BACKGROUND:Reverse shoulder arthroplasty (rTSA) is often used to restore functionality in patients with joint arthropathy and dysfunctional rotator cuff. As rTSA changes the biomechanical properties of the shoulder, an altered movement pattern of the arm and scapula is to be expected. Previous studies focused on changes of the scapulohumeral rhythm during functional elevation tasks. To our knowledge, no study exists examining scapular kinematics during rehabilitation exercises in a patient population with rTSA. Therefore, this study aimed to analyze 3-dimensional scapular kinematics during 3 commonly used rehabilitation exercises 12 weeks after rTSA surgery. It was hypothesized that scapular kinematics would be different between the horizontal and the vertical plane. Secondly, differences in scapular kinematics in the vertical plane between the open and closed chain were hypothesized. METHODS:In this cross-sectional study, 48 patients (55 shoulders) aged 69 ± 7.4 years participated. Scapular kinematics in terms of anterior/posterior tilt, external/internal rotation, and upward/downward rotation were registered during 3 rehabilitation exercises. Exercises varied based on the plane (horizontal or vertical) and the modality (closed or open chain). Data were analyzed using statistical parametric mapping (SPM). RESULTS:Post hoc pairwise analysis within SPM (SPM(t)) revealed no significant differences among the exercises regarding posterior tilt. During vertical plane exercises (standing wall slide 120° [WS] and standing reach 120° [REACH]), the scapula was more upwardly rotated for most of the time (14.93%-74.63%, P < .001) than during the exercise in the horizontal plane (seated bench slide). No statistically significant differences were found between the vertical open chain (REACH) and the vertical closed chain exercise (WS). For the internal/external rotation, significant differences were found between the horizontal (seated bench slide) and the vertical plane (WS and REACH) (0%-100%, P < .001), and between the open (REACH) and closed chain (WS) vertical exercises (3.0%-91.5%, P < .001), with more external rotation when performing the movement in the vertical plane, and in the closed chain compared with the horizontal plane and the open chain, respectively. CONCLUSION:Scapular kinematics during rehabilitation exercises after rTSA differ, depending on the plane and modality of the exercise. Insight into the impact of changing the plane (horizontal/vertical), and training in open vs. closed chain, may assist physical therapists in the choice of exercises.

OBJECTIVE:To describe the injury rate and profiles of injuries sustained by recreational padel players, reporting time-loss and identifying player- and padel-related factors associated. DESIGN:Cross-sectional survey-based retrospective study. SETTING:Belgian padel clubs. PARTICIPANTS:Recreational adult padel players. MAIN OUTCOME MEASURES:Players completed a questionnaire on lifestyle factors, sports-playing practices, injuries sustained over the year and time to recovery. Injury profiles by gender and location are described. Univariate and multivariate analyses identified factors associated with an increased likelihood of injury. RESULTS:In total, 457 players (66.1 % men) participated, with a median age of 42 years. Overall, 167 players (36.5 %) [95 %CI 32.3; 41.1] sustained 185 injuries over the previous year with an injury rate of 2.81/1000 h playing. Median time to recovery was 30 days (IQR 15-60). Lower limb injuries were most common (53.5 %). Independent factors associated with injuries were age over 30 years, insomnia, less padel-playing experience, playing position on the right, carrying out a warm-up, using an overgrip and not playing another racket sport. CONCLUSIONS:The incidence and profiles of padel injuries are similar to those observed in other studies. Female gender was not associated with higher injury risk. Other player- and padel-associated factors require further investigation to determine causality.

