Shoulder Muscle Strength Research Articles

Correction: Isometric versus isotonic exercise in individuals with rotator cuff tendinopathy-Effects on shoulder pain, functioning, muscle strength, and electromyographic activity: A protocol for randomized clinical trial.

[This corrects the article DOI: 10.1371/journal.pone.0293457.].

Faster strength recovery and better strength ratio with arthroscopic Latarjet compared to the open technique: An observational study

IntroductionThe arthroscopic bone block has shown reliability and reproducibility regarding functional scores and shoulder mobility compared to the open bone block technique. The recovery of muscle strength, especially the strength ratio external rotator/internal rotator (ER/IR), is crucial to recovering satisfactory function. This ratio should be as near to 1 as possible, meaning a good strength balance. Little is known about the difference in strength recovery between the open and arthroscopic techniques. HypothesisArthroscopic Latarjet reduces surgical stress and improves the strength recovery and strength ratio. ObjectivesTo compare arthroscopic and open Latarjet procedures for shoulder muscle strength and functional outcomes. Material and methodsIt was an observational longitudinal and prospective cohort follow-up. Two groups of patients were accessible for comparison: 35 in an arthroscopy group and 38 in an open group. The main outcome was the muscle strength of shoulder muscles measured with a dynamometer and expressed in Newton (N) at day 21 (D21), D45, D90, D180, and D365 in the operated and contralateral shoulders. The measurements were made for the pectoralis major, the three deltoid fascicles, and the subscapularis. The shoulder ER/IR strength ratio was calculated. Other variables were the range of motion (ROM), the Walch-Duplay (WD), the Western Ontario Shoulder Instability score (WOSI), and the Visual Analogic Scale for pain assessment. The strength, ROM, and functional scores were compared between open and arthroscopy with linear mixed models. ResultsThe median strengths at 52 weeks were significantly higher than at 3 weeks (P<10−4): anterior deltoid (AD) 8N (Q1:7, Q3: 9) versus 4N (Q1:2, Q3: 5), lateral deltoid (LD) 9N (Q1:9, Q3: 11) versus 6N (Q1:4, Q3: 7), posterior deltoid (PD) 14N (Q1:12, Q3: 15) versus 9N (Q1:8, Q3: 10), subscapularis 10N (Q1:9, Q3: 12) versus 7N (Q1:5, Q3: 8), and pectoralis major (PM) 11N (Q1:9, Q3: 12) versus 7N (Q1:5, Q3: 10). The overall strengths were lower in the open group compared to the arthroscopy group: AD −2.1N (CI95%[−3.1−−1.2], p=0.0005), LD −1.3N (CI95% [−2.4−−0.15], p=0.03), PD −0.35N (CI95% [−1–0.9], p=0.52), subscapularis −2.1N (CI95% [−3.3−−0.7], p=0.006), and PM −1.4N (CI95% [−2.2−−0.02], p=0.03). The ER/IR ratio was stable throughout the follow-up for both the operated and contralateral shoulders (p>0.5). The overall mean ratio was 1.3 (median 1.2, Q1: 1, Q3:1.45) for the operated shoulder and 1.1 (median 1, Q1: 0.9, Q3:1.3) for the contralateral shoulder (p=0.0004). The average ER/IR ratio was 0.27 points higher in the open group (CI95% [0.1–0.46], p=0.003). The ROM was similar between the two groups, and there was no correlation between the ER/IR ratio and the ROM (p>0.5). The VAS < 3 weeks and WD > 12 weeks were significantly poorer in the open group: +0.61 (CI95% [0.03–1.16] p=0.02), and −7.3 points (CI95% [−13−−0.01], p=0.05), on average, respectively. ConclusionThe patients in the arthroscopy group had a better ER/IR strength ratio (closer to 1) and better WOSI after 12 weeks. The strength and the ROM were not correlated with each other. Level of evidenceIII.

