Nondominant Shoulder Research Articles

Neck Range of Motion Prognostic Factors in Association to Shoulder and Elbow Injuries in Professional Baseball Pitchers

BackgroundAuthors have observed an association between cervical spine mobility and arm injury risk in baseball player; however, there is a need to assess the generalizability of cervical measurement data. Assessing the downstream of associations of cervical dysfunction on shoulder and elbow injuries can inform clinical interventions to help reduce future arm injuries. The purpose of this study was to assess the generalizability of neck range of motion measures as arm injury prognostic factors in professional baseball pitchers. MethodsA prospective cohort of professional baseball pitchers in one Major League Baseball Organization was performed. Pitchers underwent pre-season neck range of motion including cervical flexion, extension, rotation, lateral flexion, and the flexion-rotation test (CFRT) and were followed for the season. The outcome was the occurrence of shoulder or elbow injury. A Cox proportional hazards analysis was performed and reported as hazard ratios (HR) with 95% confidence intervals (95% CI). ResultsA total of 88 pitchers were included (Age: 24.2 (2.4); Left-Handed: 21 (23%); Fastball Velocity: 92.3 (1.8)), with 15,942 athlete exposure days collected over the season. Pitcher neck range of motion was assessed (Flexion: 64 (10); Extension: 69 (11); Difference in Lateral Flexion: -1 (7); Difference in Neck Rotation: -2 (9); Difference in CFRT: -1 (7)). A total of 20 arm injuries (Shoulder: 9 (10%); Elbow: 11 (13%); Combined Rate: 1.3 (95% CI: 0.7, 1.7) per 1000 exposure days) were suffered by pitchers during the season. For every degree increase in the difference in dominant (rotating to dominant shoulder) versus non-dominant (rotating to non-dominant shoulder) neck rotation, there was a four-fold increase in arm injury hazard (HR: 4.0 (95% CI: 1.1, 13.9), p = 0.031). No other neck measurements demonstrated prognostic value. ConclusionsA deficit in dominant versus non-dominant neck rotation was prognostic for pitching arm injury. However, the cervical rotation test did not have prognostic value in this sample. Further research is required to assess the generalizability and scalability of neck range of motion assessment in relation to baseball shoulder and elbow injuries across different competition levels.

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.

Chronic Adaptation of the Coracohumeral Space and Subscapularis Tendon in Professional Baseball Pitchers.

Pitchers frequently experience anterior shoulder pain, possibly associated with coracohumeral impingement; however, whether the coracohumeral distance (CHD) and/or subscapularis tendon adapt chronically (bilateral difference) due to pitching, and whether clinical measures are associated with CHD and subscapularis tendon organization have not been evaluated in professional pitchers. The authors hypothesized that dominant arm CHD would be smaller than the nondominant arm, dominant subscapularis tendon would have increased spatial frequency (ie, be more disorganized), and humeral retroversion (HR) would predict CHD and subscapularis tendon organization. Level 4. Healthy professional baseball pitchers were recruited during their preseason physical examination. Bilateral diagnostic ultrasound measured CHD, HR, and posterior capsule thickness (PCT), and quantified subscapularis tendon organization. External rotation, neutral, and crossbody CHD was measured. Overall, 52 healthy professional baseball pitchers participated. The dominant arm of pitchers demonstrated a significantly narrower CHD in all 3 positions (P < 0.01), increased scapular protraction (163 vs 156 mm; P < 0.01), and increased spatial frequency of the subscapularis tendon (1.8 vs 1.6 peaks/mm; P < 0.01). HR was associated with CHD in 30° of external rotation (R2 = 0.12; P < 0.01), neutral rotation (R2 = 0.11; P < 0.01), and the crossbody position (R2 = 0.28; P < 0.01). PCT was associated with CHD in 30° of external rotation (R2 = 0.16; P = 0.05). HR and CHD in 30° of external rotation was associated most strongly with subscapularis tendon organization (R2 = 0.11; P = 0.03). The dominant shoulder of professional pitchers presents with a smaller CHD, more scapular protraction, and more subscapularis tendon disorganization than the nondominant shoulder. Professional pitchers demonstrate chronic CHD and subscapularis tendon adaptations, which may increase their risk for anterior shoulder pain and subscapularis tendon injury.

