Nonthrowing Shoulders Research Articles

Prevalence of Abnormal Findings in the Posterosuperior Humeral Head of Asymptomatic Collegiate Baseball Pitchers Using Ultrasonography

BackgroundThe posterosuperior humeral head contacts the glenoid during pitching. While magnetic resonance imaging (MRI) often detects abnormalities in the posterosuperior humeral head of baseball pitchers, ultrasonography may also be effective in identifying these abnormalities. However, studies on such abnormalities in asymptomatic players are limited. Thus, this study aimed to determine the prevalence of abnormal findings in the humeral head using ultrasonography in asymptomatic collegiate baseball pitchers. MethodsWe utilized ultrasonography to assess abnormal findings in the humeral head, defined as a break in continuity or an irregular surface around the infraspinatus insertion, in 33 college baseball pitchers (pitcher group) and 30 college students without experience in overhead sports (control group). For 11 of the 33 pitchers, computed tomography (CT)-like images were used to locate the abnormalities. The location was quantitatively identified in the axial plane using a clock system, with the bicipital groove designated as 12 o’clock, and qualitatively assessed in the sagittal plane. Shoulder internal and external rotation ranges of motion (IR and ER ROMs) and humeral retroversion were measured using an inclinometer. The prevalence of abnormalities among the four subgroups (throwing and non-throwing shoulders of the pitcher group and dominant and non-dominant shoulders of the control group) was compared using the Fisher’s exact test. A paired t-test was also performed to compare the IR and ER ROMs, as well as the humeral retroversion between each group’s throwing (dominant) and non-throwing (non-dominant) sides. ResultsThe prevalence of abnormalities was significantly higher (76%) in the throwing shoulder of the pitcher group than in the other shoulder groups (< .001). The mean position of the humeral head abnormalities in the axial plane was 8:32 ± 0:21 in the clock system, with all abnormalities located at the infraspinatus insertion on the greater tuberosity in the sagittal plane according to CT-like image analysis. While ER ROM and humeral retroversion were greater in the throwing shoulder, IR ROM was less than that in the non-throwing shoulder in the pitcher group (< .001). ConclusionUltrasonographic assessments revealed a higher prevalence of abnormalities in humeral head for asymptomatic collegiate baseball pitchers. Repetitive throwing motions may lead not only to adaptations in the ROM of the shoulder joint but also to abnormalities in the humeral head. Thus, ultrasonography may help identify asymptomatic baseball players with physiological internal impingement.

Kinematic Parameters Predictive of Pitch Velocity in Youth to Professional Baseball Pitchers: A Qualitative Systematic Review.

Specific kinematic factors have been found to contribute to faster pitch speeds, with poor mechanics leading to injury. To discuss the kinematic parameters that predict faster ball velocity among baseball pitchers. Systematic review. Using the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines, the authors utilized the Cochrane Database of Systematic Reviews, PubMed (2008-2019), and OVID/MEDLINE (2008-2019) databases. Eligible articles included those that reported on kinematic factors predictive of ball velocity across youth, high school, collegiate, and professional levels of play. The quality of all included studies was evaluated by 2 reviewers using the Appraisal tool for Cross-Sectional Studies (AXIS). The lack of consistent study design or outcome variables precluded meta-analysis. A total of 584 studies were identified from the initial search with 12 included in final analysis (930 pitchers in total; 429 [46.1%] youth, 164 [17.6%] high school, 153 [16.5%] collegiate and 184 [19.8%] professional) with mean ball velocity of 71.1 mph (114.4 km/h). The average AXIS score was 16 out of a possible 20. The shoulder played a significant role in the generation of velocity-induced torques. Hip and shoulder separation was associated with a 2.6 ± 0.5 mph (4.1 ± 0.8 km/h) increase in velocity, whereas increased shoulder movement of the nonthrowing arm was negatively correlated with initial ball velocity (r2 = 0.798). Furthermore, hip/shoulder separation, decreased movement of the nonthrowing shoulder, trunk power and timing of maximum trunk rotation, increased contralateral trunk tilt and increased sagittal-plane trunk tilt, and decreased knee flexion at ball release were all associated with higher fastball speeds. Multiple upper extremity and trunk kinematic parameters affect ball velocity, with significant contributions from the throwing shoulder and trunk, as well as nondominant arm. Understanding kinematic predictors of faster ball velocity can help guide training regimens.

