results:
The pitchers had significantly more rotation to the non‐throwing arm side as compared to the position players (p = .007, effect size = .61). The pitchers also had more rotation to the non‐throwing arm side as compared to their throwing side (p = .006, effect size = .47). There were no other significant differences between the pitchers and the position players (p > .53). Furthermore, the position players did not have a side‐to‐side rotation difference (p = .99).
Conclusions:
Pitchers have a greater amount of rotation ROM towards the non‐throwing arm side as compared to position players. Pitchers also have a greater amount of rotation ROM to the non‐throwing arm side as compared to their throwing side rotation. Because pitchers often present with posterior shoulder tightness and subsequent altered shoulder horizontal adduction and internal rotation ROM, the increase in non‐throwing side rotation ROM may occur in response to these adaptations. More specifically, this increase in non‐throwing side trunk rotation ROM may allow such athletes to bring the arm across the body during the follow‐through phase of the throwing motion despite posterior shoulder tightness. However, future research is necessary to investigate this relationship. Based on these results, clinicians should consider these thoracolumbar ROM adaptations in the prevention, evaluation, and treatment of baseball players.
Level of Evidence:
2b
PMCID: PMC3867070  PMID: 24377063
Flexibility; spine; throwing athlete; trunk
6.  Improvements in Shoulder Endurance Following a Baseball-Specific Strengthening Program in High School Baseball Players 
Sports Health  2013;5(3):233-238.
Background:
The posterior shoulder muscles play key roles in maintaining shoulder function in throwing. Arm fatigue has been identified as a risk factor for shoulder and elbow pain in youth baseball pitchers. However, endurance of the posterior shoulder muscles in overhead athletes is not routinely examined or conditioned.
Hypothesis:
Upper extremity muscular endurance can be improved in adolescent baseball players during a 20-week preseason training program. Secondarily, strength will be improved. Finally, these improvements will be associated with maintenance of range of motion.
Study Design:
Cohort study.
Methods:
Fourteen baseball players (age, 16 ± 2 years) attended 3 supervised training sessions per week for 20 weeks. Strengthening of the upper extremity was performed with a specific progression that utilized readily available equipment. Testing was completed at baseline and at 4, 8, and 20 weeks. The posterior shoulder endurance test was performed to assess muscular endurance. Glenohumeral internal and external rotation range of motion and strength were measured.
Results:
Posterior shoulder endurance improved from 30 ± 14 repetitions at baseline to 66 ± 26 at 4 weeks and 88 ± 36 at 20 weeks (P < 0.05). Glenohumeral internal rotation range of motion and the glenohumeral internal/external rotation strength ratio remained similar over the course of the program.
Conclusion:
Implementation of a preseason training program effectively increased shoulder muscular endurance while maintaining strength ratios and range of motion throughout the 20-week program.
Clinical Relevance:
This program improved a key parameter known to be associated with shoulder function and injury risk. This study describes a simple clinical tool to assess muscular endurance of the posterior shoulder.
doi:10.1177/1941738113477604
PMCID: PMC3658410  PMID: 24427394
baseball; adolescent; resistance training
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.  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
9.  Functional Fatigue and Upper Extremity Sensorimotor System Acuity in Baseball Athletes 
Journal of Athletic Training  2007;42(1):90-98.
Context: The sensorimotor system controls the balance between upper extremity stability and mobility during athletic performance. Research indicates that fatigue hampers sensorimotor system function; however, few investigators have studied functional fatigue or multijoint, multiplanar measures.
Objective: To examine the effect of functional fatigue on upper extremity position reproduction in overhead throwing athletes.
Design: Single-session, repeated-measures design.
Setting: University musculoskeletal laboratory.
Patients or Other Participants: Sixteen healthy collegiate baseball players (age = 21.0 ± 1.6 years, height = 175.8 ± 10.2 cm, mass = 82.8 ± 4.3 kg).
Intervention(s): Subjects threw a baseball from a single knee with maximum velocity (every 5 seconds) and rated their level of upper extremity exertion after every 20 throws. Subjects stopped after reporting above level 14 on the Borg scale and began posttests immediately.
