Humeral torsion and passive shoulder range in elite volleyball players

Humeral Torsion in Relation to Shoulder Range of Motion in Elite Field Hockey Players

CONTEXT

Sport-specific adaptations in shoulder rotation range of motion (ROM) and the relationship with humeral torsion have been described in overhead-throwing sports. However, information is lacking for other shoulder-loading sports such as field hockey. Therefore, this study's purpose was to evaluate humeral torsion in elite, male field hockey players and explore its association with shoulder ROM.

DESIGN

Cross-sectional study.

METHODS

Twenty-five male, elite field hockey players were included. Humeral torsion and shoulder external and internal rotation ROM were evaluated bilaterally by ultrasound and an inclinometer smartphone application, respectively.

RESULTS

Field hockey players showed a significantly increased humeral retroversion on the dominant compared with the nondominant side (P < .001; Cohen d = 1.75), along with a significantly increased external (P = .004; Cohen d = -0.64) and decreased internal rotation ROM (P = .003; Cohen d = 0.65). This finding illustrates a shift in total shoulder rotational ROM arc. Correlation analysis showed a significant moderate association between the increased humeral retroversion and decreased internal rotation ROM on the dominant side (r = .523).

CONCLUSIONS

Elite male field hockey athletes show sport-specific adaptations regarding humeral torsion and shoulder rotation ROM, similar to throwing athletes. These findings increase our insight into the field hockey athlete's shoulder, which is essential to optimize performance and assist in correctly interpreting shoulder rotational ROM measurements.

Proximal humeral coordinate systems can predict humerothoracic and glenohumeral kinematics of a full bone system

BACKGROUND

Clinical imaging often excludes the distal humerus, confounding definition of common whole-bone coordinate systems. While proximal anatomy coordinate systems exist, no simple method transforms them to whole-bone systems. Their influence on humeral kinematics is unknown.

RESEARCH QUESTION

How do humeral kinematics vary based on proximal and whole-bone coordinate systems, and can average rotation matrices accurately convert kinematics between them?

METHODS

Three proximal coordinate systems were defined by the lesser and greater tuberosities (LT, GT), Crest of the greater tuberosity, and humeral shaft. Average rotation matrices derived from anatomic landmarks on cadaver humeri were generated between the proximal and whole-bone coordinate systems. Absolute angle of rotation was used to determine if anatomical variability within the cadaver population influenced the matrices. The matrices were applied to humerothoracic and glenohumeral motion (collected previously) and analyzed using the proximal coordinate systems, then expressed in the whole-bone system. RMSE was used to compare kinematics from the proximal and whole-bone systems.

RESULTS

A single average rotation matrix between a given proximal and whole-bone coordinate system achieved consistent error, regardless of landmarks. Elevation and plane of elevation had <2° mean error when proximal coordinate systems were transformed to whole-bone kinematics. Axial rotation had a mean 7° error, primarily due to variable humeral head retroversion. Absolute angles of rotation did not statistically differ between subgroups. The average rotation matrices were independent of sex, side, and motion.

SIGNIFICANCE

Proximal humerus coordinate systems can accurately predict whole-bone kinematics, with most error concentrated in axial rotation due to anatomic twist along the bone. These results enhance interpretability and reproducibility in expressing humerothoracic and glenohumeral motion data between laboratories by providing a simple means to convert data between common coordinate systems. This is necessitated by the lack of distal humerus anatomy present in most clinical imaging.

Evaluation of glenohumeral range of motion and humeral retroversion at ages after major change and differences in wrestlers

PURPOSE

This study aimed to present the change in humeral retroversion (HR) angle (HRA) that occurs in childhood and young adulthood and the potential developmental difference that is observed in wrestlers.

METHODS

HRA of dominant and non-dominant shoulders (DSHRA and NDSHRA, respectively) were measured using ultrasonography in a group of 30 wrestlers who started wrestling before the age of 13 years (Group 1), a group of 30 young adults, aged between 16-20 years, who were not actively engaged in any branch of overhead sports (Group 2) and a group of children aged between 11-13 years and not actively engaged in any branch of overhead sports (Group 3). Range of motion (ROM) degrees of dominant and non-dominant shoulders in all groups were compared within each group and between the groups.

RESULTS

DSHRA (mean: 88.73°, 88.93° and 89.40°) values were significantly higher than NDSHRA (mean: 81.13°, 81.83° and 84.37°) values (p < 0.001, p < 0.001 and p < 0,05) in Groups I, II and III, respectively. Internal rotation and total ROM degrees of the dominant shoulder in Group 1 and 3 were higher than those in Group 2.

CONCLUSION

There is no significant change in terms of HRA in people aged between 11-13 and 16-20 years because of natural development or wrestling. DSHRA values are higher than NDSHRA ones. In contrast to the shoulders of throwers, the shoulders of wrestlers are characterized by an increase in internal rotation, described as "Wrestler's shoulder."

LEVEL OF EVIDENCE

Level III.

Junior and Collegiate Tennis Players Display Similar Bilateral Asymmetries of Humeral Retroversion

CONTEXT

Overhead throwing athletes consistently display significant bilateral differences in humeral retroversion (HRV). However, there is limited evidence regarding HRV asymmetries in tennis players despite similarities between the overhead throw and tennis serve.

OBJECTIVE

To determine if junior and collegiate tennis players demonstrate bilateral differences in HRV, and whether the magnitude of the side-to-side difference (HRVΔ) was similar across different age groups.