Handball players have superior shoulder proprioception: a prospective controlled study

Proper proprioceptive and neuromuscular control is crucial for the overhead athlete's performance. The aim of the present study was to evaluate the shoulder joint position sense (JPS) levels in overhead throwing athletes. The secondary aim was to confront the proprioceptive abilities with glenohumeral adaptive changes and pathologies among athletes. Ninety professional handball players and 32 healthy volunteers were recruited. JPS levels were measured by an electronic goniometer and expressed as values of an active reproduction of the joint position (ARJP) and as error of ARJP (EARJP) in three different reference positions for each movement (abduction and flexion at 60°/90°/120°; internal (IR) and external rotation (ER) at 30°/45°/60°). Side-to-side differences revealed significantly better values of EARJP for the throwing shoulders in abduction at 90° and 120°, flexion at 90° and 120°, IR at 60° and in ER at 30° and 60° compared to the non-throwing shoulders. Handball players showed significantly better proprioceptive levels in their throwing shoulder compared to the dominant shoulder of the control group in abduction at 90° (p=0.037) and 120° (p=0.001), flexion at 120° (p=0.035), IR at 60° (p=0.045) and in ER at 60° (p=0.012). Handball players present superior shoulder JPS in their dominant throwing shoulder at high range of motion angles when compared to a non-athlete population and to their own non-dominant shoulder.

Increased external rotation related to the soft tissues is associated with pathologic internal impingement in high-school baseball players.

Changes in soft-tissue structures such as anterior laxity and posterior tightness are thought to contribute to the development of pathologic internal impingement in baseball players. Although side-to-side differences in shoulder rotational range of motion (ROM) is commonly used in clinical practice to quantify the soft-tissue changes, the ROM does not accurately reflect the soft-tissue changes because the ROM is affected not only by the soft tissues, but also by the bone. Increased retroversion of the humeral head is often observed in the dominant shoulder of throwing athletes. The purpose of this study was to determine the relationship between the soft-tissue-related (STR) ROM and pathologic internal impingement in baseball players. Bilateral humeral retroversion and ranges of glenohumeral external rotation (ER) and internal rotation (IR) were investigated in 81 high-school baseball players. The players were divided into two groups: the internal impingement group (19 players) and the control group (62 players). Humeral retroversion was measured using the ultrasound-assisted technique to assess the bone-related ER and IR. The STR ER and IR were defined as subtracting the amount of humeral retroversion from the measured ER andIR. The side-to-side difference (throwing shoulder-nonthrowing shoulder) in humeral retroversion showed no significant difference between the internal impingement group (6°±10°) and control group (11°±11°) (P=.064). The side-to-side difference in STR ER was significantly greater in the internal impingement group (12°±12°) than that in the control group (1°±14°) (P=.002). No significant difference was observed in the side-to-side difference in STR IR between the internal impingement group (-7°±16°) and control group (-5°±15°) (P=.696). Pathologic internal impingement was significantly associated with the side-to-side difference of STR ER (odds ratio, 1.06 for increase of 1°; 95% confidence interval, 1.02-1.11; P=.008). In high-school baseball players, the increased STR ER in the throwing shoulder may be associated with pathologic internal impingement. An increase of 10° in side-to-side difference in STR ER would increase the risk of pathologic internal impingement by 1.8 times.

Shoulder Injuries in Professional Baseball Batters: Analysis of 3,414 Injuries Over an 8-Year Period

PurposeTo characterize the shoulder injuries experienced by baseball batters and position players (nonpitchers); to quantify the outcomes of these injuries with respect to time out of play, recurrence, and surgery rates; and to identify any injury patterns that are associated with worse outcomes.MethodsBetween 2011 and 2017, all Major League Baseball (MLB) and Minor League Baseball (MiLB) players who sustained shoulder injuries were identified using the MLB Health and Injury Tracking System (HITS). Injuries were included if they were sustained during baseball activity, resulted in at least 1 day missed (DM), and occurred in position players (nonpitchers).ResultsOver the study period, a total of 3,414 shoulder injuries occurred in batters, resulting in a sum of 68,808 DM and a mean of 22 DM per injury. Most injuries were a result of acute trauma (n = 2125; 62.2%) with throwing as the predominant activity (n = 1292; 38%). Rotator cuff strain/tears was the most common diagnosis (n = 790; 23.1%), and SLAP tears had the highest season-ending rate (35.3%) and need for surgery (45.1%). There was a lower frequency of surgery (6.2% vs 9.2%; P = .002) and reinjury (2.03% vs 3.62%; P = .007) in the throwing shoulder vs the nonthrowing shoulder. There was an increased frequency of surgery for the front versus the back batting shoulder (8.2% vs 6.2%; P = .031) with similar DM (20.7 vs 22.2; P = .333) and return to play rates (94.0% vs 92.2%; P = .135).ConclusionsDuring the 7-season study period, there were a total of 3,414 shoulder injuries that resulted in nearly 70,000 days of out of play in professional baseball position players/batters (nonpitchers). Although pitchers were intentionally excluded from the analysis, throwing was still the most common mechanism of injury, and rotator cuff injuries were the most common injury. Labral tears were the most likely injury to be season ending and require surgery.Clinical RelevanceThis study is meant to help determine characteristics of shoulder injuries that occur in non-pitchers by focusing on professional baseball batters and position players. This information could be helpful to sports medicine practitioners and shoulder specialists to better prognosticate injury recovery.