Rehabilitation strategies and magnetic resonance imaging techniques for shoulder injuries in sports

ObjectiveShoulder sleeve injuries are high-risk in men's tennis, with rehabilitation focusing on activating shoulder muscle groups to regain strength. Specific plans use electromyography and isokinetic instruments to compare muscle activity and torque pre- and post-rehabilitation. The goal is to explore training effects on rotator cuff injuries and assess routine MRI and MRI shoulder arthrography for diagnostic value in shoulder injuries. This aims to provide a reference for restoring shoulder function in male tennis players. MethodsTwenty college students (n = 20) with rotator cuff injuries from a university tennis program were selected as experimental subjects, matched based on gender and injury severity, and divided into experimental (n = 10) and control (n = 10) groups. A paired sample T-test assessed the impact of rehabilitation training on muscle recruitment and strength around the shoulder joint in the experimental group before and after training. This evaluated the influence of rehabilitation plans on shoulder muscle mobilization and strength. Another paired sample T-test compared indicators before and after the experiment, examining mechanisms underlying the effects of functional rehabilitation training on shoulder sleeve injuries in male tennis players. Results(1) Surface electromyography (EMG) results for internal/external rotation showed a significant increase in anterior, middle, and posterior deltoid EMG values (P < 0.05). Supraspinatus and infraspinatus muscles exhibited substantial increases (P < 0.01), while no significant change occurred in the teres minor muscle. (2) Adduction/abduction EMG tests at 60°/s, 90°/s, and 120°/s revealed significant increases (P < 0.01) in deltoid bundles and supraspinatus/infraspinatus muscles for both experimental and control groups. Teres minor muscle showed no significant change. (3) Isokinetic muscle strength tests indicated a significant peak torque increase (P < 0.01) during inward/outward rotation at 60°/s, 90°/s, and 120°/s for the experimental group compared to the control group. ConclusionA 10-week functional shoulder rehabilitation training program can enhance the strength, endurance, and neuromuscular recruitment of shoulder-related muscles in male tennis players with rotator cuff injuries. This approach, combined with the diagnostic capabilities of routine MRI and MRI shoulder arthrography, enables modifications in the body's ongoing adaptation to injuries. This, in turn, contributes to improved shoulder joint stability and effectively facilitates the functional recovery of the rotator cuff muscle group.

Effect of Core Stability Exercises on Shoulder Pain, Muscle Strength, and Range of Motion in Female Swimmers With Shoulder Impingement Syndrome

Background and Aims Previous studies have shown that core stability exercises reduce the applied force on the upper limbs in swimmers. However, the effect of these exercises on the range of motion (ROM), muscle strength, and pain in the shoulder of swimmers is unclear. Therefore, this study aims to investigate the effect of a core stability exercise program on shoulder pain, muscle strength, and ROM in female swimmers with shoulder impingement syndrome (SIS). Methods The study population consists of all female swimmers with SIS in Tabriz, Iran. Twenty eligible swimmers were selected and randomly divided into two exercise (n=10) and control (n=10) groups. The shoulder pain, ROM, and muscle strength were measured by the shoulder pain and disability index, a goniometer, and the bench press (One repetition maximum), respectively. The exercise group participated in a specific core stability exercise program. The data were analyzed in SPSS software, version 24 using repeated measures analysis of variance, independent t-test, and paired t-test for within-group and between-group comparisons. The significance level was set a t 0.05. Results After exercise, the amount of shoulder pain in the experimental group was significantly reduced compared to the control group (P=0.0001). It also had a significant effect on the ROM of the shoulder in this group. In addition, there was a significant difference in shoulder muscle strength in the experimental group before and after exercise (P=0.0001), but this difference was not significant in the control group (P=0.138). Moreover, there was a significant interaction effect of time and group in the shoulder girdle muscle strength (P=0.001). Conclusion The core stability exercises can reduce shoulder pain and improve shoulder ROM and muscle strength in female swimmers with SIS. Performing core stability exercises is recommended to reduce pain and improve shoulder girdle function in these swimmers.

Investigation of Neck and Shoulder Muscle Strength by Scapula-Spinous Distance Difference in Individuals with Shoulder Impingement Syndrome