DESIGN

Cross-Sectional Study Setting: Field-Based Patients or Other Participants: Thirty-nine healthy tennis players were stratified into three age groups: Younger Juniors (n = 11; age = 14.5 ± 0.5 years), Older Juniors (n = 12; age = 17.1 ± 0.9 years), and Collegiate (n = 16; age = 19.6 ± 1.2 years).

MAIN OUTCOME MEASURES

Three-trial means were calculated for HRV for the dominant and nondominant limbs, and HRVΔ was calculated by subtracting the mean of the nondominant side from the dominant side. Paired-sample t-tests were utilized to determine bilateral differences in HRV, while a one-way ANOVA was used to compare HRVΔ between groups.

RESULTS

For all three groups, HRV was significantly greater in the dominant arm compared to the nondominant arm (Younger Juniors: dominant = 62.8° ± 9.1° vs nondominant = 56.3° ± 6.8°, P = .039; Older Juniors: dominant = 75.5° ± 11.2° vs nondominant = 68.6° ± 14.2°, P = .043; Collegiate: dominant = 71.7° ± 8.5° vs nondominant = 61.2° ± 6.9°, P = .001). However, no significant differences were detected in HRVΔ when compared across age groups (P = .511).

CONCLUSIONS

Consistent with studies involving overhead throwing athletes, tennis players demonstrated significantly greater measures of HRV in the dominant limb. Further, the development of HRV asymmetries appear to have occurred prior to the teenage years as no changes were observed in HRVΔ between age groups.

Shoulder Rotation Range of Motion and Serve Speed in Adolescent Male Volleyball Athletes: A Cross-Sectional Study

BACKGROUND

Throwing athletes present alterations in shoulder rotation range of motion (ROM), but not much is known about the relationship between these alterations and performance measurements in volleyball practitioners.

PURPOSE

To compare the passive ranges of motion of internal rotation (IR), external rotation (ER), and total rotation motion (TRM) of the shoulder in dominant and nondominant limbs of young volleyball athletes and to investigate their relationship with ball speed during serves with and without precision (inside and outside court, respectively). The possible association of anthropometrics and competitive practice time with these velocities was also investigated.

STUDY DESIGN

Cross-sectional study.

METHODS

Fifty-seven male volleyball athletes (mean age 17.11 ± 1.88 y; weight 74.68 ± 9.7 kg; height 1.87 ± 0.09 cm) were evaluated for shoulder IR and ER with a bubble goniometer and serve speed inside and outside court was measured with a radar gun. Simple and multiple regression analyses were applied to investigate associations of ROM, anthropometrics, and competitive practice time with serve speed.

RESULTS

Dominant shoulders had diminished IR ROM compared to nondominant shoulders (59.1º ± 16.7º vs 66.4º ± 16.9º; p < 0.001) as well as diminished TRM (173.5º ± 31.8º vs 179.1º ± 29.9º; p < 0.001). Simple regression showed negative association between dominant ER and serve speed outside the court (p = 0.004). Positive associations existed between age and serve speed in both conditions (p < 0.001), BMI and speed inside (p = 0.009) and outside the court (p = 0.008), and between competitive practice time and speed inside (p = 0.008) and outside court (p = 0.003). However, multiple analysis confirmed only age (p < 0.001) and BMI to be associated with ball velocities (inside court p = 0.034; outside court p = 0.031).

CONCLUSION

The results of this study demonstrated that young volleyball athletes presented lower IR and TRM of the shoulder in the dominant upper limb. Age and BMI were directly associated with ball velocities when serving. Passive rotation ROM did not have a relationship with this performance measurement.

LEVEL OF EVIDENCE

3b.

Does humeral torsion play a role in shoulder and elbow injury profiles of overhead athletes: a systematic review

BACKGROUND

Humeral retrotorsion (HRT) is one bony adaptation that occurs in overhead athletes. This bony adaptation often leads to bilateral changes in range of motion at the glenohumeral joint. Because HRT can create different stress environments on the surrounding tissue, it may play a role in upper-limb injury and pain profiles. Therefore, the aim of this review was to examine whether HRT plays a role in shoulder and elbow injury profiles.

METHODS

Two separate critical appraisal tools were administered: the Newcastle-Ottawa Scale (case control) and the Appraisal Tool for Cross-sectional Studies. The primary author extracted all data and obtained means and standard deviations for each outcome. Cohen d effect sizes (ESs) were calculated (ES [95% confidence interval]) for all HRT measurements including nondominant, dominant, and side-to-side differences. Finally, the Strength of Recommendation Taxonomy was used to evaluate the overall strength of the recommendation.

RESULTS

Nine articles were included in this review. Large ESs were present in 2 studies on examination of symptomatic and asymptomatic dominant HRT and ranged between 0.83 (0.08-1.55) and -2.57 (-3.66 to 1.99). The majority of all ESs for all HRT measurements were moderate or low, rendering comparisons between asymptomatic and symptomatic cohorts that were not clinically meaningful.

CONCLUSION

The Strength of Recommendation Taxonomy rating was C based on inconsistent findings. Differences in sports populations and definitions of injuries across studies may be one reason for the varying ESs. HRT does occur in the overhead population, but the degree to which this HRT starts to affect upper-limb injury is unknown and is more than likely player specific and multifactorial.

The Relationship Between Humeral Torsion and Arm Injury in Baseball Players: A Systematic Review and Meta-analysis

CONTEXT

Humeral torsion (HT) has been linked to various injuries and benefits. However, the exact interplay between HT, shoulder range of motion (ROM), competition level differences, and injury risk is unclear.

OBJECTIVE

To determine the relationship between HT, ROM, and injury risk in baseball players. Secondarily, to determine HT based on competition level.