Range of motion and muscle function on shoulder joints of young handball athletes.

The detection of primary risk factors through the assessment of shoulder range of motion (ROM) and muscle function could prevent injuries in the initial stages of the handball (HB) practice. To compare shoulder ROM, muscle strength and muscle extensibility between throwing and non-throwing shoulders in young HB athletes and between non-HB athletes. A cross-sectional study was designed. Participants aged between 14-16 years that practice physical activity regularly were included and divided in two groups. The HB group included volunteers who practiced HB, the control group included volunteers who practiced other activities. The variables measured were internal rotation and external rotation ROM, maximum isometric strength, and extensibility of the tissues of the posterior part of the throwing and non-throwing shoulder. Thirty-seven subjects were included. The HB group (n= 19) showed greater ROM in both shoulders compared to the control group (n= 18) (p< 0.05). The throwing shoulder of the HB group showed less internal rotation ROM, greater external rotation ROM and greater internal rotation strength when compared to the non-throwing shoulder (p< 0.05). The results of the study suggest that young HB athletes present differences in shoulder ROM compared to non-HB athletes. Also, HB athletes showed differences in ROM and strength between the TS and non-TS. Hence, the assessment of the shoulder ROM and muscle function should be taken into consideration to avoid injuries in this population.

Return to Play in Adolescent Baseball Players after SLAP Repair (131)

Objectives:Superior labrum from anterior to posterior (SLAP) tears are increasingly common shoulder injuries in adolescent athletes who participate in repetitive overhead throwing. The purpose of this study is to evaluate adolescent baseball athletes who undergo SLAP repair in order to determine their long-term progression of play, surgical outcomes, and overall satisfaction with surgery.Methods:Patients between the ages of 10-19 who underwent a SLAP repair over a 10-year period from 2008-2018 with minimum two year follow-up were identified by a database query in the medical records of a single institution. From this cohort, non-baseball athletes and injuries to non-throwing shoulders were excluded. After identifying the cohort, patients were contacted via phone to complete functional outcome scores including Conway Score, Western Ontario Shoulder Instability (WOSI) Index, Kerlan-Jobe Orthopedic Clinic (KJOC) Shoulder and Elbow Score, Short Form 12 Mental (MCS)/Physical (PCS) survey and a custom return to play questionnaire.Results:During this time period, 59 baseball players met the inclusion criteria for this study and 76.3% (45/59) of patients were available to be contacted to complete final follow-up surveys at a minimum of 2 years. All patients were male with a mean age of 17.4 +/- 1.5 (14-19) years. The mean follow-up of this cohort was 5.3 +/- 2.6 (2.1-12.1) years. The overall return to play rate was 75.6% (34/45). The average time from surgery to initiation of throwing was 5.9 +/- 2.0 (2-12) months and the average time to return to full competition was 11.3 +/- 3.5 (6-22) months after the surgery. After the SLAP repair, those who returned to play continuing playing baseball competitively for 3.0 +/- 1.9 (0.5-8.0) years after surgery. At the time of final follow-up, 71.1% (32/45) of players had stopped playing baseball. Of those who had stopped playing competitive baseball, 12 (37.5%) reported it was because they were not recruited to the next level, 10 (31.3%) reported they lost the desire to play and 10 (31.3%) reported their shoulder prevented them from playing. The overall mean KOJC, WOSI, SF-12 MCS and SF-12 PCS scores were 60.0 +/- 27.4 (range, 0-100), 21.0+/-20.6% (0-73.8%), 55.2+/-3.9 (37.4-59.8) and 55.2+/-5.6 (range, 37.9-65.7) respectively. The overall satisfaction score was 83.2% with 86.7% (39/45) saying they given the opportunity they would undergo surgery again.Conclusions:The results of this study demonstrated a low return to play rate and low patient reported outcomes on baseball specific surveys among adolescent baseball players who underwent a SLAP repair. Mean functional outcome scores between pitchers and position players were not found to be significantly different. Based on these findings, orthopedic surgeons can better counsel their adolescent baseball players on expectations for future return to play and functional outcomes after SLAP repair.