Main Outcome Measure(s): We measured active multijoint reproduction of 2 positions: arm cock and ball release. Dependent variables were absolute and variable error for 10 joint motions: scapulothoracic internal-external rotation, upward rotation, and posterior tilt; glenohumeral internal-external rotation, horizontal abduction-adduction, and flexion-extension; elbow pronation-supination and flexion-extension; and wrist ulnar-radial deviation and flexion-extension. We calculated acuity for each joint and the entire upper extremity using 3-dimensional variable error.
Results: Fatigue occurred after an average of 62 ± 28 throws and increased 3-dimensional variable error scores (ie, decreased acuity) of the entire upper extremity and all joints in both positions (P < .05) except for the wrist in arm cock. Fatigue increased errors (ranging from 0.6° to 2.3°) at arm cock for scapulothoracic internal-external rotation, upward rotation, and posterior tilt; glenohumeral internal-external rotation and flexion-extension; elbow flexion-extension; and wrist ulnar-radial deviation and at ball release for scapulothoracic internal-external rotation and upward rotation, glenohumeral horizontal abduction-adduction, elbow pronation-supination, and wrist ulnar-radial deviation and flexion-extension (P < .05).
Conclusions: Functional fatigue affects the acuity of the entire upper extremity, each individual joint, and multiple joint motions in overhead throwers. Clinicians should consider the deleterious effects of upper extremity fatigue when designing injury prevention and rehabilitation programs and should incorporate multijoint and multiplanar endurance exercises. Compromised neuromuscular control of the scapulohumeral relationship may hold pathologic implications for this population as well.
PMCID: PMC1896072  PMID: 17597949
proprioception; multijoint position reproduction; overhead throwing athletes
10.  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
11.  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
12.  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
13.  Glenohumeral Internal Rotation Deficit in the Asymptomatic Professional Pitcher and its Relationship to Humeral Retroversion 
The purpose of this study was to determine if glenohumeral internal rotation deficits (GIRD) exist in an asymptomatic population of professional pitchers, and to assess whether these changes are primarily a bony or soft tissue adaptation. Twenty three, active, asymptomatic professional (Major League Baseball) pitchers volunteered for the study. Clinical measures of glenohumeral ranges of motion, laxity, GIRD, as well as radiographic measures of humeral retroversion were taken by two independent orthopaedic surgeons. Data comparing side to side differences in range of motion, laxity, and humeral retroversion were analyzed for statistical significance using a paired t-test for continuous data and a Chi-squared test for ordinal data, with a significance set at 0.05. Evaluations of statistical correlations between different measurement parameters were accomplished using a Pearson product moment correlation. We hypothesized GIRD will be positively correlated with humeral retroversion (HR) in the pitching arm. All clinical and radiographic measures were made in the field, at spring training, by physicians of both private and institutional based sports medicine practices. For the entire group, significant differences were exhibited for HR, external rotation at 90° and internal rotation at 90°, for dominant vs. non-dominant arms. GIRD of greater than 25° was noted in 10/23 of pitchers. In this group, HR was significantly increased and correlated to GIRD. No such increase or correlation was noted for the non-GIRD group. GIRD is a common finding in asymptomatic professional pitchers, and is related to humeral retroversion. Thus internal rotation deficits should not be used as the sole screening tool to diagnose the disabled throwing shoulder.
Key pointsGIRD is relatively common in asymptomatic baseball pitchers (35-43%).Large ranges (-45 to 5°) and a large standard deviation (±16°) were noted suggesting that GIRD is quite variable in this population.GIRD is a variable measure in the asymptomatic population, and therefore should not be used as sole proof for the disabled throwing shoulder.
PMCID: PMC3763355  PMID: 24150137
Glenohumeral internal rotation; humeral retroversion; pitcher ROM
14.  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
15.  Glenohumeral Rotational Motion and Strength and Baseball Pitching Biomechanics 
Journal of Athletic Training  2012;47(3):247-256.