DATA SOURCES

PubMed, Embase, Web of Science, CINAHL, and Cochrane databases were searched from inception until November 4, 2018.

STUDY SELECTION

Inclusion criteria consisted of (1) HT measurements and (2) arm injury or shoulder ROM.

STUDY DESIGN

Systematic review.

LEVEL OF EVIDENCE

Level 3.

DATA EXTRACTION

Two reviewers recorded patient demographics, competition level, HT, shoulder ROM, and injury data.

RESULTS

A total of 32 studies were included. There was no difference between baseball players with shoulder and elbow injuries and noninjured players (side-to-side HT difference: mean difference [MD], 1.75 [95% CI, -1.83 to 2.18]; dominant arm: MD, 0.17 [95% CI, -1.83 to 2.18]). Meta-regression determined that for every 1° increase in shoulder internal rotation (IR), there was a subsequent increase of 0.65° in HT (95% CI, 0.28 to 1.02). HT did not explain external rotation (ER ROM: 0.19 [95% CI, -0.24 to 0.61]) or horizontal adduction (HA ROM: 0.18 [95% CI, -0.46 to 0.82]). There were no differences between HT at the high school, college, or professional levels.

CONCLUSION

No relationship was found between HT and injury risk. However, HT explained 65% of IR ROM but did not explain ER ROM or HA ROM. There were no differences in HT pertaining to competition level. The majority of IR may be nonmodifiable. Treatment to restore and maintain clinical IR may be important, especially in players with naturally greater torsion. HT adaptation may occur prior to high school, which can assist in decisions regarding adolescent baseball participation.

COMPARISON OF GLENOHUMERAL JOINT ROTATION RANGE OF MOTION IN YOUNG ATHLETES

ABSTRACT Introduction: Overhead-throwing athletes undergo changes in shoulder range of motion (ROM) due to sports activities, such as excessive amplitude, lateral rotation (LR) increase and medial rotation (MR) restriction. Asymmetry greater than 20° may render athletes more prone to injuries. There are similarities among sports featuring overhead throwing due to the considerable amount of movements involving maximum lateral rotation. In these sports, medial rotation (MR) restriction, excess of lateral rotation (LR) and shoulder pain are common, particularly in overhead-throwing athletes. Objective: To assess shoulder MR and LR ROM in athletes participating in different sports, considering the influence of these variables on injuries and functional performance. Methods: The rotation ROM of the glenohumeral joint was assessed in 477 young athletes, who were categorized in three sports groups: swimming, overhead-throwing and non-overhead throwing, distributed by age group. Analyses of Variance (ANOVA) were performed to verify if there were differences in MR and LR between groups and paired Student t test was used to verify differences between sides (asymmetry). Results: Youngest athletes showed significant shorter LR than the oldest, in both sides. This study demonstrated that the right side has less MR and greater LR in all groups. Conclusion: The findings showed that overhead-throwing and swimming groups have similarities in shoulder rotation ROM. Level of evidence III; Diagnostic Studies - Investigating a Diagnostic Test.

Spiking Kinematics in Volleyball Players With Shoulder Pain

CONTEXT

Spiking is one of the most frequently used scoring techniques in volleyball games, and around 80% of shoulder pain in volleyball players is linked with the spiking movement.

OBJECTIVE

To investigate the differences in glenohumeral joint, scapular, and trunk movements during the spiking motion between volleyball players with and those without shoulder pain.

DESIGN

Cross-sectional study.

SETTING

University laboratory.

PATIENTS OR OTHER PARTICIPANTS

Twenty amateur volleyball players with shoulder pain (age = 21.8 ± 1.79 years, with an average of 4.0 ± 0.92 years of volleyball experience and 6.0 ± 3.51 months of shoulder pain) and 20 sex-, age-, and experience-matched control participants.

MAIN OUTCOME MEASURE(S)

The 3-dimensional kinematics of the shoulder joint, scapula, and trunk during spiking were assessed using an electromagnetic tracking system.

RESULTS

Compared with the control group, individuals with shoulder pain demonstrated less scapular posterior tilt ( P = .041) and more glenohumeral horizontal abduction ( P = .008) and scapular internal rotation ( P = .02) at ball contact when performing the cross-body spike.

CONCLUSIONS

The decrease in scapular posterior tilt, along with increased glenohumeral horizontal abduction and scapular internal rotation, was associated with shoulder pain in university volleyball players. These changes should be addressed in the training and treatment of young volleyball players.

Glenohumeral Rotational Deficit and Suprascapular Neuropathy in the Hitting Shoulder in Male Collegiate Volleyball Players

Objective

Repetitive overhead movements stress the dominant shoulder of volleyball players, potentially causing glenohumeral internal rotation deficit (GIRD) and suprascapular neuropathy. The aim of this study was to determine the prevalence of pathological GIRD and suprascapular neuropathy in male collegiate volleyball players.

Methods

We evaluated 22 male collegiate volleyball players and compared the range of motion, the isometric shoulder strength, the thickness of the infraspinatus (ISP) muscle, and the latency and amplitude of the suprascapular nerve [in a nerve conduction study (NCS)] between the hitting and contralateral shoulders. Correlations between the physical findings and each parameter were also determined.

Results

The internal rotation angle of the hitting shoulder (55.1±8.7°) was significantly less than that of the contralateral shoulder (64.5±10.2°) (P<0.001); pathological GIRD (≥20°) was found in four players (18.2%). Three players (13.6%) showed abnormal electrophysiological findings of the suprascapular nerve on the ISP muscle in the hitting shoulder. The external-to-internal rotation (ER/IR) torque ratio in the hitting shoulder (99±18%) was significantly lower than that in the contralateral shoulder (106±12%) (P=0.04); no significant differences were observed in ISP muscle thickness or NCS data between the hitting and contralateral shoulders.