Relaciones entre la extensibilidad, el rango de movimiento y la intensidad del dolor en jugadores de balonmano semiprofesionales

ObjectiveTo compare range of motion and extensibility between the throwing shoulder and non-throwing shoulder in handball athletes. To investigate the relationship between the time practicing handball with the extensibility, the range of motion (ROM) and shoulder pain intensity during throwing actions. MethodsA cross-sectional study was carried out. Forty-three semi-professional handball athletes were included. The time practicing handball, the extensibility of the tissues of the posterior part of the shoulder, the internal rotation and external rotation ROM and pain intensity during throwing actions were assessed. ResultsThe throwing shoulder presented a decreased in internal rotation ROM and extensibility of the tissues of the posterior part of the shoulder (P<.05), and a greater external rotation ROM (P=.044). Moderate negative associations were found between the time practicing handball and internal rotation ROM (P=.011) and the extensibility of the tissues of the posterior part of the shoulder (P=.033). A positive moderate association was found between internal rotation ROM and extensibility of the tissues of the posterior part of the shoulder (P=.002). No associations were found with pain intensity (P>.05). ConclusionsThe throwing shoulder presents a lesser internal rotation ROM, a greater external rotation ROM and a lack of extensibility. The internal rotation ROM deficit has been associated with the extensibility, and both variables have been associated with the time of practicing handball.

The throwing shoulder in youth elite handball: adaptions of inferior but not anterior capsule thickness differ between the two sexes

ABSTRACT The aim was to investigate side-to-side and sex differences of anterior and inferior capsule thickness (ACT, ICT) between the throwing and non-throwing shoulder (TS, NTS) in youth elite handball players. 125 youth female and male elite handball players (14.1±0.7yo) were assessed for ACT and ICT by ultrasound . ACT measurement was performed from anterior (3 o’clock) in upright position and for ICT from inferior (6 o’clock) in supine position. Measurements of ICT in the TS of all athletes (1.4±0.2 mm) differed significantly but marginally to those in the NTS (1.3±0.2 mm) (p = 0.001). Female (1.2±0.2 mm vs. 1.3±0.2 mm; p = 0.007) but not male youth players (1.4±0.2 mm vs. 1.4±0.2 mm, p = n.s.) demonstrated slight differences in ICT in the TS compared with the NTS. Although significant, the thickness in the TS compared to the NTS was within the measurement accuracy of the ultrasonic assessment. No difference in ACT was observed in the TS (1.4±0.3 mm) compared to the NTS (1.4±0.3 mm) for both sexes (n.s.). In conclusion, the anterior and inferior capsule thickness in youth elite handball athletes is not or only marginally different between throwing and non-throwing shoulders.

Shoulder Strength and Closed Kinetic Chain Upper Extremity Stability Test Performance in Division III Collegiate Baseball and Softball Players.

BackgroundShoulder strength measured with a handheld dynamometer (HHD) and the Closed Kinetic Chain Upper Extremity Stability Test (CKCUEST) are clinical tools that have been used to measure athlete’s performance and track their progress.PurposeThe specific aims of this study were to describe baseball (BB) and softball (SB) players isometric strength measures and their performance on the CKCUEST; examine the relationships between strength and the CKCUEST; compare isometric strength measures of the throwing and non-throwing arms; and compare the strength and the CKCUEST measures between BB and SB players.Study DesignObservational cohort study.MethodsParticipants included 50 DIII BB and 24 DIII SB players. Shoulder strength for the internal and external rotators were measured using a HHD and the CKCUEST was performed. The CKCUEST score and power were calculated. Descriptive statistics and paired t-tests were used to compare throwing and non-throwing shoulder strength. Independent t-test was used to compare BB and SB players shoulder strength and the CKCUEST measures.ResultsThe BB players demonstrated significant strength differences between the throwing and non-throwing shoulders and the internal rotators were significantly stronger than the external rotators (p < 0.05), while the strength ratio of the internal and external rotators was not different between arms (p=0.87). The SB players demonstrated no significant strength differences between the throwing and non-throwing shoulders for the internal and external rotators or the strength ratio of the rotators (p > 0.05). There were no significant differences between the strength of the internal and external rotators of the non-throwing shoulder (p=0.075) or the throwing shoulder (p=0.096). The BB players throwing and non-throwing shoulders produced significantly more internal and external force than the SB players (p < 0.001), however, the internal/external rotators strength ratio were similar (p=0.32, p=0.30). The CKCUEST power had inverse and significant correlations (p=0.006, p=0.003) with SB players internal and external rotators, respectively. The CKCUEST power was significantly different between BB and SB players (p < 0.001).ConclusionThis study presented shoulder rotator strength and CKCUEST reference values for DIII BB and SB players. BB players demonstrated more strength but overall, less symmetry compared to SB players. CKCUEST power may be considered for the evaluation of athletes.Level of EvidenceLevel III

The Area of Impingement in the Throwing Versus Nonthrowing Shoulder of Collegiate Baseball Players: An MRI Study of the Simulated Late-Cocking Phase of Throwing.