Context:
Addressing loss of shoulder range of motion and rotator cuff weakness in injury-prevention programs might be an effective strategy for preventing throwing arm injuries in baseball pitchers. However, the influence of these clinical measures on pitching biomechanics is unclear.
Objective:
To evaluate the relationships among clinical measures of shoulder rotational motion and strength and 3-dimensional pitching biomechanics and to evaluate the presence of coupling between the shoulder and the elbow during pitching to provide insight into the influence of clinical shoulder characteristics on elbow biomechanics.
Design:
Cross-sectional study.
Setting:
Biomechanics laboratory.
Patients or Other Participants:
A total of 27 uninjured male high school baseball pitchers (age  =  16 ± 1.1 years, height  =  183 ± 7 cm, mass  =  83 ± 12 kg).
Main Outcome Measure(s):
Clinical measures included shoulder internal- and external-rotation range of motion and peak isometric internal- and external-rotator strength. Three-dimensional upper extremity biomechanics were assessed as participants threw from an indoor pitching mound to a target at regulation distance. Linear regressions were used to assess the influence of clinical measures on the peak shoulder internal and external rotation moments and the peak elbow-adduction moment.
Results:
We found a positive relationship between clinically measured internal-rotator strength and shoulder external-rotation moment (R2  =  0.181, P  =  .04) during pitching. We also noted an inverse relationship between clinically measured external-rotation motion and the elbow-adduction moment (R2  =  0.160, P  =  .04) and shoulder internal-rotation moment (R2  =  0.250, P  =  .008) during pitching. We found a positive relationship between peak shoulder internal-rotation moment and the peak elbow-adduction moment (R2  =  0.815, P < .001) during pitching.
Conclusions:
This study provides insight into the effects of shoulder strength and motion on pitching biomechanics and how these clinical measures might contribute to throwing arm injuries in the baseball pitcher. A relationship also was identified between peak shoulder and elbow moments in the throwing arm during pitching, providing biomechanical support for addressing clinical shoulder characteristics as a potential strategy for preventing elbow injury.
PMCID: PMC3392154  PMID: 22892405
upper extremity; overhead athletes; throwing athletes; rehabilitation
16.  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
17.  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
18.  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
19.  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
20.  Comparison of Shoulder Range of Motion, Strength, and Playing Time in Uninjured High School Baseball Pitchers Who Reside in Warm- and Cold-Weather Climates 
Background
There is an assumption that baseball athletes who reside in warm-weather climates experience larger magnitude adaptations in throwing shoulder motion and strength compared with their peers who reside in cold-weather climates.
Hypotheses
(1) The warm-weather climate (WWC) group would exhibit more pronounced shoulder motion and strength adaptations than the cold-weather climate (CWC) group, and (2) the WWC group would participate in pitching activities for a greater proportion of the year than the CWC group, with the time spent pitching predicting throwing shoulder motion and strength in both groups.
Study Design
Cross-sectional study; Level of evidence, 3.
Methods
One hundred uninjured high school pitchers (50 each WWC, CWC) were recruited. Rotational shoulder motion and isometric strength were measured and participants reported the number of months per year they pitched. To identify differences between groups, t tests were performed; linear regression was used to determine the influence of pitching volume on shoulder motion and strength.
Results
The WWC group pitched more months per year than athletes from the CWC group, with the number of months spent pitching negatively related to internal rotation motion and external rotation strength. The WWC group exhibited greater shoulder range of motion in all planes compared with the CWC group, as well as significantly lower external rotation strength and external/internal rotation strength ratios. There was no difference in internal rotation strength between groups, nor a difference in the magnitude of side-to-side differences for strength or motion measures.
Conclusion
Athletes who reside in cold- and warm-weather climates exhibit differences in throwing shoulder motion and strength, related in part to the number of months spent participating in pitching activities. The amount of time spent participating in pitching activities and the magnitude of range of motion and strength adaptations in athletes who reside in warm-weather climates may make these athletes more susceptible to throwing-related injuries.
doi:10.1177/0363546510382230
PMCID: PMC3923316  PMID: 21051421
glenohumeral joint; rotational motion; rotator cuff; throwing; youth athlete
21.  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
22.  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.