Conclusion

The prevalence of pathological GIRD in male collegiate volleyball players was consistent with that of previous studies. Meanwhile, the prevalence of suprascapular neuropathy was less than that previously reported in high-level volleyball players. Preventive posterior rotator cuff strengthening programs are recommended to correct imbalances between ER and IR in the hitting shoulder, thereby decreasing the risk of shoulder injury.

Reliability and Validity of a 1-Person Technique to Measure Humeral Torsion Using Ultrasound

CONTEXT

  Knowledge of the bilateral difference in humeral torsion (HT) enables clinicians to implement appropriate interventions for soft tissue restrictions of the shoulder to restore rotational motion and reduce injury risk. Whereas the current ultrasound method for measuring HT requires 2 assessors, a more efficient 1-person technique (1PT) may be of value.

OBJECTIVE

  To determine if a 1PT is a reliable and valid alternative to the established 2-person technique (2PT) for indirectly measuring HT using ultrasound.

DESIGN

  Descriptive laboratory study.

SETTING

  Biomechanics laboratory.

PATIENTS OR OTHER PARTICIPANTS

  A convenience sample of 16 volunteers (7 men, 9 women; age = 26.9 ± 6.8 years, height = 172.2 ± 10.7 cm, mass = 80.0 ± 13.3 kg).

MAIN OUTCOME MEASURE(S)

  We collected the HT data using both the 1PT and 2PT from a total of 30 upper extremities (16 left, 14 right). Within-session intrarater reliability (intraclass correlation coefficient; ICC [3,1]) and standard error of measurement (SEM) were assessed for both techniques. Simple linear regression and Bland-Altman analysis were used to examine the validity of the 1PT when compared with the established 2PT.

RESULTS

  The 1PT (ICC [3,1] = 0.992, SEM = 0.8°) and 2PT (ICC [3,1] = 0.979, SEM = 1.1°) demonstrated excellent within-session intrarater reliability. A strong linear relationship was demonstrated between the HT measurements collected with both techniques ( r = 0.963, r² = 0.928, F_1,28 = 361.753, P < .001). A bias of -1.2° ± 2.6° was revealed, and the 95% limits of agreement indicated the 2 techniques can be expected to vary from -6.3° to 3.8°.

CONCLUSIONS

  The 1PT for measuring HT using ultrasound was a reliable and valid alternative to the 2PT. By reducing the number of testers involved, the 1PT may provide clinicians with a more efficient and practical means of obtaining these valuable clinical data. ^a.

Shoulder Bone Geometry Affects the Active and Passive Axial Rotational Range of the Glenohumeral Joint

BACKGROUND

The range of motion of the glenohumeral joint varies substantially among individuals and is dependent on humeral position. How variation in shape of the humerus and scapula affects shoulder axial range of motion at various positions has not been established.

PURPOSE

To quantify variation in the shape of the glenohumeral joint and investigate whether the scapula and humerus geometries affect the axial rotational range of the glenohumeral joint.

STUDY DESIGN

Descriptive laboratory study.

METHODS

The range of active and passive internal-external rotation of the glenohumeral joint was quantified for 10 asymptomatic participants with optical motion tracking at 60º, 90º, and 120º humeral elevations in the coronal, scapular, and sagittal planes. Bone geometrical parameters were acquired from shoulder magnetic resonance image scans, and correlations between geometrical parameters and maximum internal and external rotations were investigated. Three-dimensional participant-specific models of the humerus and scapula were used to identify collisions between bones at the end of range.

RESULTS

Maximum internal and external rotations of the glenohumeral joint were correlated to geometric parameters and were limited by bony collisions. Generally, the active axial rotational range was greater with increased articular cartilage and glenoid curvature, while a shorter acromion resulted in greater passive range. Greater internal rotation was correlated with a greater glenoid depth and curvature in the scapular plane ( r = 0.76, P < .01, at 60° of elevation), a greater subacromial depth in the coronal plane ( r = 0.74, P < .01, at 90° of elevation), and a greater articular cartilage curvature in the sagittal plane ( r = 0.75, P < .01, at 90° of elevation). At higher humeral elevations, a greater subacromial depth and shorter acromion allowed a greater range of motion.

CONCLUSION

The study strongly suggests that specific bony constraints restrict the maximum internal and external rotations achieved in active and passive glenohumeral movement.

CLINICAL RELEVANCE

This study identifies bony constraints that limit the range of motion of the glenohumeral joint. This information can be used to predict full range of motion and set patient-specific rehabilitation targets for those recovering from shoulder disorders. It can improve positioning and choice of shoulder implants during preoperative planning by considering points of collision that could limit range of motion.

The Relationship Between Humeral Retrotorsion and Shoulder Range of Motion in Baseball Players With an Ulnar Collateral Ligament Tear

BACKGROUND

Humeral retrotorsion has been investigated in relation to shoulder range of motion (ROM) in healthy baseball players. Currently, there is limited information on the osseous anatomy and development of ulnar collateral ligament (UCL) tears.

PURPOSE

To determine the relationship between humeral retrotorsion and shoulder ROM in baseball players with a UCL tear.

STUDY DESIGN

Cross-sectional study; Level of evidence, 3.