Omuz sıkışma sendromu stabilite ve mobilitede etkili olan yapıların subakromial arkta sıkışması ile oluşan kompleks bir durumdur. Bu duruma çeşitli faktörler sebep olmaktadır. Skapular diskinezi omuz sıkışma sendromu olan hastalarda sıklıkla görülen bir bulgu olup kas kuvvet dengesizliği ile ilişkilidir. Bu çalışmanın amacı omuz sıkışma sendromu olan bireylerde skapula-spinöz mesafe ile boyun ve omuz kas kuvveti arasındaki ilişkinin incelenmesi ve sağlıklı kontrol grubuyla karşılaştırılmasıdır. Araştırmaya omuz sıkışma sendromu tanısı alan (deney grubu) 12 hasta ile 8 sağlıklı (kontrol grubu) birey olmak üzere toplam 23 kişi dahil edildi. Araştırmada skapular diskinezi değerlendirmesi için ‘Lateral Skapula Testi’, kas kuvveti ölçümü için el dinamometresi ile kas kuvvet testi, ağrı ve disabilite durumunu değerlendirmek için ‘Omuz Ağrı ve Özürlülük (SPADI)’ ölçeği kullanıldı. İstatiksel analiz için Shapiro-Wilks testi, bağımsız örneklemler t-testi ve Mann-Whitney U testi kullanıldı. Deney ve kontrol grubunun skapular asimetri bakımından benzer oldukları belirlendi (p&gt;0,05). Deney grubunda etkilenmiş taraf omuz fleksör, ekstansör, horizontal abdüktör, horizontal addüktör, internal rotatör ve eksternal rotatör kas kuvvetinin kontrol grubuna göre daha zayıf olduğu belirlendi (p

Prediction model of subacromial pain syndrome in assembly workers using shoulder range of motion and muscle strength based on support vector machine

Subacromial pain syndrome (SAPS) is the most common upper-extremity musculoskeletal problem among workers. In this study, a machine learning model was built to predict and classify the presence or absence of SAPS in assembly workers with shoulder joint range of motion (ROM) and muscle strength data using support vector machine (SVM). Permutation importance was used to determine important variables for predicting workers with or without SAPS. The accuracy of the support vector classifier (SVC) polynomial model for classifying workers with SAPS was 82.4%. The important variables in model construction were internal rotation and abduction of shoulder ROM and internal rotation of shoulder muscle strength. It is possible to accurately perform SAPS classification of workers with relatively easy-to-obtain shoulder ROM and muscle strength data using this model. In addition, preventing SAPS in workers is possible by adjusting the factors affecting model building using exercise or rehabilitation programs. Practitioner summary: This study aimed to create a machine learning model that can predict and classify SAPS using shoulder ROM and muscle strength and identify the variables that are of high importance in model construction. This model could be used to predict or classify workers’ SAPS and manage or prevent SAPS.

Shoulder and scapulothoracic impairments in women with breast cancer-related lymphedema in the upper limb: A cross-sectional study shoulder and breast cancer-related lymphedema

IntroductionLymphedema in the upper limb as a complication of breast cancer may lead to shoulder pain and dysfunctions. Objective: To compare the scapular positioning, the shoulder range of motion, and muscle strength among women undergoing treatment for breast cancer with and without lymphedema and a control group. MethodsThis cross-sectional study evaluated women undergoing treatment for breast cancer (N = 25) and without lymphedema (N = 25), and a control group (N = 25). Static scapular positions and shoulder range of motion were measured by using an inclinometer. The shoulder and periscapular muscle strength were measured by using a hand-held dynamometer and the Disabilities of the Arm, Shoulder, and Hand Questionnaire was applied. Linear regression of the mixed effects model was used to compare the groups. ResultsBoth groups of mastectomized women had reduced shoulder range of motion, scapular upward rotation, and muscle strength for shoulder and periscapular muscles compared to the control group. Also, women undergoing treatment for breast cancer with lymphedema had reduced shoulder range of motion, scapular upward rotation, increased anterior tilt, reduced muscle strength of the upper trapezius, and greater upper limb disability compared to women without lymphedema. ConclusionWomen undergoing treatment for breast cancer with lymphedema had even greater shoulder and scapulothoracic impairments when compared to the control group and women without lymphedema.

Scapular stabilization exercise training improves treatment effectiveness on shoulder pain, scapular dyskinesis, muscle strength, and function in patients with subacromial pain syndrome: A randomized controlled trial