23.  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
24.  Functional Multijoint Position Reproduction Acuity in Overhead-Throwing Athletes 
Journal of Athletic Training  2006;41(2):146-153.
Context: Baseball players rely on the sensorimotor system to uphold the balance between upper extremity stability and mobility while maintaining athletic performance. However, few researchers have studied functional multijoint measures of sensorimotor acuity in overhead-throwing athletes.
Objective: To compare sensorimotor acuity between 2 high-demand functional positions and among planes of motion within individual joints and to describe a novel method of measuring sensorimotor function.
Design: Single-session, repeated-measures design.
Setting: University musculoskeletal research laboratory.
Patients or Other Participants: Twenty-one National Collegiate Athletic Association Division I baseball players (age = 20.8 ± 1.5 years, height = 181.3 ± 5.1 cm, mass = 87.8 ± 9.1 kg) with no history of upper extremity injury or central nervous system disorder.
Main Outcome Measure(s): We measured active multijoint position reproduction acuity in multiple planes using an electromagnetic tracking device. Subjects reproduced 2 positions: arm cock and ball release. We calculated absolute and variable error for individual motions at the scapulothoracic, glenohumeral, elbow, and wrist joints and calculated overall joint acuity with 3-dimensional variable error.
Results: Acuity was significantly better in the arm-cock position compared with ball release at the scapulothoracic and glenohumeral joints. We observed significant differences among planes of motion within the scapulothoracic and glenohumeral joints at ball release. Scapulothoracic internal rotation and glenohumeral horizontal abduction and rotation displayed less acuity than other motions.
Conclusions: We established the reliability of a functional measure of upper extremity sensorimotor system acuity in baseball players. Using this technique, we observed differences in acuity between 2 test positions and among planes of motion within the glenohumeral and scapulothoracic joints. Clinicians may consider these differences when designing and implementing sensorimotor system training. Our error scores are similar in magnitude to those reported using single-joint and single-plane measures. However, 3-dimensional, multijoint measures allow practical, unconstrained test positions and offer additional insight into the upper extremity as a functional unit.
PMCID: PMC1472653  PMID: 16791298
upper extremity; joint position sense; proprioception; throwing athletes
25.  Scapular Contribution for the End-Range of Shoulder Axial Rotation in Overhead Athletes 
The aim of this study was to analyze the relative contribution of the scapular motion on the extreme range-of-motion of shoulder external and internal rotation, in overhead athletes. An electromagnetic tracking device (Flock of Birds) was used to record humeral and scapular kinematics. The dominant arm of 26 male subjects (13 athletes and 13 non-athletes) was studied while subjects actively reached end-range of internal and external rotation. Humeral and scapular angles were calculated and compared across groups by means of a t-test for independent samples. A bivariate correlation approach was used to describe the relationship between humeral angles and scapular variables. The range-of-motion of the thoracohumeral angles, during shoulder external rotation was significantly less (p < 0.05) on the athletes group, athletes also positioned their dominant scapula more retracted and posteriorly tilted. A positive correlation was found between glenohumeral angles and scapular tilt (r = 0.6777; p < 0.05). Concerning internal rotation; athletes showed significantly greater (highest) thoracohumeral angles (p < 0.05). Scapula assumed a position more in retraction and anterior tilt. Based on these findings, it is suggested that differences found in athletes seem to reveal an eventual shoulder adaptation to the throwing mechanics.
Key points
In external rotation end-range, athletes positioned their scapula more in retraction and posterior tilt.
In internal rotation end-range, athletes positioned their scapula more in retraction and anterior tilt.
Results seem to reveal a sport-related shoulder adaptation.
PMCID: PMC3763314  PMID: 24150078
Throwing-shoulder; overhead-athletes; scapular; internal and external rotation

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