METHODS

Fifty-four baseball players (mean age, 18.5 ± 2.0 years) with a UCL tear volunteered for this study. Participants were measured bilaterally for shoulder internal (IR) and external rotation (ER) ROM and humeral retrotorsion. Differences between sides (involved to uninvolved) were used to calculate the glenohumeral internal rotation deficit (GIRD), external rotation ROM difference (ERDiff), total rotational motion difference (TRM), and humeral retrotorsion difference (HTDiff). A multivariate regression analysis was performed with GIRD, ERDiff, and TRM regressing on HTDiff. Univariate analysis was performed to further evaluate the effect of the predictors on each outcome separately. To control for the effect of age, weight, duration of symptoms, and years of experience, the variables were included as covariates. An a priori level was set at P < .05.

RESULTS

There was a statistically significant relationship between the GIRD, ERDiff, and TRM results compared with HTDiff (P = .003). Independent analysis revealed a statistically significant relationship between GIRD and HTDiff (P = .004) and between ERDiff and HTDiff (P = .003) but no significant relationship between TRM and HTDiff (P = .999). After adjusting for age, weight, duration of symptoms, years of experience, dominant arm, and position, a significant relationship was found between GIRD and HTDiff (P = .05) and between ERDiff and HTDiff (P = .01). No significant relationship was found between TRM and HTDiff (P = .54). Adjusted univariate regression analysis determined that HTDiff explains approximately 16% of the variance in GIRD (r² = 0.158) and approximately 24% of the variance in ERDiff (r² = 0.237).

CONCLUSION

In baseball players with a UCL tear, approximately 16% of the variance in GIRD and 24% of the variance in ERDiff can be attributed to differences found in humeral retrotorsion between sides. This indicates that humeral retroversion contributes significantly to GIRD and increased ER ROM in baseball players. Recognition of differences in humeral retrotorsion between the dominant and nondominant upper extremities may help explain some but not all of the changes in shoulder ROM commonly seen in baseball players.

The volleyball athlete's shoulder: biomechanical adaptations and injury associations

In volleyball, the dominant shoulder of the athlete undergoes biomechanical and morphological adaptations; however, definitive conclusions about their exact nature, aetiology, purpose and associations with shoulder injury have not been reached. We present a systematic review of the existing literature describing biomechanical adaptations in the dominant shoulders of volleyball players and factors that may predispose to shoulder pain/injury. A thorough literature search via Medline, EMBASE and SCOPUS was conducted for original studies of volleyball players and 15 eligible articles were identified. Assessment of study quality was performed using the STROBE statement. The reviewed literature supports the existence of a glenohumeral internal rotation deficit (GIRD) and a possible (and less pronounced) external rotation gain in the dominant vs. the non-dominant shoulder of volleyball athletes. Unlike other overhead sports, the GIRD in volleyball athletes appears to be anatomical as a response to the repetitive overhead movements and not to be associated with shoulder pain/injury. Additionally, the dominant shoulder exhibits muscular imbalance, which appears to be a significant risk factor for shoulder pain. Strengthening of the external rotators should be used alongside shoulder stretching and joint mobilisations, core strengthening and optimisation of spike technique as part of injury management and prevention programmes.

Dominant vs. non-dominant shoulder morphology in volleyball players and associations with shoulder pain and spike speed

The aims of our study were to compare the dominant (DOM) and non-dominant (NDOM) shoulders of high-level volleyball athletes and identify possible associations of shoulder adaptations with spike speed (SS) and shoulder pathology. A total of 22 male volleyball players from two teams participating in the first division of the Cypriot championship underwent clinical shoulder tests and simple measurements around their shoulder girdle joints bilaterally. SS was measured with the use of a sports speed radar. Compared with the NDOM side, the DOM scapula was more lateralised, the DOM dorsal capsule demonstrated greater laxity, the DOM dorsal muscles stretching ability was compromised, and the DOM pectoralis muscle was more lengthened. Players with present or past DOM shoulder pain demonstrated greater laxity in their DOM dorsal capsule, tightening of their DOM inferior capsule, and lower SS compared with those without shoulder pain. Dorsal capsule measurements bilaterally were significant predictors of SS. None of the shoulder measurements was associated with team roles or infraspinatus atrophy, while scapular lateralisation was more pronounced with increasing years of experience, and scapular antetilting was greater with increasing age. Adaptations of the DOM shoulder may be linked to pathology and performance. We describe simple shoulder measurements that may have the potential to predict chronic shoulder injury and become part of injury prevention programmes. Detailed biomechanical and large prospective studies are warranted to assess the validity of our findings and reach more definitive conclusions.

Divergence in male and female manipulative behaviors with the intensification of metallurgy in Central Europe

Humeral morphology has been shown to reflect, in part, habitual manipulative behaviors in humans. Among Central European agricultural populations, long-term social change, increasing task specialization, and technological innovation all had the potential to impact patterns of habitual activity and upper limb asymmetry. However, systematic temporal change in the skeletal morphology of agricultural populations in this region has not been well-characterized. This study investigates diachronic patterns in humeral biomechanical properties and lengths among 174 adult Central European agriculturalists through the first ∼ 5400 years of farming in the region. Greater asymmetry in biomechanical properties was expected to accompany the introduction of metallurgy, particularly in males, while upper limb loading patterns were expected to be more similar between the Bronze and Iron Ages. Results revealed a divergence in the lateralization of upper limb biomechanical properties by sex between the Early/Middle Neolithic and Early/Middle Bronze Age. Neolithic females had significantly more variable properties than males in both humeri, while Bronze Age female properties became homogeneous and very symmetrical relative to the right-biased lateralization of contemporaneous males. The Bronze Age to Iron Age transition was associated with morphological change among females, with a significant increase in right-biased asymmetry and a concomitant reduction in sexual dimorphism. Relative to biomechanical properties, humeral length variation and asymmetry were low though some significant sexual dimorphism and temporal change was found. It was among females that the lateralization of humeral biomechanical properties, and variation within them, changed most profoundly through time. This suggests that the introduction of the ard and plow, metallurgical innovation, task specialization, and socioeconomic change through ∼ 5400 years of agriculture impacted upper limb loading in Central European women to a greater extent than men.