Background and Objectives: CrossFit is a discipline involving a wide range of overhead movements performed at high intensity and under accumulated fatigue that predispose to a high risk of shoulder complex injuries. This study aimed to compare ultrasonographic findings between symptomatic and asymptomatic shoulders in CrossFit athletes. Materials and Methods: A cross-sectional study was conducted to compare ultrasound parameters between the painful and non-painful shoulders in CrossFit athletes with unilateral subacromial shoulder pain. Assessed variables included subacromial subdeltoid bursa thickness, supraspinatus tendon thickness, the acromiohumeral distance, the coracoacromial ligament distance, the bicipital groove angle, cross-sectional area of the biceps brachii longus head tendon, as well as the serratus anterior and lower trapezius muscle thickness. Results: Twenty male CrossFit athletes (forty shoulders) with an average age of 25.70 ± 4.03 years participated in the study. A statistically significant increase was observed (p < 0.05) in the subacromial subdeltoid bursa thickness in the painful shoulder compared to the asymptomatic side. All other ultrasound parameters did not show statistically significant differences. Conclusions: Only subacromial subdeltoid bursa thickness differed significantly between sides. This isolated finding may not fully explain shoulder pain, which cannot be solely attributed to morphological changes. Further research is needed to determine the relationship between shoulder pain and ultrasound features in CrossFit athletes, as well as the role of ultrasound in predicting structural changes in pain conditions.

Background: Upper extremity physical-performance-tests are gaining interest for screening overhead athletes in view of injury prevention, individual performance, and return to play after injury. However, at present, no reference data are available for these tests in a junior tennis population. In addition, the construct validity of these tests with respect to shoulder strength is still unclear. Hypothesis: Junior tennis players will exhibit differences in test performance based on age, sex, and side. Shoulder strength will be moderately to highly correlated with the seated medicine ball throw (SMBT) and the modified-closed-kinetic-chain-upper-extremity test (M-CKCUEST), but not with shoulder endurance test (SET) and the Y-balance-test-upper-quadrant (YBT-UQ). Study Design: Descriptive study, cross-sectional design. Level of Evidence: Level 3. Methods: Four commonly used physical performance tests (PPTs) (YBT-UQ, M-CKCUEST, SMBT, and SET) were executed by 99 junior tennis players aged 9 to 18 years. In addition, isometric external and internal rotation strength was measured, using a hand-held dynamometer. Descriptive reference values were reported, and correlations between the PPTs and strength values were calculated. Results: A linear regression model with backwards stepwise regression was used to identify possible age, sex, and side differences regarding PPTs and strength. Some, but not all reached statistical significance. Moderate-to-high correlations (Pearson correlation coefficients) were found between the M-CKCUEST, SMBT, and SET and strength measurements, establishing acceptable construct validity with respect to strength. No significant correlation was found between the YBT-UQ and strength. Conclusion: Junior tennis players exhibit differences in test performance based on age, sex, and side. The MCKCUEST, SMBT, and SET may be valuable alternatives for strength testing in the clinical setting. Clinical Relevance: These tests may provide a valuable, user-friendly alternative for strength measurements in junior tennis 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.

Background Daily upper limb activities require multitasking and our division of attention. How we allocate our attention can be studied using dual-task interference (DTi). Given the vital role proprioception plays in movement planning and motor control, it is important to investigate how conscious upper limb proprioception is impacted by DTi through cognitive and motor interference. Purpose To examine how dual-task interference impacts conscious upper limb proprioception during active joint repositioning tasks (AJRT). Methods Forty-two healthy participants, aged between 18 and 35, took part in this cross-sectional study. Participants completed two AJRT during three conditions: baseline (single task), dual-cognitive task (serial subtractions), and dual-motor task (non-dominant hand movements). The proprioceptive error (PE; difference between their estimation and targeted position) was measured using an AJRT of 75% and 90% of maximum internal rotation using the Biodex System IIITM and the Upper Limb Proprioception Reaching Test (PRO-Reach). To determine if PEs differed during dual-task interference, interference change scores from baseline were used with one sample t-tests and analyses of variance. Results The overall mean PE with the Biodex was 4.1° ± 1.9 at baseline. Mean change scores from baseline reflect a mean improvement of 1.5° ± 1.0 (p < .001) during dual-cognitive task and of 1.5° ± 1.2 (p < .001) during dual-motor task. The overall mean PE with the PRO-Reach was 4.4cm ± 1.1 at baseline. Mean change scores from baseline reflect a mean worsening of 1.0cm ± 1.1 (p < .001) during dual-cognitive task and improvement of 0.8cm ± 0.6 (p < .001) during dual-motor task. Analysis of variance with the Biodex PEs revealed an interference effect (p < .001), with the cognitive condition causing greater PEs compared to the motor condition and a criterion position effect (p = .006), where 75% of maximum IR produced larger PEs during both interference conditions. An interference effect (p = .022) with the PRO-Reach PEs was found highlighting a difference between the cognitive and motor conditions, with decreased PEs during the contralateral motor task. Conclusion Interference tasks did impact proprioception. Cognitive interference produced mixed results, whereas improved proprioception was seen during motor interference. Individual task prioritization strategies are possible, where each person may choose their own attention strategy when faced with dual-task interference.