Increased humeral retrotorsion is not a risk factor for overuse injury of the throwing shoulder in elite youth handball athletes

PurposeTo identify the potential role of humeral retrotorsion (HRT) and range of motion (ROM) as a risk factor for shoulder overuse injury in elite youth handball players. The hypothesis was that increased HRT is associated with an increased risk of shoulder overuse injury. MethodsOver two seasons, 258 elite youth handball players (52% boys; age:14±0.8years) were included. Pre-season assessment included HRT and glenohumeral internal (IR) and external (ER) rotational ROM using ultrasound and a manual goniometer. Sports-specific adaptations between male and female athletes and the dominant and nondominant shoulder were calculated. In addition, players completed standardized questionnaires over the 2018-2019 or 2019-20 season and reported any shoulder overuse symptoms using the Western Ontario Shoulder Index questionnaire. ResultsComparing male and female players showed significantly decreased HRT and decreased internal ROM in the dominant side of male athletes (p≤0.027). No other difference was found. Significant side-to-side differences between the dominant and non-dominant shoulder were found for HRT, IR, and ER, regardless of sex (p<0.001). For total range of motion (TROM), only female athletes showed a significant increase in the dominant arm (p=0.032). The dominant side showed a significantly higher glenohumeral internal rotation deficit (GIRD) in male athletes than in female athletes (10°±17° vs. 5°±10°, p=0.011). Adaptations in HRT, ER gain, and TROM gain were not significant. Over the course of the two seasons, 20 athletes reported shoulder overuse injuries. Although GIRD was borderline non-significant (p=0.056), none of the parameters tested were significantly associated with shoulder overuse injuries. ConclusionDespite significant side-to-side differences and sport-specific adaptations, individual pre-season screening of humeral retrotorsion and soft tissue adaptations does not identify elite youth handball athletes at increased risk of shoulder overuse injury.

Association Between Dominant-Shoulder Internal-Rotation Restriction and Low-Back Pain in Elite Male High School Soft Tennis Players.

The incidence of low-back pain (LBP)is high among elite male high school soft tennis players. A previous report showed that hip internal-rotation (IR) restriction in the non-dominant leg could increase the risk of LBP. Moreover, IR in the dominant shoulder is important for serve and stroke movements, suggesting that IR restriction in the dominant shoulder can contribute to LBP. The simultaneous incidence of non-dominant-hip IR restriction may help in developing a good LBP-related factor model; therefore, this study aimed to investigate the association between dominant-shoulder IR restriction and LBP in elite male high school soft tennis players. This is a single-center cross-sectional study. This study included 176 male high school soft tennis players from 14 elite teams. The main measures were IR and external-rotation range of motion (ROM) in the dominant and non-dominant shoulders and hip, assessed using a goniometer with a bubble attached. Multiple logistic regression analyses were performed with the presence of LBP as a categorical variable (LBP, 1; non-LBP (NLBP), 0). Multiple logistic regression models were created as follows: Model 1 included dominant-shoulder IR restriction (loss of glenohumeral IR (GIRLoss)), Model 2 included non-dominant-hip IR ROM, and Model 3 included both GIRLoss and non-dominant-hip IR ROM as the main explanatory variables to test the association between dominant-shoulder IR restriction and LBP, compare its suitability as an associated factor with non-dominant-hip IR restriction, and determine if either or both should be considered in an LBP association model based on model fit. The significance of each multiple logistic regression model was examined using the model χ2 test, and a model with P<0.05 was judged as a significant model. Model fit was examined using the Hosmer-Lemeshow test, and P≥0.05 was judged as a good model fit. The Akaike Information Criterion (AIC) and Bayesian Information Criterion (BIC) were used to compare the goodness-of-fit among multiple logistic regression models. Results: The LBP and non-LBP groups comprised 59 and 117 players, respectively. GIRLoss in the dominant shoulder was a significant independent factor (odds ratio: 1.06, 95% CI: 1.02-1.09; P<0.01) in Model 3, which included hip IR restriction in the non-dominant leg (odds ratio: 0.90, 95% CI: 0.86-0.94; P<0.01).In all models, the explanatory variables fitted were significantly associated with LBP, indicating that the models were significant and fitted well: the AICs (and BICs) for Models 1, 2, and 3 were 198.4 (207.6), 178.6 (187.9), and 168.8 (181.1), respectively, indicating that Model 3 was the best fit. In elite male high school soft tennis players, IR restriction in the dominant shoulder was associated with LBP. IR restriction in the dominant shoulder and non-dominant hip as a significant factor for LBP may contribute to developing an optimal multiple logistic regression model for LBP.