Background:During shoulder abduction and external rotation, internal impingement can occur when compressive forces between the greater tuberosity and the posterior glenoid rim pinch the undersurface of the rotator cuff. Previous studies on internal impingement have focused on qualitative results such as pathological findings; however, few studies have quantified the area of impingement (AOI) of the rotator cuff muscles between the greater tuberosity and the posterior glenoid rim.Purpose:To compare the AOI between the throwing and nonthrowing shoulders of baseball players.Study Design:Controlled laboratory study.Methods:A total of 14 asymptomatic male collegiate baseball players participated in this study. The AOI in both the throwing and the nonthrowing shoulders was calculated using magnetic resonance imaging (MRI) scans. The MRI measurements were collected with the shoulder at 90° of abduction and at 90° and 100° of external rotation. The area, width, and depth of impingement as well as cystic changes in the greater tuberosity and degeneration in the posterior labrum were compared between the throwing and nonthrowing shoulders.Results:The AOI was significantly greater in the throwing shoulders than in the nonthrowing shoulders (90° of external rotation: 32.4 vs 19.1 mm2, respectively; 100° of external rotation, 28.0 vs 15.6 mm2, respectively; P < .001 for both). Compared with the nonthrowing shoulders, there were more positive findings in the throwing shoulders regarding greater tuberosity cystic changes (0 vs 7, respectively; P = .006) and posterior labral degeneration (3 vs 13, respectively; P < .001).Conclusion:The AOI and the number of lesions in the greater tuberosity and posterior labrum were greater in throwing shoulders than in nonthrowing shoulders. Therefore, damage to the insertion of the rotator cuff muscles may affect internal impingement.Clinical Relevance:Lesions in the greater tuberosity and posterior labrum in throwing shoulders may increase the AOI by expanding the joint gap behind the glenohumeral joint. Impingement of the greater tuberosity and the posterior glenoid rim may lead to rotator cuff tears.

Correlation of glenohumeral internal rotation deficit with shear wave ultrasound elastography findings for the posterior inferior shoulder capsule in college baseball players

The glenohumeral internal rotation deficit (GIRD), primarily caused by the tightness of the posterior capsule, is a major risk factor for shoulder injuries in overhead throwing athletes. Quantitative evaluation of posterior capsular thickness and tightness can help determine the relationship between the posterior inferior capsule and GIRD. One previous study has assessed posterior capsule tightness using shear wave elastography (SWE), in college baseball players; however, it did not address the cutoff value of capsular elasticity that could be considered as abnormal capsular tightness. We aimed to re-evaluate effectiveness of SWE in quantifying posterior shoulder capsule tightness in college baseball players and determine the cutoff value of abnormal capsular elasticity that can predict impending throwing-related shoulder injuries associated with GIRD. Twenty-four college baseball players were enrolled in this study. External and internal rotation of the shoulder joint was assessed. The participants were classified into the GIRD group if their throwing shoulder showed >20° of internal rotation loss compared with their nonthrowing shoulder. In a longitudinal ultrasonographic scan of the posterior inferior capsule, shear wave (SW) velocity and thickness were measured at the point nearest to the labrum on both shoulders. Of the 24 subjects, 6 had a GIRD. The mean value of the SW velocity in the throwing shoulder was greater in the GIRD group than in the non-GIRD group (P = .006). The SW velocity difference between the throwing and nonthrowing shoulder was also greater in the GIRD group than in the non-GIRD group (P < .001). There was no significant difference in the thickness of the posterior inferior capsule between both groups. In correlation analysis, the difference in the SW velocity was more strongly correlated with the GIRD than with the SW velocity in the throwing shoulder. When we assume that a 20° GIRD is indicative of a shoulder at risk, the cutoff SW velocity in the throwing shoulder is 4.81 m/s and the SW velocity difference is 0.77 m/s. The SW velocity is closely associated with posterior shoulder capsular tightness and may be of quantitative value in baseball players.

Loss Of Glenohumeral Range Of Motion And Its Effects On Eccentric Strength In Intercollegiate Pitchers