IntroductionSubacromial pain syndrome (SPS) is a common cause of shoulder pain, and is associated with functional limitation, workdays lost, disability, and poor quality of life. PurposeOur purpose was to investigate the effects of scapular stabilization exercises in patients with SPS. MethodSixty-four patients with SPS who also exhibit observable scapular dyskinesis defined by the scapular dyskinesis test were recruited and randomized to scapular stabilization exercise training group or to control group. All participants received the same rehabilitation protocol including glenohumeral and scapular mobilization, pendulum exercises, shoulder stretching, range of motion exercises, strengthening, and proprioceptive exercises. Patients in the scapular stabilization exercise training group performed additional scapular stabilization exercises. The presence of scapular dyskinesis, shoulder pain severity, motion, muscle strength, scapular upward rotation, and shoulder disability were assessed before and after the four-week rehabilitation program. ResultsThe scapular stabilization exercise training group had better improvement in scapular dyskinesis, pain, muscle strength, and shoulder disability compared to the control group (p < 0.05). However, there was no statistically significant time-group interaction regarding shoulder motion and scapular upward rotation (p > 0.05). ConclusionsScapular stabilization exercises added to the shoulder mobilization, stretching, and strengthening are effective in improving scapular dyskinesis, reducing pain, increasing muscle strength and shoulder function in patients with SPS accompanied by scapular dyskinesis.

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.

Mediating the Connection: The Role of Pain in the Relationship between Shoulder Muscle Strength, Joint Position Sense, and Sub-Acromial Impingement Syndrome

Sub-acromial Impingement Syndrome (SIS) is a prevalent shoulder pathology characterized by pain, muscle weakness, and altered joint position sense (JPS). This prospective study aimed to comprehensively assess the relationship between shoulder muscle strength, JPS, and pain in individuals with SIS. A total of 100 participants, including 50 with SIS and 50 healthy controls, underwent shoulder muscle strength testing and JPS evaluation in various directions (flexion, abduction, medial rotation, and lateral rotation). Pain intensity was quantified using a visual analog scale. Correlation analyses were conducted to explore the associations between muscle strength, JPS, and pain, with Cohen’s d values indicating the effect size. Individuals with SIS exhibited significantly lower shoulder muscle strength and greater JPS errors compared to the healthy controls (p &lt; 0.001, Cohen’s d = 0.51 to 0.84). The results showed strong positive correlations between muscle strength and JPS in all assessed directions (p &lt; 0.001, with r values ranging from 0.35 to 0.62). Mediation analysis revealed that pain partially mediated the relationship between muscle strength and JPS in all directions (p &lt; 0.005). This study highlights the multifaceted nature of SIS, emphasizing the coexistence of muscle weakness, proprioceptive impairments, and pain. The findings underscore the importance of addressing these factors in the comprehensive rehabilitation of individuals with SIS to optimize functional outcomes and enhance their quality of life.

Effectiveness of Pulse Electromagnetic Field Therapy in Patients With Subacromial Impingement Syndrome: A Double-Blind Randomized Sham Controlled Study

ObjectivesTo evaluate the 3-month effects of pulsed electromagnetic field therapy (PEMF) in the treatment of subacromial impingement syndrome (SIS). DesignPlanned analysis of a randomized controlled trial with 4- and 12-week follow-ups. SettingPhysical medicine and rehabilitation clinic, treatment unit. ParticipantsOf the 250 individuals screened for eligibility, participants with a diagnosis of SIS (N=80) were randomized to intervention or control groups. InterventionThe first group received PEMF + exercise and the second group received sham PEMF + exercise 5 days a week for a total of 20 sessions. Main Outcome MeasuresVisual Analog Scale (VAS), Constant Murley Score (CMS), Shoulder Pain and Disability Index (SPADI), Short Form-36 (SF-36) Quality of Life Questionnaire, and shoulder muscle strength measurement with an isokinetic dynamometer. Evaluations were performed before treatment (T0), after treatment (T1), and 12th week (T2). ResultsEvaluation at T1 and T2 showed improvement in most parameters in both groups compared with baseline. In the comparison between the 2 groups at T1 and T2, more improvement was found in the PEMF group in most parameters. ConclusionsIn our study, PEMF was found to be superior to sham PEMF in terms of pain, ROM, functionality, and quality of life at the first and third months.

Test-retest reliability of isometric shoulder muscle strength during abduction and rotation tasks measured using the Biodex dynamometer.