Trunk and shoulder strength and mobility in young female volleyball and handball athletes

IntroductionVolleyball and handball have typical overhead throwing motion that can generate adaptations in the athlete's kinetic chain predisposing to injuries and pain. Considering the importance of the trunk and shoulder in overhead throwing motion and the particularities of these action in different sports, this study aimed to compare the trunk and shoulder muscle strength and mobility in young female volleyball and handball athletes. DesignCross-sectional study with 70 female volleyball and handball athletes between 13 and 18 years old. MethodsShoulder rotators, trunk extension and flexion with rotation strength was measured with a handheld dynamometer (MicroFET 2, Hoogan Health Industries, West Jordan, UT, USA). Shoulder and trunk range of motion was measured with a digital inclinometer (Acummar – model ACU001). Total range of motion deficit (TROM deficit), glenohumeral internal and external rotation of dominant (DOM) and non-dominant (NDOM) shoulder were also calculated. ResultsHandball athletes presented greater muscle strength of trunk flexors/rotators (DOM: 24.96%, effect size: 0.687; NDOM, 31.83%, effect size: 0.798) and dominant shoulder internal rotators (16.65%, effect size: 0.619). The groups showed no difference for trunk and shoulder range of motion and external rotators strength. A TROM (volleyball: 48%, handball: 35%) and a glenohumeral internal rotation deficit (volleyball: 28%, handball: 29%) was found in both groups. ConclusionsYoung female handball athletes have greater strength of trunk flexors/rotators and dominant shoulder internal rotators compared to volleyball athletes. These differences may be related to the different demands required in the movement of these sports.

Relationship between Upper Limb Functional Assessment and Clinical Tests of Shoulder Mobility and Posture in Individuals Participating in Recreational Strength Training.

The upper limb is crucial for functioning in everyday life, thus comprehensive assessment is crucial for physically active people to monitor the effect of exercise and prevent injuries. The aim of this study was to analyse the relationship between upper limb function, shoulder mobility, and posture in individuals who participate in recreational strength training. Thirty-four subjects who engaged in strength training of the upper limbs were divided into two groups: Group 1 (exercise < 3 years) and Group 2 (exercise ≥ 3 years). Lateral scapular slide tests, head and clavicle posture evaluations, and shoulder mobility and closed kinetic chain tests were performed. Group 1 had a greater flexion deficit in both shoulders than Group 2. There was greater external rotation in the non-dominant shoulder and a greater score of the closed kinetic chain test in Group 2 compared to Group 1. There were no statistically significant differences between groups regarding scapula, clavicle, and head posture. The closed kinetic chain test was correlated with a scapula position and symmetry in shoulder flexion in Group 2. Long-term strength training of the upper limbs can be recommended to improve functional abilities in the closed kinetic chain, increase shoulder mobility, and reduce asymmetry.

The COVID-19 lockdown as a model of detraining in division 1 college softball players