Morphologic features of humeral head and glenoid version in the normal glenohumeral joint

BACKGROUND

The morphologic features and clinical significance of version of the humeral head and glenoid remain unclear. The purpose of this study was to evaluate the normal values of humeral head version and glenoid version on computed tomography scans and to clarify their features in the normal glenohumeral joint.

METHODS

Images for analysis were computed tomography scans of 410 normal shoulders from healthy volunteers. Values of humeral head and glenoid version were measured. In glenoid version measurement, 3-dimensionally corrected slices were reconstructed to eliminate scapular inclination. Differences in humeral head version and glenoid version were assessed between dominant and nondominant shoulders and between men and women. Correlation analyses were also performed in the values of version between dominant and nondominant shoulders and between humeral head version and glenoid version.

RESULTS

The values of humeral head retroversion were widely distributed from -2° to 60°, with an average of 26° ± 11°. Average glenoid retroversion was 1° ± 3°, ranging from -9° to 13°. Both humeral head retroversion and glenoid retroversion were significantly higher on the dominant side than on the nondominant side and significantly higher in men than in women. Humeral head version and glenoid version values were well correlated with those of the contralateral shoulder. No correlation was found between humeral head version and glenoid version.

CONCLUSIONS

This study found differences in humeral head version and glenoid version by sex and shoulder dominance in a large sample. Both the humeral head and glenoid are thought to be more retroverted in high-demand shoulders.

Dominant-limb range-of-motion and humeral-retrotorsion adaptation in collegiate baseball and softball position players

CONTEXT

Biomechanically, the motions used by baseball and softball pitchers differ greatly; however, the throwing motions of position players in both sports are strikingly similar. Although the adaptations to the dominant limb from overhead throwing have been well documented in baseball athletes, these adaptations have not been clearly identified in softball players. This information is important in order to develop and implement injury-prevention programs specific to decreasing the risk of upper extremity injury in softball athletes.

OBJECTIVE

To compare range-of-motion and humeral-retrotorsion characteristics of collegiate baseball and softball position players and of baseball and softball players to sex-matched controls.

DESIGN

Cross-sectional study.

SETTING

Research laboratories and athletic training rooms at the University of North Carolina at Chapel Hill.

PATIENTS OR OTHER PARTICIPANTS

Fifty-three collegiate baseball players, 35 collegiate softball players, 25 male controls (nonoverhead athletes), and 19 female controls (nonoverhead athletes).

INTERVENTION(S)

Range of motion and humeral retrotorsion were measured using a digital inclinometer and diagnostic ultrasound.

MAIN OUTCOME MEASURE(S)

Glenohumeral internal-rotation deficit, external-rotation gain, total glenohumeral range of motion, and humeral retrotorsion.

RESULTS

Baseball players had greater glenohumeral internal-rotation deficit, total-range-of-motion, and humeral-retrotorsion difference than softball players and male controls. There were no differences between glenohumeral internal-rotation deficit, total-range-of-motion, and humeral-retrotorsion difference in softball players and female controls.

CONCLUSIONS

Few differences were evident between softball players and female control participants, although range-of-motion and humeral-retrotorsion adaptations were significantly different than baseball players. The throwing motions are similar between softball and baseball, but the athletes adapt to the demands of the sport differently; thus, stretching/strengthening programs designed for baseball may not be the most effective programs for softball athletes.

Changes in humeral torsion and shoulder rotation range of motion in high school baseball players over a 1-year period

BACKGROUND

The torsional stress on a baseball player's throwing limb has been theorized to affect humeral retrotosion during skeletal maturity. This study investigated 1) changes in humeral retrotorsion and shoulder rotation range of motion over a 1-year period in high school baseball players, and 2) relationship between a 1-year change in dominant limb retrotorsion and the number of seasons participants played on organized baseball teams.

METHODS

Humeral retrotorsion and shoulder range of motion were measured a year apart in a total of 138 high school baseball players. Baseball participation history over the year was captured using a questionnaire. Changes in bilateral humeral retrotorsion and range of motion over a year and effects of baseball participation on changes in humeral retrotorsion and range of motion were assessed using analysis of variance models.

FINDINGS

Humeral retrotorsion did not significantly change over the year regardless of the number of seasons participants played baseball (P>0.05). The participants' dominant limb internal rotation range of motion decreased slightly over a year (2.0°, P=0.015), while external rotation (7.8°, P<0.01) and total rotation (11.9°, P<0.01) range of motion decreased bilaterally among the participants who only played baseball in 1 season.

INTERPRETATION

Adaptation in humeral retrotorsion seems to occur prior to high school age. Our observations suggest that change in shoulder range of motion in high school baseball players are attributed to soft tissue contracture. This provides a support that stretching exercises should be implemented when significant changes in range of motion are identified in high school baseball players.

Upper limb biomechanics during the volleyball serve and spike

Background:

The shoulder is the third-most commonly injured body part in volleyball, with the majority of shoulder problems resulting from chronic overuse.

Hypothesis:

Significant kinetic differences exist among specific types of volleyball serves and spikes.

Study Design:

Controlled laboratory study.