The Constant score (CS) is often used clinically to assess shoulder function and includes a muscle strength assessment only for abduction. The aim of this study was to evaluate the test-retest reliability of isometric shoulder muscle strength during various positions of abduction and rotation with the Biodex dynamometer and to determine their correlation with the strength assessment of the CS. Ten young healthy subjects participated in this study. Isometric shoulder muscle strength was measured during 3 repetitions for abduction at 10° and 30° abduction in the scapular plane (with extended elbow and hand in neutral position) and for internal and external rotation (with the arm at 15° abduction in the scapular plane and elbow flexed at 90°). Muscle strength tests with the Biodex dynamometer were measured in 2 different sessions. The CS was acquired only in the first session. Intraclass correlation coefficients (ICCs) with 95% confidence interval, limits of agreement, and paired t tests for repeated tests of each abduction and rotation task were calculated. Pearson's correlation between the strength parameter of the CS and isometric muscle strength was investigated. Muscle strength did not differ between tests (P>.05) with good to very good reliabilities for abduction at 10° and 30°, external rotation and internal rotation (ICC >0.7 for all). A moderate correlation of the strength parameter of the CS with all isometric shoulder strength parameters was observed (r>0.5 for all). Shoulder muscle strength for abduction and rotation measured with the Biodex dynamometer are reproducible and correlate with the strength assessment of the CS. Therefore, these isometric muscle strength tests can be further employed to investigate the effect of different shoulder joint pathology on muscle strength. These measurements consider a more comprehensive functionality of the rotator cuff than the single strength evaluation in abduction within the CS as both abduction and rotation are assessed. Potentially, this would allow for a more precise differentiation between the various outcomes of rotator cuff tears.

Evaluation of muscle strength recovery following superior capsular reconstruction using a tensor fascia lata graft: A comparison with the unaffected side.

Superior capsular reconstruction (SCR) using a tensor fascia lata graft has been performed in patients with irreparable rotator cuff tears and shoulder pseudoparalysis (PPS), and good clinical results have been reported. This procedure can be indicated for younger patients who are highly active in sports and manual labor from the viewpoint of joint preservation. However, this procedure supplements the defect with a graft that has no muscle contractility; therefore, the extent to which shoulder muscle strength is recovered after SCR remains unclear. We hypothesized that the recovery of muscle strength after SCR would not be normalized and would be only approximately 50% of that of the healthy (unaffected) side. This study aimed to evaluate muscle strength after SCR in patients with PPS due to irreparable rotator cuff tears and the extent of recovery by comparing with that of the unaffected side. In total, 20 patients who underwent SCR for PPS using a tensor fascia lata graft with a minimum 2-year follow-up were included. Shoulder muscle strength in abduction, internal rotation, and external rotation was evaluated using a handheld dynamometer. Muscle strength was compared to that on the unaffected side, and the affected/unaffected ratio was measured. Shoulder range of motion (ROM) and acromiohumeral distance (AHD) were also evaluated. The postoperative ROMs and AHD (4.0 ± 1.4 mm vs. 8.4 ± 1.9 mm, P < .001) were significantly improved compared to those preoperatively. In external and internal rotation, the muscle strength of the affected side was recovered by approximately 80% compared to that of the unaffected side. However, in abduction, the muscle strength of the affected side (2.9 ± 1.5 kg) could not reach 50% (48.0 ± 15.9%, range: 25.0-76.5%) of that of the unaffected side (5.9 ± 1.8 kg). Abduction strength was not sufficiently restored after SCR when compared to that on the unaffected side.

Shoulder structures and strength in competitive preadolescent swimmers: A longitudinal ultrasonographic study.

Repetitive shoulder movements during competitive training may cause changes in the strength of periarticular shoulder structures in preadolescent swimmers. To prospectively determine the effects of training on shoulder periarticular structures and muscle strength in preadolescent swimmers. Prospective cohort study. Community-based natatorium. Twenty-four preadolescent swimmers aged 10-12 years. Not applicable. Measurements were repeated in three periods as preseason, midseason, and postseason. Ultrasonographic measurements (supraspinatus tendon thickness, humeral head cartilage thickness, deltoid muscle thickness, and acromiohumeral distance) were performed using a portable device and a linear probe. Shoulder (flexion, extension, abduction, internal and external rotation) and back (serratus anterior, lower, and middle trapezius) isometric muscle strength were measured with a handheld dynamometer. Supraspinatus tendon thickness and acromiohumeral distance were similar in all periods (all p > .05); however, deltoid muscle and humeral head cartilage thicknesses increased throughout the season (p = .002, p = .008, respectively). Likewise, whereas shoulder muscle strength increased (all p < .05), back muscle strength was similar in all periods (all p > .05). In preadolescent swimmers, acromiohumeral distance and supraspinatus tendon thickness seem to not change; but humeral head cartilage and deltoid muscle thicknesses as well as shoulder muscle strength increase throughout the season.