BackgroundThe COVID-19 pandemic interrupted the organized training of softball players, similar to the abrupt cessation of sports participation that can happen after an injury. Thus, the COVID-19 pandemic offers a unique model to study how sudden detraining influences softball players.MethodsWe recruited a sample of convenience of National Collegiate Athletic Association Division 1 softball players. They participated in three data collections: pre-lockdown (Jan 2020, T1), post-lockdown (Sept 2020, T2), and before the 2021 season (Jan 2021, T3). Between T1 and T2, players received an at-home conditioning and throwing program, but compliance was not strictly monitored. Between T2-T3, players resumed formal fall training (team-organized workouts, on-field practice, and within-team scrimmage games). At each time point, we collected bilaterally: 1) shoulder internal rotation (IR) and external rotation (ER) range of motion (ROM); 2) shoulder IR and ER strength; 3) hip IR and ER ROM; and 4) hip abduction and extension strength. We used four independent (2 Sides × 3 Timepoints) MANOVA with repeated measures; we followed up significant MANOVA main effect of time with Sidak posthoc tests for pairwise comparisons between time points.ResultsFifteen players participated in this study. We found a significant MANOVA main effect of time for shoulder and hip ROM (p < 0.01). Between T1-T2, dominant shoulder ER ROM decreased 6.5°, dominant shoulder IR ROM increased 4.3°, and lead hip IR ROM increased 4.4°. Between T2-T3, dominant shoulder ER ROM increased 6.3° and trail hip ER ROM increased 5.9°. We found a significant MANOVA main effect of time for shoulder strength (p = 0.03) but not for hip strength (p = 0.18). Between T2-T3, non-dominant shoulder IR and ER increased 1.8 kg and 1.5 kg, respectively.ConclusionA sudden and prolonged cessation of organized training generated changes in shoulder and hip ROM but affected strength to a lesser extent. The loss of shoulder ER and increased lead hip IR ROM are maladaptive as they are associated with injury in overhead athletes. Resuming team-organized training and scrimmage reversed some (shoulder ER), but not all of these changes. Practitioners should monitor clinical variables regularly and be aware of potential changes due to unexpected and prolonged interruptions in training, such as when players suffer sports-related injuries.

Participants with restricted dominant shoulder internal rotation range of motion demonstrate no side-to-side difference in humeral head translation; and no difference before and after joint mobilization: a pilot study.

[Purpose] To compare humeral head translation (HHT) during shoulder elevation between dominant and non-dominant shoulders in participants with limited dominant shoulder internal rotation range of motion (ROM). To determine if joint mobilization alters HHT, and if relationships exist between the bicipital forearm angle and HHT. [Participants and Methods] Fifteen (9 female) participants (age 25.7 ± 6.8 years) with a minimum 15-degree dominant shoulder internal rotation ROM deficit compared to the opposite shoulder participated. All participants underwent bicipital forearm angle (BFA) measurements and ultrasound imaging to measure acromiohumeral and posterior glenohumeral distances in 3 positions: Resting, 90 degrees of shoulder flexion, and 60 degrees of shoulder abduction with full external rotation. Ultrasound images were used to calculate HHT. Participants' dominant shoulders underwent posterior glide mobilization, followed immediately by repeated ultrasound images and ROM measures. [Results] There was no dominant to non-dominant shoulder, or before and after mobilization HHT differences. No correlations existed between bicipital forearm angles and HHT or ROM gains after mobilization. [Conclusion] Participants with internal rotation ROM loss demonstrated symmetrical HHT. Joint mobilization increased ROM, but HHT was unchanged. No relationships existed between BFA and HHT.

Assessment of shoulder proprioception in patients with chronic mechanical cervical pain: A comparative study.

Chronic mechanical cervical pain (CMCP) is a common disabling problem worldwide, interfering with upper extremities function. However studying the impact of CMCP on shoulder proprioception is still lacking. To investigate the impact of CMCP on shoulder proprioception in young adults compared with normal control (NC) individuals. A comparative study was conducted between two groups; 40 patients with CMCP (mean age 32.28 ± 6.586) and 40 age and sex matched NC (mean age 33.43 ± 9.021). The Biodex isokinetic dynamometer was used to assess shoulder active sense of position at 30∘ external and internal rotations. The absolute angular error was calculated for the dominant and non-dominant shoulders. The absolute angular error was significantly increased only in the CMCP at both rotation angles for both shoulders, showing a remarkable increase on the dominant shoulder and in the external rotation range compared with NC. CMCP can significantly impair shoulder proprioception, particularly on the dominant side and in external rotation range. This could emphasize the careful examination of shoulder proprioception for the early detection of shoulders at risk, to eliminate the possibility of shoulder instability and/or injury in young adults with CMCP.