Methods:

Fourteen healthy female collegiate volleyball players performed 5 successful trials of 4 skills: 2 directional spikes, an off-speed roll shot, and the float serve. Volunteers who were competent in jump serves (n, 5) performed 5 trials of that skill. A 240-Hz 3-dimensional automatic digitizing system captured each trial. Multivariate analysis of variance and post hoc paired t tests were used to compare kinetic parameters for the shoulder and elbow across all the skills (except the jump serve). A similar statistical analysis was performed for upper extremity kinematics.

Results:

Forces, torques, and angular velocities at the shoulder and elbow were lowest for the roll shot and second-lowest for the float serve. No differences were detected between the cross-body and straight-ahead spikes. Although there was an insufficient number of participants to statistically analyze the jump serve, the data for it appear similar to those of the cross-body and straight-ahead spikes. Shoulder abduction at the instant of ball contact was approximately 130° for all skills, which is substantially greater than that previously reported for female athletes performing tennis serves or baseball pitches.

Conclusion:

Because shoulder kinetics were greatest during spiking, the volleyball player with symptoms of shoulder overuse may wish to reduce the number of repetitions performed during practice. Limiting the number of jump serves may also reduce the athlete’s risk of overuse-related shoulder dysfunction.

Clinical Relevance:

Volleyball-specific overhead skills, such as the spike and serve, produce considerable upper extremity force and torque, which may contribute to the risk of shoulder injury.

Humeral retrotorsion in collegiate baseball pitchers with throwing-related upper extremity injury history

Background:

Collegiate baseball pitchers, as well as position players, exhibit increased humeral retrotorsion compared with individuals with no history of overhead sport participation. Whether the humeral retrotorsion plays a role in the development of throwing-related injuries that are prevalent in collegiate baseball pitchers is unknown.

Hypotheses:

Humeral retrotorsion will be significantly different in collegiate pitchers with throwing-related shoulder or elbow injury history compared with pitchers with no injury history. Humeral retrotorsion can also discriminate participants with and without shoulder or elbow injury.

Study Design:

Cross-sectional study.

Methods:

Comparisons of ultrasonographically-obtained humeral retrotorsion were made between 40 collegiate pitchers with and without history of throwing-related shoulder or elbow injury. The ability of humeral retrotorsion to discriminate injury history was determined from the receiver operating characteristic area under the curve.

Results:

Participants with an elbow injury history demonstrated a greater humeral retrotorsion limb difference (mean difference = 7.2°, P = 0.027) than participants with no history of upper extremity injury. Participants with shoulder injury history showed no differences in humeral torsion compared with participants with no history of injury. Humeral retrotorsion limb difference exhibited a fair ability (receiver operating characteristic area under the curve = 0.74) to discriminate elbow injury history.

Conclusions:

Collegiate pitchers with a history of elbow injury exhibited a greater limb difference in humeral retrotorsion compared with pitchers with no history of injury. No differences in humeral retrotorsion variables were present in participants with and without shoulder injury history.

Clinical Relevance:

Baseball players with a history of elbow injury demonstrated increased humeral retrotorsion, suggesting that the amount of retrotorsion and the development of elbow injury may be associated.

Passive and dynamic shoulder rotation range in uninjured and previously injured overhead throwing athletes and the effect of shoulder taping

OBJECTIVES

To investigate: (1) the passive and dynamic shoulder internal (IR) and external (ER) rotation range of motion (ROM) of 2 groups of asymptomatic overhead throwing athletes: one group who had never experienced shoulder symptoms and another who had shoulder symptoms >12 months ago, (2) the effect of taping on the passive and dynamic IR-ER ROM in both these groups.

DESIGN

A within-subject repeated measures analysis of variance design to determine the differences in passive and dynamic shoulder rotation range and the effect of shoulder taping on the rotation range in a group of uninjured and previously injured overhead throwing athletes.

SETTING

Academic institution sports medicine setting.

PARTICIPANTS

Twenty-six overhead throwing collegiate athletes: 17 with no history of shoulder injury and 9 with previous shoulder injury.

METHODS

Passive shoulder ROM was measured with a goniometer with the subject in the supine position. To measure dynamic ROM, the subjects sat on a chair and threw a handball into a net. An 8-camera Vicon Motion Capture system recorded markers placed on the upper limb and trunk. Dynamic ROM was calculated with inverse kinematics by using OpenSim.

MAIN OUTCOME MEASUREMENT

Shoulder IR-ER ROM.

RESULTS

Dynamic IR-ER ROM was significantly greater than passive IR-ER ROM (P < .0001). There was no difference in passive IR-ER ROM between the uninjured and previously injured overhead throwing athletes. However, there was a significant difference in the total dynamic IR-ER ROM, whereby the overhead throwing athletes who had never experienced shoulder symptoms had less IR-ER ROM than the previously injured group (173.9° versus 196.9°, respectively; P = .049). Taping the shoulder increased the passive ROM in both groups of subjects (P < .001), increased the dynamic IR-ER ROM in the uninjured subjects, but decreased the dynamic IR-ER ROM in the previously injured subjects, although this was not statistically significant (P = .07).

CONCLUSIONS

Passive IR-ER ROM is a poor indication of dynamic shoulder function. Athletes who have had a previous shoulder injury demonstrate a greater dynamic IR-ER ROM than athletes who have never had a shoulder injury. Shoulder taping decreased the dynamic range of the previously injured athlete, so that it was nearer the dynamic range of the uninjured athlete. Shoulder taping might provide increased protection for the injured athlete by decreasing the dynamic IR-ER ROM and by facilitating better shoulder and scapular muscle control. Further studies are necessary to demonstrate whether this finding is clinically significant.