Deficits in glenohumeral joint rotational range of motion (ROM) and strength in baseball pitchers’ shoulders have been linked to increased risk of musculoskeletal injury. Total arc of motion deficit (TAMD) is an objective parameter that involves the comparison of bilateral shoulder internal rotation (IR) and external rotation (ER) ROM values as a measure of soft tissue changes at that joint. PURPOSE: To determine whether TAMD in the throwing shoulder, when compared to the non-throwing shoulder, affected the eccentric strength of IR and ER muscles of the glenohumeral (GH) joints of intercollegiate baseball pitchers. METHODS: 47 male pitchers (age, 19.8+1.2 yrs; hgt, 183.9+5.5 cm; mass, 85.7+10.2 kg; pitching experience, 9.9+2.8 yrs) were recruited to this study and assigned to 1 of 2 groups: 24 pitchers with >10° side-to-side differences in total rotational motion were assigned to the TAMD group, while 23 pitchers with less than 10° side-to-side ROM differences qualified for a non-deficit group (Non-TAMD). We measured eccentric IR and ER peak torques at 300o/sec bilaterally with an isokinetic dynamometer. RESULTS: We observed higher ER/IR strength ratios of the dominant arms when compared to the non-dominant arms of pitchers in both the TAMD (85.2%+24.3% and 45.4%+7.3%) and non-TAMD groups (87.3%+22.8% and 48.5%+8.1%) (p<0.001). There were no significant differences between the normalized TAMD and non-TAMD dominant arm eccentric IR torques (0.497+0.073 Nm/kg BW vs. 0.478+0.062 Nm/kg BW) or eccentric ER torques (0.407+0.082 Nm/kg BW vs. 0.411+0.077 Nm/kg BW) (p>0.05). Dominant arm eccentric ER/IR strength ratio (86.2%±23.3% vs. 47.0%±7.8%) and ER eccentric peak torque (0.410±0.088 Nm/kg BW vs. 0.295±0.049 Nm/kg BW) were both significantly greater than in the non-dominant arm (p<0.05). Internal rotation eccentric peak torque (0.488±0.088 Nm/kg BW vs. 0.636±0.101 Nm/kg BW) was significantly higher in the non-dominant arm (p<0.05). CONCLUSIONS: We found ER/IR ratios that were significantly higher in the dominant arms, but no significant differences in ER or IR eccentric strength between the TAMD and Non-TAMD groups. Loss of shoulder rotation ROM did not have a significant effect on the production of IR and ER eccentric torques at the GH joint in this sample of intercollegiate pitchers.

Increased posterior shoulder capsule thickness in youth elite handball players: a sonographic investigation

Range of motionadaptations in the shoulders of overhead throwing athletes have been reported, but knowledge about the development of soft-tissue adaptations is limited. The purpose of this study was to investigate differences in posterior shoulder capsule thickness and internal rotation between the throwing and non-throwing shoulder. On the basis of the sample size calculation, we assessed 63 youth elite handball players (33 boys and 30 girls, mean age: 13.6 ± 0.9 years) for glenohumeral internal and external rotational range of motion, humeral retrotorsion, and posterior capsule thickness (PCT) with a manual goniometer and a portable ultrasound device and calculated sports-specific differences between the throwing and non-throwing shoulder as well as correlations with PCT. Youth handball players showed side-to-side differences in internal rotation, external rotation, and humeral retrotorsion between the throwing and non-throwing shoulder. Posterior shoulder capsules were 1.21 times thicker (95% confidence interval: 1.1-1.3) in the throwing shoulder than in the non-throwing shoulder (1.3 ± 0.3 mm vs. 1.2 ± 0.2 mm, P < .0001). Loss of internal rotation did not correlate with PCT. In youth elite handball athletes, posterior shoulder tightness and subsequent sports-specific loss of internal rotation in the throwing shoulder are not related to PCT. Thus, in this age class, other (soft-tissue) factors must be responsible for this condition.

Pitching shoulder passive flexibility: torque-angle analysis for external rotation and internal rotation

ABSTRACT In this study, a custom device was developed to analyse the pitching shoulder’s external rotation (ER) and internal rotation (IR) passive flexibility. We analysed three novel measures: the resistance onset angle (ROA = angle where the shoulder begins stretching), rotational stiffness, and torque at the end range of motion (ROM). The purpose was to conduct a bilateral analysis to determine if there are significant differences between the throwing and non-throwing shoulder. Participants were 30 upper level pitchers (13 division I, 17 minor league). During testing, pitchers laid supine on a treatment table and the arm was secured to a rotational wheel with the shoulder abducted 90° and elbow flexed 90°. Dependent t-tests revealed significant (p < 0.01) and relatively extreme bilateral differences for all three variables. The throwing shoulder had: increased ER ROA (9°), decreased IR ROA (5.3°), increased ER stiffness (17%), increased IR stiffness (34%), increased ER torque (21%), and increased IR torque (30%). Secondary correlation analysis was completed to determine if the torque-angle variables were good predictors of the end ROM. Stiffness correlations were weak for ER (r = 0.35, p = 0.048) and IR (r = 0.42, p = 0.017) but ROA correlations were strong for ER (r = 0.85, p < 0.001) and IR (r = 0.86, p < 0.001).