Effect of Indian clubbell exercises on cricket fast bowlers' shoulder kinematics.

The glenohumeral joint's rotational range of motion (ROM) and muscle strength are essential to execute the cricket bowling action. Performing shoulder rotation exercises may increase the rotator cuff muscle strength and rotational ROM. The aim of this study was to test the effect of a six-week exercise programme on shoulder rotational ROM and muscle strength. Twenty-one healthy male cricket fast bowlers were recruited, ranked and pair-matched on initial shoulder rotator muscle strength and assigned to either a shoulder exercise (SE) group or cricket training (CT) only group. The SE group incorporated Indian clubbell exercises in addition to their cricket training. Bowlers in both groups displayed a large increase on the dominant shoulder's internal rotation (IR) ROM, but only the SE group's bowlers displayed ROM improvements (p<0.001) bilaterally for both internal and external rotation. The CT group's fast bowler's non-dominant shoulder IR ROM significantly decreased (p=0.02) during the six weeks. Between groups, only the SE group's bowler's internal rotator muscle strength improved (p<0.001) bilaterally. The observed kinematic changes were statistically significantly greater at a 5% level for the SE group's bowlers (bilateral internal rotators muscle strength, non-dominant shoulder IR ROM and horizontal adduction ROM). Maintenance of the shoulder's rotational ROM and muscle strength is vital for a fast bowler. Cricket bowlers who perform regular clubbell exercises might increase their shoulder's ROM and internal rotator cuffs' muscle strength, which may aid in stabilising their glenohumeral joint while bowling.

Range of Motion Adaptations During a Simulated Game Exposure in Softball Pitchers.

Hip and shoulder range of motion (ROM) alterations are correlated with increased risk of injury in softball athletes. The purpose of this study was to investigate bilateral shoulder and hip ROM adaptation during a simulated softball double-header exposure. It was hypothesized that shoulder and hip ROM would decrease after simulated game exposure and would not return to baseline following a 30-minute break. Thirty (14.8±1.9 yrs, 162.5±18.3 cm, 71.79±16.03 kg) adolescent softball pitchers participated. Testing included: bilateral hip and shoulder ROM (preSG), simulated game exposure (100 pitches), bilateral hip and shoulder ROM (postSG), 30-minute break, bilateral hip and shoulder ROM (preDH), pitching first inning of a simulated double header (12 pitches), and bilateral hip and shoulder ROM (postDH). Two separate repeated measures multivariate analyses of variance tests determined differences in ROM between time points. Dominant shoulder internal rotation ROM and non-dominant shoulder internal and external rotation ROM significantly decreased from preDG. Stride hip external rotation ROM and drive hip internal and external rotation ROM significantly decreased from preSG to preDH. Key results revealed the break given between games may not be sufficient recovery time for hip ROM. Thus, assessing ROM as workload progresses can be a useful strategy for monitoring a softball pitcher's injury risk.

Throwing Shoulder Adaptations Are Not Related to Shoulder Injury or Pain: A Preliminary Report.

Overhead throwing in baseball and softball athletes induces shoulder adaptations theorized to increase risk of shoulder musculoskeletal injury (MSI) and/or pain due to range of motion (ROM) deficits. Shoulder ROM adaptations are associated with a higher risk for developing shoulder MSI and pain. Prospective cohort study. Level 3. A total of 60 National Collegiate Athletic Association Division I athletes cleared for full athletic participation and free from upper extremity MSI in the last 4 weeks (age, 19.0 ± 1.2 years; weight, 82.1 ± 13.7 kg; height, 178.6 ± 11.2 cm; softball, n = 23; baseball, n = 37). Passive glenohumeral internal rotation (IR), external rotation (ER), and horizontal adduction (HA) ROM were measured with the scapula stabilized and used to categorize participants with/without external rotation gain (ERG), external rotation insufficiency (ERI), glenohumeral internal rotation deficit (GIRD), pathological GIRD, and posterior shoulder tightness (PST) before the competitive season. Groups were then compared to assess the incidence of shoulder MSI prospectively and prevalence of shoulder pain at the initial evaluation. Baseball and softball athletes demonstrated significantly less IR ROM in the dominant shoulder (50.6° ± 9.4°) compared with the nondominant shoulder (59.1° ± 8.6°; P < 0.01) and significantly more ER ROM (dominant, 104.6° ± 12.1°; nondominant, 97.7° ± 12.0°; P < 0.01). Incidence of shoulder MSI was 15% but was not significantly related to any shoulder adaptations. No significant relationship was found between prevalence of pain and any shoulder adaptations in the 27% of athletes with pain. Increased ER and decreased IR ROM adaptations in intercollegiate overhead throwing athletes do not appear to be correlated to risk of shoulder MSI or pain. The findings of this level 3 prospective study provide clinicians working with overhead athletes information regarding shoulder MSI risk and pain. It is recommended that clinicians should not use ROM adaptations exclusively to determine increased risk of shoulder MSI.