Background: Reverse shoulder arthroplasty (RSA) aims to restore function in patients with rotator cuff failure and joint arthropathy. After surgery, patients are routinely referred to a rehabilitation specialist to regain range of motion, strength, and function. A key element in these programs is active exercises. The exercises are often selected based on assumed muscle activity, investigated by electromyography (EMG). In particular, in this patient population, activation of the deltoid and the scapular muscles is the focus of exercise therapy. Currently, most studies investigating muscle activity levels during exercises are performed on healthy individuals. To our knowledge, no study exists analyzing EMG activity during exercises in a population of shoulder arthroplasty patients. Therefore, the study aimed to analyze activity in the shoulder girdle muscles during 6 commonly used rehabilitation exercises 12 weeks after reverse shoulder arthroplasty surgery. Methods: Forty-four patients (50 shoulders) participated in this cross-sectional study, 12 weeks postoperatively (mean 99.18 +/- 12.8 days), aged 68.9 +/- 7.75 years. Surface EMG activity was measured in 10 shoulder girdle muscles: the 3 trapezius parts, serratus anterior, the 3 deltoid parts, latissimus dorsi, and 2 pectoralis major parts during 6 exercises, 3 in a closed chain, and 3 open chain elevation exercises. Results: Gravity-minimized exercises (horizontal plane) show low activity for almost all muscles. Vertical closed kinetic chain exercises show an increased activity compared to horizontal plane exercises. Open kinetic chain exercises against gravity showed the greatest activity in deltoid and upper trapezius. For the other muscles, no consistency in progression was found. Conclusion: This study offers a progression of exercises for patients after reverse shoulder arthroplasty based on increased muscle activity. Level of evidence: Basic Science Study; Kinesiology (c) 2024 Journal of Shoulder and Elbow Surgery Board of Trustees. All rights are reserved, including those for text and data mining, AI training, and similar technologies.

OBJECTIVE: We aimed to develop a consensus-based rehabilitation guideline specifically designed to reduce apprehension following arthroscopic Bankart repair after traumatic anterior shoulder dislocation. DESIGN: Delphi-based consensus. METHOD: A comprehensive list of interventions for potential inclusion in a postoperative rehabilitation guideline was developed. American and European physiotherapists and orthopedic surgeons were invited to participate in a Delphi panel, engaging in 3 survey rounds. The health professionals were surveyed about their level of agreement on both initially listed and newly suggested interventions. Consensus was established when a "critical-to-include" rating was given in >= 70% of all responses. Ten former patients were consulted to identify the intervention during standard care rehabilitation that had the most impact on reducing postoperative apprehension following ABR. Any interventions not initially listed in the first round were added to the second survey round of the Delphi process. RESULTS: Forty-four health professionals reached consensus on a set of 27 interventions for managing apprehension after arthroscopic Bankart repair. New interventions included gradual exposure to shoulder positions eliciting apprehension, training in anterior stability-provoking positions, and education addressing the impact of psychosocial factors. Former patients identified specific interventions that were effective in reducing postoperative apprehension following ABR. These interventions encompassed medicine ball throws, active-assisted wall slides, and kinetic chain exercises in anterior stability-provoking positions. CONCLUSION: Our Delphi process informed expert recommendations for various interventions aimed at addressing apprehension associated with ABR. The recommendations were the foundation for developing a rehabilitation guideline (REGUIDE). The REGUIDE integrates principles from cognitive-behavioral therapy to improve rehabilitation and mitigate apprehension.