SHOULDER RANGE OF MOTION CHARACTERISTICS IN DIVISION III COLLEGIATE SOFTBALL AND BASEBALL PLAYERS

Adaptive changes may occur to the throwing shoulder of overhead athletes that can influence range-of-motion (ROM). Shoulder ROM characteristics of Division III softball (SB) and baseball (BB) players are unique. To report the passive ROM characteristics of Division III SB and BB players and identify similarities and differences between these two populations. Descriptive, observational research on measurement. Participants included healthy Division III BB (n = 50) and SB (n = 24) players. Passive shoulder internal rotation (IR) and external rotation (ER) ROM were measured in the supine position with the arm in 90 ° of abduction and the scapula stabilized. Descriptive statistics and frequency distributions were used to describe ROM. Paired and independent t-tests were also used to compare throwing and non-throwing shoulder ROM for athletes of each sport and to compare the shoulder ROM of SB and BB players, respectively. The IR and ER ROM for BB players throwing shoulders (IR 54.1 ± 10.9 °; ER 94.1 ± 9.1 °) were significantly different (p < 0.001) from their non-throwing shoulders (IR 63.3 ± 11.1 °; ER 87.6 ± 9.2 °) while SB players were not (p = .06 & .08, respectively). Compared to the BB players, the throwing shoulder of SB players demonstrated statistically significantly higher IR ROM (p < .001, mean difference = 11.8 °, 95% CI: 6.4-17.2 °) as well as higher total range of motion (TRM) (p < .001, mean difference = 14.4 °, 95% CI: 8.6-20.2 °) when compared to BB players. Glenohumeral internal rotation deficit (GIRD) was significantly higher in BB players when compared to SB players (p = .042, 95% CI: .2-10.8 °). There were no significant differences in IR, ER, TRM, GIRD and ER gain between SB or BB pitchers and all other field positions (p > .05). SB players have more ROM and bilateral symmetry when compared to BB players. TRMD occurred more often than GIRD in BB players, indicating that they did not adaptively gain the same amount of ER while losing IR. The throwing shoulder ROM characteristics of both SB and BB players in this study were not influenced by the player's position (pitcher vs. field player). Level III.

Age-related changes in muscle elasticity around the shoulder joint in young male baseball players: A prospective longitudinal study

BackgroundLongitudinal changes of elasticity in the muscle tissues around the shoulder joint during the growth period have not been assessed using shear wave elastography. MethodsThis study enrolled male students aged 13–18 years who played baseball or rubber baseball as an extra-curricular activity during junior high or high school or on a baseball team outside of school. The exclusion criterion was a history of surgery for athletic injury. One hundred and twenty-one boys were included in the study. The elasticity of the superior part of the trapezius, the supraspinatus, and the infraspinatus were measured by ultrasound. The shear elastic modulus (SEM), which is the ratio of the strain ratio (SR) in the acoustic coupler to the SR of each muscle, was calculated as a representative value. Six months after the baseline assessment, subjects were evaluated regarding any newly developed pain in the joint of the throwing shoulder, and categorized into either the non-pain group or the pain group. ResultsAlthough all muscle SEMs tended to increase in both the throwing and non-throwing shoulders, no significant difference was observed in the prevalence of shoulder joint pain between ages (p = 0.541). The results of a binominal logistic regression analysis, adjusted for age, body mass index, playing position in baseball, frequency of baseball practice, shoulder range of motion, and muscle strength showed that a decrease in SEM values of the supraspinatus was a risk factor for the development of new pain (odds ratio: 0.056; 95% confidence interval 0.011–0.299; p = 0.001). ConclusionsThe elasticity of muscle tissues around the throwing shoulder increased with age, and low tissue elasticity of the supraspinatus of the throwing shoulder was a factor that triggered pain during throwing motions.

The throwing shoulder in youth elite handball: soft-tissue adaptations but not humeral retrotorsion differ between the two sexes.

In youth handball players, knowledge about the development of soft-tissue adaptation and humeral retrotorsion is limited. The purpose of this study was to investigate differences in adaptations in the glenohumeral rotational range of motion and humeral retrotorsion of the throwing arm between male and female youth elite handball players. One-hundred and thirty-eight youth elite handball players (mean age: 14.1 ± 0.7years) were assessed for glenohumeral external (ER) and internal (IR) rotational ranges of motion and humeral retrotorsion (HRT) by means of a manual goniometer and a portable ultrasound device. Sports-specific adaptations between the dominant and non-dominant shoulders and between male and female adolescents were calculated. Handball players showed side-to-side differences in IR and ER in the throwing shoulder. HRT did not correlate with the measurements of rotational ROM of the throwing arm. Male athletes showed a more pronounced glenohumeral internal rotation deficit than female athletes (13.1° ± 22.8° vs. 5.1° ± 14.0°, p = 0.014). Adaptations in HRT but no sex differences could be seen in the throwing shoulder (16.5° ± 9.6°) compared to the non-throwing shoulder (13.5° ± 9.4°, p < 0.001). Loss of internal rotation and gain in external rotation in youth handball players seem to be more related to adaptive changes in the soft-tissues than to HRT. Male athletes showed stronger throwing-related adaptations in the rotational range of motion but not in humeral torsion in their dominant shoulder than female athletes. Cross-sectional study, Level II.