Factors Associated with Medial Elbow Torque Measured Using a Wearable Sensor in Junior High School Baseball Pitchers

There are no reports investigating the relationship between shoulder range of motion (ROM) and pitching elbow torque in junior high school pitchers. Therefore, we aimed to evaluate the factors associated with medial elbow torque in this population. Sixty-three junior high school baseball pitchers were recruited for this study. The participants completed a questionnaire and passive ROM measurements of shoulder abduction and horizontal adduction. All pitchers pitched three fastballs at maximum effort while wearing a wireless sensor recording pitching mechanics and elbow valgus torque for each pitch. Age (r = 0.65, p &lt; 0.001), height (r = 0.83, p &lt; 0.001), body weight (r = 0.82, p &lt; 0.001), BMI (r = 0.60, p &lt; 0.001), and ball velocity (r = 0.80, p &lt; 0.001) were significantly positively correlated with elbow valgus torque. Participants were divided into two groups based on elbow valgus torque, &gt;30 (high torque [HT]) and &lt;30 N·m (low torque [LT]). Age, height, body weight, BMI, and ball velocity were significantly higher in the HT group than in the LT group. The difference between dominant and non-dominant shoulder horizontal adduction ROM was 5.3 ± 9.3° and 1.0 ± 6.4° in the HT and LT groups, respectively, which was also significantly different. Ball velocity, age, larger physique, and increased restriction of the dominant shoulder’s horizontal adduction ROM were associated with higher medial elbow torque in junior high school pitchers. This suggests that improving the dominant shoulder’s horizontal adduction ROM contributes to preventing elbow injuries.

Mental Fatigue Impairs Tackling Technique in Amateur Rugby Union Players.

To test the effects of mental fatigue (MF) on tackling technique on the dominant and nondominant shoulders in rugby union. Twenty male amateur rugby union players and a total of 953 tackles were analyzed. A randomized crossover counterbalanced design was used across a non-MF (control) and an MF condition. During each condition, each player performed 24 tackles, divided into 4 sets of 6 tackles (3 tackles on each shoulder). In the MF condition, players performed the Stroop Task between each set of tackles. A video recording of each tackle was used to evaluate each player's technical proficiency. A score of 1 point was awarded if a specific technique was performed correctly, and 0 point was given if not. The total score, measured in arbitrary units (AU) out of 11, represents the player's overall tackling proficiency. Overall, players displayed a significantly lower technical proficiency score in the MF condition compared to control (set 2: control 7.30 [7.04-7.57] AU vs MF 6.91 [6.70-7.12] AU, P = .009, effect size (ES) = 0.30 small and set 3: control 7.34 [7.11-7.57] AU vs MF 6.88 [6.66-7.11] AU, P = .002, ES = 0.37 small). For the nondominant shoulder, players had a significantly lower technical proficiency score during the MF condition at set 2 (control 7.05 [6.68-7.41] AU vs MF 6.69 [6.42-6.96] AU, P = .047, ES = 0.29 small) and set 3 (control 7.14 [6.83-7.45] AU vs MF 6.61 [6.35-6.87] AU, P = .007, ES = 0.49 small). MF can diminish a player's overall tackling proficiency, especially when tackling on the nondominant shoulder. The physiological mechanism for this finding may be impaired executive function and suboptimal functioning of neural signals and pathways, which result in less skillful coordination of movement. To further understand and explain MF-induced physiological changes in tackling, the feasibility of monitoring brain activity (such as electroencephalogram) and neuromuscular function (such as electromyogram) needs to be investigated. The findings from this study may also contribute to the development of more effective tackle training programs for injury prevention and performance.