Background Rotator cuff (RC) tendinopathy is the most reported shoulder disorder in the general population with highest prevalence in overhead athletes and adult working-age population. A growing body of evidence support exercise therapy as an effective intervention, but to date there are no prospective randomized controlled trials addressing pain as an intervention variable. Methods A single-site, prospective, pragmatic, assessor-blinded randomized controlled superiority trial. Eighty-four patients aged 18–55 years with chronic (symptom duration over 3 months) RC tendinopathy are randomized 1:1 to receive shoulder exercise during which pain is either allowed or avoided. The intervention period lasts 26 weeks. During that period, participants in both groups are offered 8 individual on-site sessions with an assigned sports physiotherapist. Participants perform home exercises and are provided with a pain and exercise logbook and asked to report completed home-based exercise sessions and reasons for not completing sessions (pain or other reasons). Patients are also asked to report load and the number of sets and repetitions per sets for each exercise session. The logbooks are collected continuously throughout the intervention period. The primary and secondary outcomes are obtained at baseline, 6 weeks, 26 weeks, and 1 year after baseline. The primary outcome is patient-reported pain and disability using the Shoulder PAin and Disability Index (SPADI). Secondary outcomes are patient-reported pain and disability using Disability Arm Shoulder and Hand short-form (Quick DASH), and shoulder pain using Numeric Pain Rating Scale. Objective outcomes are shoulder range of motion, isometric shoulder muscle strength, pain sensitivity, working ability, and structural changes in the supraspinatus tendon and muscle using ultrasound. Discussion The results of this study will contribute knowledge about the treatment strategies for patients with RC tendinopathy and help physiotherapists in clinical decision-making. This is the first randomized controlled trial comparing the effects of allowing pain versus avoiding pain during shoulder exercises in patients with chronic RC tendinopathy. If tolerating pain during and after exercise proves to be effective, it will potentially expand our understanding of “exercising into pain” for this patient group, as there is currently no consensus. Trial registration ClinicalTrials.gov NCT05124769. Registered on August 11, 2021.

BACKGROUND:Individuals with rotator cuff-related shoulder pain (RCRSP) have altered proprioception. The relationship between shoulder pain and proprioception is not well understood. PURPOSE:This study aimed to investigate the relationship between shoulder pain and proprioception. STUDY DESIGN:This was a cross-sectional comparative study. METHODS:Twenty-two participants with RCRSP (mean age 27.6 ± 4.8 years) and 22 matched pain-free participants (23.4 ± 2.5 years) performed two upper limb active joint position sense tests: (1) the Upper Limb Proprioception Reaching Test (PRO-Reach; reaching toward seven targets) in centimeters and (2) Biodex System at 90% of maximum internal rotation in degrees. Participants performed three memorization and three reproduction trials blindfolded. The proprioception error (PE) is the difference between the memorized and estimation trials. Pain levels were captured pre- and post-evaluation (11-point Likert Numerical Pain Rating Scale). Relationships between PE and pain were investigated using independent t-tests and Spearman rank correlations. RESULTS:Overall, 22.7% RCRSP participants indicated an increase in pain following the PRO-Reach (X̅ increase of 1.4 ± 1.5 points), while 59% did so with the Biodex (X̅ increase of 2.3 ± 1.8 points), reflecting a clinically important increase in pain. Weak-to-moderate correlations between pain and PEs were found with the Biodex (r = 0.39-0.53) and weak correlations with the PRO-Reach (r = -0.26 to 0.38). Concerning PEs, no significant differences were found between groups with the Biodex (p = 0.32, effect size d = -0.31 [-0.90 to 0.29]). The RCRSP participants demonstrated lower PEs with the PRO-Reach in elevation compared to pain-free participants (global X̅ = 4.6 ± 1.2 cm vs 5.5 ± 1.5 cm; superior 3.8 ± 2.1 cm vs 5.7 ± 2.9 cm; superior-lateral nondominant targets 4.3 ± 2.2 cm vs 6.1 ± 2.8 cm; p = 0.02-0.05, effect size d = 0.72-0.74 [0.12-1.3]). CONCLUSIONS:Individuals with RCRSP demonstrated better upper limb proprioception in elevation, suggesting a change to interoception (sensory reweighting) in the presence of pain.