Bony adaptation of the proximal humerus and glenoid correlate within the throwing shoulder of professional baseball pitchers

BACKGROUND

Elite throwing athletes have increased proximal humeral retrotorsion (HRT) and glenoid retroversion (GRV) in their throwing shoulders compared with their nonthrowing shoulders. These adaptive morphologic changes are thought to be independently protective against shoulder injury; however, their relationship to each other is poorly understood.

PURPOSE

To determine if an association exists between HRT and GRV within the same shoulders of professional pitchers.

STUDY DESIGN

Cross-sectional study; Level of evidence, 3.

METHODS

The HRT and GRV measurements were determined using published techniques in asymptomatic bilateral shoulders of 32 professional pitchers (mean age, 23 years). Three measurements for each variable were averaged, and the reliability of the techniques was verified. The relationship between HRT and GRV within the same shoulders was determined with Pearson correlation coefficients. Paired t tests were used to compare HRT and GRV between the throwing and nonthrowing shoulder. Simple ratios were calculated between HRT and GRV.

RESULTS

Humeral retrotorsion and GRV were both significantly greater on the throwing side compared with the nonthrowing side (HRT: throwing = 9.0° ± 11.4° and nonthrowing = 22.1° ± 10.7°, P < .001; GRV: throwing = 8.6° ± 6.0° and nonthrowing = 4.9° ± 4.8°, P = .001). Within the same shoulders, there was a statistically significant positive association between HRT and GRV on the throwing side (r = 0.43, P = .016) but not on the nonthrowing side (r = -0.13, P = .50). The HRT:GRV ratio was 2.3:1 for throwing shoulders and 7:1 for nonthrowing shoulders.

CONCLUSION

The concurrent increases in dominant shoulder HRT and GRV were observed as a 2:1 "thrower's ratio." As this relationship was not observed on the nondominant shoulder, it suggests that bony adaptation of the proximal humerus and glenoid are coupled during skeletal development in the throwing shoulder. Longitudinal studies are needed to confirm this hypothesis.

Ultrasonographic assessment of humeral retrotorsion in baseball players: a validation study

BACKGROUND

Recently, clinicians and researchers started using diagnostic ultrasound to measure humeral torsion as an alternative to radiological assessments in overhead-throwing athletes and other clinical populations. Ultrasound appears to be a reliable, nonradiological alternative, but ultrasound assessment has not been validated against computed tomography (CT), the current gold standard.

PURPOSE

This study aimed to establish the validity of an ultrasound assessment of humeral torsion by comparing data obtained using both ultrasound and CT, the current standard.

STUDY DESIGN

Cohort study (Diagnosis); Level of evidence, 2.

METHODS

Humeral torsion was measured using both ultrasound and CT in 24 collegiate-aged baseball players. Comparisons between the assessments were made using both regression and Bland-Altman plots. Reliability and precision were also established.

RESULTS

A strong relationship existed between humeral torsion variables obtained with ultrasound and CT (R = .797, R (2) = .635, P < .001). The ultrasound assessment yielded reliability coefficients ranging from .991 to .997, with approximately 1° of measurement error. The CT method's reliability coefficients ranged from .805 to .933, with approximately 3.5° of measurement error.

CONCLUSION

There was a strong relationship between humeral torsion obtained with ultrasound and CT, the current standard of assessment. Ultrasound provides a reliable, valid alternative to CT for obtaining an indication of the amount of humeral torsion in the upper extremity.

Validity of measuring humeral torsion using palpation of bicipital tuberosities

The magnitude of humeral torsion (HT) affects the internal and external rotation range of motion at the shoulder. Currently imaging is required to quantify the HT angle, however, factors such as cost and non-availability of imaging to musculoskeletal clinicians limits its use. The aim of this study was to examine the validity of palpation of the bicipital tuberosities as an alternative to imaging for quantifying HT angles. The bicipital-forearm angle, an indirect measure of HT, was measured using palpation and real-time ultrasound imaging in 25 subjects. The agreement among the two methods was excellent with the Intraclass Correlation Coefficient (3,k)  =  0.92, and the mean difference between the two methods was -0.2° (SD 4.1°) with 95% limits of agreement of -8.3° to 7.9°. Pearson's correlation coefficient (r) among the two methods was 0.85. In a clinical setting, palpation appears to be a practical alternative to US imaging for measuring HT.

Mechanisms of rotator cuff tendinopathy: intrinsic, extrinsic, or both?

The etiology of rotator cuff tendinopathy is multi-factorial, and has been attributed to both extrinsic and intrinsic mechanisms. Extrinsic factors that encroach upon the subacromial space and contribute to bursal side compression of the rotator cuff tendons include anatomical variants of the acromion, alterations in scapular or humeral kinematics, postural abnormalities, rotator cuff and scapular muscle performance deficits, and decreased extensibility of pectoralis minor or posterior shoulder. A unique extrinsic mechanism, internal impingement, is attributed to compression of the posterior articular surface of the tendons between the humeral head and glenoid and is not related to subacromial space narrowing. Intrinsic factors that contribute to rotator cuff tendon degradation with tensile/shear overload include alterations in biology, mechanical properties, morphology, and vascularity. The varied nature of these mechanisms indicates that rotator cuff tendinopathy is not a homogenous entity, and thus may require different treatment interventions. Treatment aimed at addressing mechanistic factors appears to be beneficial for patients with rotator cuff tendinopathy, however, not for all patients. Classification of rotator cuff tendinopathy into subgroups based on underlying mechanism may improve treatment outcomes.