Gender-Specific Patterns of Muscle Imbalance in Elite Badminton Players: A Comprehensive Exploration.

The high-intensity demands of overhead sports exert significant stress on the bilateral shoulder complex, triggering adaptive kinematics and a distinct strength imbalance between internal and external rotators. The imbalance being referred to in the given statement poses a potential risk for humeral head displacement and puts nearby tendons under tension, heightening the vulnerability to injury. This study aims to assess muscle imbalances in badminton athletes. The first hypothesis (H1) suggests that there are differences in internal and external shoulder rotation movements between dominant and non-dominant segments in badminton players. The second hypothesis (H2) proposes that there are variations in muscle imbalances based on gender among elite badminton players. The objectives are to analyze these differences and explore potential gender-related variations in muscle imbalances. The study seeks to contribute to the understanding of muscle imbalances in badminton athletes and potentially guide training and injury prevention strategies in the sport. Using a cutting-edge Hand-Held Dynamometer (HHD), a cohort of 30 elite badminton players underwent an assessment to uncover any bilateral shoulder rotation strength imbalances during a challenging five second isometric maximum contraction. The participants boasted an average age of 17.4 years and a mean playing experience of 7.23 years. The study revealed a notable difference in the ratio of external and internal strength between the dominant and non-dominant shoulders (p = 0.000). This discrepancy amounted to a striking 27.93% muscle imbalance in external rotation/internal rotation strength ratios, favoring the dominant shoulder. Moreover, gender-specific differences were detected, with male players exhibiting a 24.54% muscle imbalance in favor of the dominant shoulder, while female players showcased a more substantial 31.33% imbalance (p = 0.000). In light of these findings, it became evident that elite badminton players possess considerably stronger dominant shoulders compared with their non-dominant counterparts. Furthermore, the study revealed that male players experience less muscular imbalance than their female counterparts.

Effects of an 11-Week Detraining, Imposed by the COVID-19 Confinement, on Handball Players' Shoulder Rotator Isokinetic Profile, Shoulder Range of Motion, and Ball Release Velocity.

Background and Objectives: The COVID-19 confinement significantly impacted the physical condition of athletes. However, the detraining impacts of this period on the shoulder rotator and range of motion in handball players have not been studied. Thus, the main aim of this study was to investigate the effect of this 11-week detraining period, imposed by the COVID-19 pandemic confinement, on the shoulder rotator isokinetic profile (peak torque, ratio, fatigue index), shoulder rotator and flexion range of motion, and ball release velocity in handball players. Materials and Methods: A total of 16 handball players, with a mean age of 22.38 (5.28) years, participated in this study. The isokinetic strength was assessed using two protocols (three repetitions at an angular velocity of 60°/s and 20 repetitions at an angular velocity of 180°/s). In addition, the range of motion and ball release (at jump and standing shots) were measured. All these measurements were assessed before and after the COVID-19 confinement. Results: The results showed a significant reduction in the peak torque of the external rotation of their dominant and non-dominant shoulders. In addition, confinement significantly increased the fatigue index of external rotation and internal rotation and reduced the range of motion of internal rotation. Additionally, the ball release velocity during standing and jump shots was significantly reduced. Conclusions: These results suggested that strengthening external and internal rotation as well as recovering the internal rotation range of motion may be necessary after a detraining period in order to prevent shoulder injuries.

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.