Introduction Physical performance tests (PPTs) focus on multijoint evaluations in which the athlete performs an activity that represents some aspects of athletic function. Evaluating the electromyographical (EMG) demands of those PPTs enables clinicians to select appropriate PPTs for their athletes. Material and Methods Thirty asymptomatic overhead athletes participated in this descriptive laboratory study. Four PPTs (Y-Balance Test - Upper Quarter (YBT-UQ), Closed Kinetic Chain Upper Extremity Stability Test (CKCUEST), Upper Limb Rotation Test (ULRT) and Shoulder Endurance Test (SET)) were evaluated using surface EMG on both dominant and non-dominant sides to measure muscle activity of upper (UT), middle (MT), and lower (LT) trapezius, serratus anterior (SA), infraspinatus (IS), and posterior deltoid (PD). Results During YBT-UQ performance on both sides, the supporting hand showed high SA activity levels (range: 51–94%MVIC) during all reach directions while IS was most active when supporting the superolateral reach (range: 92 –129%MVIC). For the reaching hand, SA was most active (range: 46–83%MVIC). During the CKCUEST, all muscles were moderately to highly active, with SA (range: 64 – 87%MVIC) and IS (range: 42 – 85%MVIC) being the most active ones in both moving and supporting hand. Moderate to high activity was recorded for all muscles on both sides during the ULRT. For the SET, muscle activity progressively increased with increasing speed for both dominant and non-dominant performance. Conclusion Our results provide specific EMG based information which allows clinicians to better understand PPT performance, enhancing selection of appropriate PPTs that match their patients' needs to return to sport.

The primary aim was to identify differences in magnitude of interlimb asymmetry in isokinetic variables and upper extremity performance tests at four and six months after GHJS surgery in contact and collision athletes compared to an un-injured group. A secondary aim was to investigate if differences in magnitude of asymmetry existed between four months and six months post-operatively. The third aim was to assess if relationships existed among the performance tests and rotational torque measurements.

Background: Shoulder injuries are associated with proprioceptive deficits. Elastic kinesiology tape (KT) is used for treating musculoskeletal disorders, including shoulder injuries, as it argu-ably improves proprioception.Objective: To synthesize the evidence on the effects of elastic KT on proprioception in healthy and pathological shoulders.Methods: Four databases (PubMed, WoS, CINAHL, SPORTDiscus) were searched for studies that investigated the effects of elastic KT on shoulder proprioception. Outcome measures were active joint position sense (AJPS), passive joint position sense (PJPS), kinesthesia, sense of force (SoF), and sense of velocity (SoV). Risk of bias (RoB) was assessed using the Cochrane Collaboration RoB tool for randomized controlled trials (RCTs), and the ROBINS-1 for non-RCTs, while the certainty of evidence was determined using GRADE. Results: Eight studies (5 RCTs, 3 non-RCTs) were included, yielding 187 shoulders (102 healthy and 85 pathological shoulders). RoB ranged from low (2 studies), moderate (5 studies), to high (1 study). Elastic KT has a mixed effect on AJPS of healthy shoulders (n=79) (low certainty). Elas-tic KT improves AJPS (subacromial pain syndrome and rotator cuff tendinopathy, n=52) and PJPS (chronic hemiparetic shoulders, n=13) among pathological shoulders (very low certainty). Elastic KT has no effect on kinesthesia among individuals with subacromial pain syndrome (n=30) (very low certainty).