BASEBALL PLAYERS DIAGNOSED WITH ULNAR COLLATERAL LIGAMENT TEARS DEMONSTRATE GREATER SIDE TO SIDE DIFFERENCES IN PASSIVE GLENOHUMERAL ABDUCTION RANGE OF MOTION COMPARED TO HEALTHY CONTROLS.

Numerous studies have shown that baseball players develop range of motion adaptations in their throwing arm. While some of these shoulder range of motion adaptations can lead to greater throwing velocity, excessive changes in shoulder range of motion can increase the risk of injury to the ulnar collateral ligament (UCL). The purpose of this study was to compare the passive GH-ABD ROM measures of baseball players with a diagnosed UCL tear (UCL group) to a group of age, activity, and position matched healthy controls (CONT group). The primary hypothesis was that baseball players with an UCL tear would have a greater loss of passive glenohumeral abduction range of motion in their throwing shoulder than healthy controls. A secondary hypothesis was that baseball players with an UCL tear would demonstrate similar glenohumeral abduction range of motion in their non-throwing arm and increased side-to-side glenohumeral abduction differences compared to the healthy cohort. Retrospective prospective case-control study. The UCL group had significantly greater glenohumeral abduction range of motion on their throwing shoulder (132.5 °±8.3 °) than the CONT group (120.19 °±11.2 °, p = 0.000). Similarly, the UCL group had increased glenohumeral abduction range of motion on their non-throwing shoulder (141.2 °±9.5 °) compared to the CONT group (124.1 °±11.4 °, p = 0.000). Additionally, the UCL group had a greater glenohumeral abduction difference (-8.7 °±8.4 °) than the CONT group (-3.8 °±7.7 °, p = 0.001). In contrast to the original hypotheses, high school and collegiate baseball players that sustained an UCL injury presented with greater glenohumeral abduction range of motion in both their throwing and non-throwing shoulders compared to healthy controls. However, the finding of greater side-to-side glenohumeral abduction range of motion deficits in the UCL group when compared to the matched healthy controls confirms the secondary hypothesis. Level 3.

Strength and Motion in the Shoulder, Elbow, and Hip in Softball Windmill Pitchers.

Softball pitching is a ballistic, complex movement that requires an underhand windmill motion to create force and ball velocity. In addition to proper pitch biomechanics, upper and lower extremity strength and joint motion likely contribute to ball location accuracy and velocity. Yet, the number of studies reporting muscle strength and joint range of motion among softball pitchers is scarce. To assess differences between throwing and nonthrowing shoulder, elbow, and hip (lead and trail leg) strength and range of motion (ROM) in high school and collegiate level softball windmill pitchers. Cross-sectional study. Thirty-three female softball pitchers (24 high school, 9 collegiate) were recruited from local teams. Goniometric joint ROM and handheld dynamometer strength measurements of the bilateral shoulders, elbows, and hips were measured. Goniometric joint ROM of the bilateral elbows (flexion, extension), shoulders, and hips (flexion, extension, internal rotation [IR], external rotation [ER]). Handheld dynamometer strength measurements of the bilateral shoulders (flexion, extension, abduction, IR, ER), elbows (flexion, extension), and hips (flexion, extension, IR, ER, abduction). Across all pitchers, there was greater shoulder flexion ROM in the nonthrowing limb than in the throwing limb (P = .004). There was greater hip extension in the lead leg than trail leg. Among high school pitchers, there was greater shoulder ER (x = 105.792 ± 7.11) than collegiate pitchers (x = 100.1 ± 6.92), P = .05. There was no difference in total arc of shoulder rotational motion (ER+ IR) between throwing and nonthrowing limbs across all pitchers, nor between high school and collegiate pitchers. Strength measures demonstrated greater throwing limb shoulder abduction (P = .006) and IR strength (P = .001) than the nonthrowing shoulder across all pitchers. Elbow flexion strength was significantly greater than the nonthrowing side (P = .001). No difference was noted in hip strength between lead and trail lower extremities. Developing normative data for softball pitchers upper and lower extremity strength and range of motion may allow providers to assess players more comprehensively and identify athletes out of the expected value range. This information may help in guiding strength and conditioning programs for softball pitchers. III.