Isometric shoulder strength: Normative Australian population data and associated factors

Background Age and sex are known predictors of isometric shoulder strength and therefore must be accounted for when noting strength values or administering assessments such as the Constant Score. Given the popularity of the Constant Score, it is important to ensure protocols and values remain clinically relevant and are representative of the intended population. Method Isometric shoulder strength was recorded for 511 participants without shoulder pathology using the ChatillonTM hand-held dynamometer. Data were stratified by age and sex for comparison with published normative strength series. Other demographic variables were evaluated using linear regression models. Results Normative values for shoulder strength were generated. Age ( p = .003, [Formula: see text]) and sex ( p &lt; .001, [Formula: see text]) were significant predictors of shoulder strength. Height ( p = .03, [Formula: see text] was a significant predictor of strength in females and weight was a significant predictor of strength in males ( p &lt; .001, [Formula: see text]). Hand dominance was also significant, with non-dominant shoulder strength associated with higher strength in females ( p &lt; .001, [Formula: see text]) and lower strength in males ( p &lt; .001, [Formula: see text]). Conclusion This study generated normative shoulder strength values for a sample of the Australian population and provided a comparison between other normative scores. Significant demographic predictors in addition to age and sex were identified. Level of Evidence III.

Paper 17: Decreased Glenohumeral External Rotation is associated with Elbow Injury in Adolescent Baseball Pitchers

Objectives: To compare bilateral standard glenohumeral range of motion, humeral torsion &amp; humeral torsion-corrected glenohumeral range of motion within and between healthy adolescent baseball pitchers &amp; adolescent baseball pitchers who have an injury to the throwing elbow. Secondarily, to analyze the relationship between humeral torsion angle and glenohumeral rotational motion in adolescent pitchers. Methods: Baseball pitchers aged 13-17 were prospectively enrolled into either a healthy group, if currently pitching in the community without complaint or injured group, if they presented to clinic for an elbow injury related to pitching. Bilateral standard glenohumeral internal &amp; external rotation was measured in degrees using a bubble goniometer with the scapulothoracic joint manually stabilized. Bilateral humeral torsion angles were measured using an Ultrasound &amp; bubble goniometer and were used to calculate humeral torsion-corrected glenohumeral range of motion. Parametric tests were used to compare values within and between groups for both the dominant and non-dominant extremities with significance defined as p&lt;0.05. Pearson’s correlation was used to evaluate the relationship between humeral torsion and standard glenohumeral motion in each group. Results: Twenty-nine healthy and twenty-five injured pitchers were enrolled with no difference in age or hand dominance between groups. The dominant shoulder of both the healthy (Table 2) and injured (Table 3) groups demonstrated a significant increase in humeral retrotorsion with increased standard glenohumeral external rotation &amp; GIRD. However, no difference in humeral torsion-corrected range of motion was present within groups. Injured pitchers displayed less standard &amp; humeral torsion-corrected external rotation of the dominant shoulder as well as less standard external rotation of the non-dominant shoulder compared to the healthy pitchers (Table 4). No difference in internal rotation measurements or humeral torsion was found between groups. A moderate correlation was found between ipsilateral humeral torsion angle and standard glenohumeral external (r=0.49) &amp; internal rotation (r=-0.58) in the dominant shoulder of healthy pitchers (Figure 1) but no correlation (r&lt; 0.3) was found between these measures in the dominant shoulder of injured pitchers. Conclusions: Both healthy &amp; injured adolescent baseball pitchers displayed dominant shoulder GIRD, external rotation gain &amp; retrotorsion of the humerus. In healthy pitchers, dominant glenohumeral motion was correlated to the humeral torsion angle suggesting that the osseous adaptation of humerus significantly contributed to these findings. However, this correlation was not found in the injured pitchers, suggesting that soft tissue factors played a larger role in the development of GIRD &amp; external rotation gain in this group. Additionally, injured pitchers displayed less standard glenohumeral external rotation of both shoulders and less humeral torsion-corrected external rotation of the dominant shoulder compared to healthy pitchers. This suggests a baseline difference in the soft tissue and/or structure of the pitchers’ shoulders between groups. Glenohumeral internal rotation and humeral retrotorsion were not associated with injury status in our study. Clinically, this study suggests that rehabilitation programs including modalities to improve external rotation may be of benefit for adolescent baseball pitchers with elbow injuries &amp; further research on the structural variations of the adolescent pitching shoulder is needed. [Table: see text][Table: see text][Table: see text]