Background: Proprioception is our sense of body awareness, including the sub-category of active joint position sense (AJPS). AJPS is fundamental to joint stability and movement coordination. Despite its importance, there remain few confident ways to measure upper limb AJPS in a clinic.Objective: To assess a new AJPS clinical tool, the Upper Limb Proprioception Reaching Test (PRO-Reach; seven targets), for discriminant validity, intra-rater and absolute reliability.Design: Cross-sectional measurement study.Methods: Seventy-five healthy participants took part in a single session with 2 consecutive evaluations (E1 and E2) (within-day reliability). Twenty participants were randomly selected to perform a dominant shoulder fatigue protocol (discriminant validity), whereafter a third evaluation was repeated (E3). The PRO-Reach was analyzed with paired t tests (discriminant validity), intra-class correlation coefficients (ICCs) and minimal detectable change [MDC]) (intra-rater: within-day and between-trial relative and absolute reliability).Results: The PRO-Reach supports moderate (mostly superior targets) to excellent (mostly inferior targets) reli-ability. Between-trial ICCs (T1/T2/T3) varied between 0.72 and 0.90, and within-day (E1/E2) ICCs between 0.45 and 0.72, with associated MDC95 values (3.9-5.0 cm). The overall scores (seven targets) supported the strongest within-day reliability (ICC = 0.77). The inferior targets demonstrated the highest between-trial and within-day reliability (ICCs = 0.90 and 0.72). A fatigue effect was found with the superior and superior-lateral targets (P < .05).Conclusions: The inferior targets and overall scores demonstrate the strongest reliability. The use of the PRO-Reach tool may be suitable for clinical use upon further psychometric testing amongst pathological populations.Level of evidence: Level III cross-sectional study.

Background: The purpose of this study was to reach consensus on the most appropriate terminology and issues related to clinical reasoning, examination, and treatment of the kinetic chain (KC) in people with shoulder pain among an international panel of experts.Methods: A 3-round Delphi study that involved an international panel of experts with extensive clinical, teaching, and research experience in the study topic was conducted. A search equation of terms related to the KC in Web of Science and a manual search were used to find the experts. Participants were asked to rate items across 5 different domains (terminology, clinical reasoning, subjective examination, physical examination, and treatment) using a 5-point Likert-type scale. An Aiken coefficient of validity (V) >0.7 was considered indicative of group consensus.Results: The participation rate was 30.2% (n = 16), whereas the retention rate was high throughout the 3 rounds (100%, 93.8%, and 100%). A total of 15 experts from different fields and countries completed the study. After the 3 rounds, consensus was reached on 102 items: 3 items were included in the "terminology"domain; 17 items, in the "rationale and clinical reasoning"domain; 11 items, in the "subjective examination"domain; 44 items, in the "physical examination"domain; and 27 items, in the "treatment"domain. Terminology was the domain with the highest level of agreement, with 2 items achieving an Aiken V of 0.93, whereas the domains of physical examination and treatment of the KC were the 2 areas with less consensus. Together with the terminology items, 1 item from the treatment domain and 2 items from the rationale and clinical reasoning domain reached the highest level of agreement (V = 0.93 and V = 0.92, respectively).Conclusion: This study defined a list of 102 items across 5 different domains (terminology, rationale and clinical reasoning, subjective examination, physical examination, and treatment) regarding the KC in people with shoulder pain. The term "KC"was preferred and a agreement on a definition of this concept was reached. Dysfunction of a segment in the chain (ie, weak link) was agreed to result in altered performance or injury to distal segments. Experts considered it important to assess and treat the KC in particular in throwing or overhead athletes and agreed that no one-size-fits-all approach exists when implementing shoulder KC exercises within the rehabilitation process. Further research is now required to determine the validity of the identified items.Level of evidence: Consensus Development Study; Delphi Method & COPY; 2023 Journal of Shoulder and Elbow Surgery Board of Trustees. All rights reserved.

To determine whether shoulder external (ER) and internal rotational (IR) exercises at five different shoulder abduction angles affect the acromiohumeral distance (AHD). Twenty recreational overhead athletes were included. AHD was measured using real-time ultrasound for each of the five shoulder conditions as follows: neutral shoulder rotation (active-hold) and during ER and IR exercises (isometric and concentric) at five different shoulder-abduction angles (0 degrees, 30 degrees, 45 degrees, 60 degrees, and 90 degrees of abduction). A two-way ANOVA was used to analyze AHD values. Shoulder abduction angle x exercise interaction for AHD was found (F-16,F-304 = 10.92; p < .001; eta 2 = 0.37). For both isometric and concentric conditions, AHD increased during IR exercises (p < .05) yet decreased during ER exercises (p < .05) when compared with each active-hold positions. Shoulder ER and IR exercises influence the AHD in recreational overhead athletes. A larger AHD was observed during shoulder IR exercises, whereas ER exercises failed to maintain the AHD.

ABSTRACT Purpose The primary aim was to identify and quantify differences in interlimb asymmetry magnitudes across a battery of upper extremity strength and performance tests at 4 and 6 months after glenohumeral joint stabilization surgery shoulder stabilization in contact and collision athletes compared with an un-injured group. A secondary aim was to investigate if identified asymmetry magnitudes changed from 4 to 6 months after glenohumeral joint stabilization surgery. The third aim was to explore associations within the different performance and strength variables. Methods Fifty-six male contact and collision sport athletes who had had undergone unilateral glenohumeral joint stabilization were tested at 4 and 6 months after surgery. An un-injured control group (n = 39 for upper extremity performance tests, n = 47 for isokinetic dynamometry) were tested on a single occasion. Three upper extremity force platform-based performance tests and angle-specific concentric internal and external isokinetic shoulder rotational strength were assessed, and interlimb asymmetries were compared between the two groups. Results At 4 months after surgery, the glenohumeral joint stabilization group demonstrated significantly higher absolute interlimb asymmetry values than the un-injured group for almost all the performance test variables. In the ballistic upper-body performance tests, the glenohumeral joint stabilization group achieved only half the body elevation reached by the un-injured (counter-movement push-up jump height (η2 = 0.50) and press-jump jump height (η2 = 0.39)). At 6 months after surgery, absolute interlimb asymmetries reduced for the performance test variables, but some asymmetry persisted. The glenohumeral joint stabilization group had significantly greater absolute interlimb asymmetries for five out the eight isokinetic variables. Conclusions Contact and collision athletes who may be cleared to return to sport at 4 to 6 months after glenohumeral joint stabilization surgery shoulder stabilization continue to demonstrate upper limb strength and performance deficits when compared with their un-injured limb and their un-injured counterparts.

Objectives: To investigate if there is a difference in muscle activity for overhead athletes before and after an intervention with correction of both core and scapula compared to no intervention and is there a difference between overhead athletes with or without shoulder pain. Design: Controlled laboratory EMG study including intervention. Setting: University EMG laboratory. Participants: Sixty overhead athletes, 30 with shoulder pain and 30 healthy controls were included performing plyometric rotational shoulder exercise. Main outcomes: Half of the participants received an intervention the other half were controls with no intervention. EMG muscle activity from 10 scapular, thoraco-humeral and trunk muscles were measured. Results: There were no significant differences in muscle activation levels between the groups with or without intervention. For the shoulder pain group, there were significant lower activity in Upper Trapezius when repeating the exercise. The shoulder pain group had significant higher activity in Pec-toralis Major compared to the Healthy Control group. Conclusions: Most differences were found between the pre-and post-test. Repetition of the exercise seems to be more important than verbal and tactile instructions. Comparing the shoulder pain group with the healthy controls confirms previous findings that, pain patients recruit muscles differently from healthy persons. (c) 2022 Elsevier Ltd. All rights reserved.