The Effect of 8-week Online Scapular-focused Training on Scapular Kinematics, Proprioception, and Selected Muscles Strength in Female Volleyball Players With Glenohumeral Internal Rotation Deficit

Purpose: One of the most significant risk factors for throwing athletes is an internal rotation deficit of the shoulder joint. This study aims to investigate 8-week online scapular-focused training on the scapular kinematics, proprioception, and strength of particular shoulder muscles in female volleyball players with glenohumeral internal rotation deficit. Methods: The present study was conducted using a two-group with pre and post-test design. Based on the inclusion and exclusion criteria, 30 female athletes with abnormalities in the shoulder joint’s internal rotation were split into two groups, experimental (n=15) and control (n=15). In the pre-test, goniometers were used to measure shoulder range of motion, isokinetic devices were used to measure proprioception and rotator cuff muscle strength, and inclinometers were used to measure scapular kinematics. The experimental group’s participants underwent 8-week online scapular-focused training, lasting 30 minutes over three sessions each week. These exercises encompassed strength (with TheraBand) and stretching activities. Ultimately, intra-group and inter-group differences were examined using SPSS software, version 20 using paired t-tests and analysis of covariance (ANCOVA) at a significance level of 0.95. Results: The results of paired t-test revealed that only the experimental group and the pre-test and post-test had a significant difference in all study variables (P&lt;0.05). Additionally, the results of the analysis of covariance (ANCOVA) demonstrated a significant difference between the two groups’ shoulder proprioception at 45° and 90° in the post-test (P=0.001 and P=0.01, respectively). The two groups also differed significantly in the scapular kinematics at all angles of 45°, 90°, and 135° as well as at the limit of the shoulder’s range of motion (P=0.01, P=0.04, P=0.001, and P=0.001, respectively). Additionally, significant differences were observed between the two groups in all variables of isokinetic strength of concentric internal rotation, isokinetic strength of concentric external rotation, isokinetic strength of eccentric internal rotation, and isokinetic strength of eccentric external rotation (P=0.001, P=0.02, and P=0.001, respectively). Conclusion: Based on the results, it can be concluded that 8-week online scapular-focused training improves scapular kinematics, proprioception, and shoulder internal and external rotator muscle strength in female volleyball players experiencing internal rotation deficiencies of the shoulder joint. It is advised that coaches, experts, and occupational therapists employ these workouts to enhance the aforementioned factors in female volleyball players experiencing shoulder internal rotation deficiencies.

Unilateral seated shot-put test, muscle strength, and range of motion on recreational athletes with chronic shoulder pain: Cross-sectional study

ObjectiveTo correlate the functional performance assessed by means of the Unilateral Seated Shot-Put Test (SSPT) with shoulder muscle strength, range of motion (ROM), and handgrip strength in recreational athletes with chronic shoulder pain. Methods and materialsThe sample was composed of recreational athletes with nonspecific pain in the dominant shoulder ≥3 months, both sexes, aged between 18 and 45 years. We diagnosed shoulder pain by reporting pain intensity ≥3 points on the Numerical Rating Pain Scale and used the Shoulder Pain and Disability Index, Pain-Related Catastrophizing Thoughts Scale, and Baecke Questionnaire. Moreover, shoulder muscle strength, handgrip strength, ROM, and functional performance using the SSPT were evaluated. We used the Spearman correlation coefficient to investigate the correlation between the variables. ResultsNineteen participants were included. Most of the sample consisted of adult women with adequate body mass and pain predominantly in the right shoulder. We observed higher correlation magnitudes of the SSPT with handgrip strength (rho = 0.818 to 0.833, p < 0.05). Correlations of the SPPT with shoulder musculature strength were of low to moderate magnitude (rho = 0.461 to 0.672, p < 0.05). The only significant correlation (p < 0.05) found was between the SSPT and ROM (horizontal adduction), however, with a weak magnitude (rho <0.50). ConclusionSSPT correlates strongly with handgrip strength and moderately with shoulder muscle strength in recreational athletes with chronic shoulder pain.

The Change in Shoulder Muscle Strength After Superior Capsule Reconstruction for Reinforcement of Arthroscopic Rotator Cuff Repair

The Change in Shoulder Muscle Strength After Superior Capsule Reconstruction for Reinforcement of Arthroscopic Rotator Cuff Repair

The clinical impact of retears after repair of posterosuperior rotator cuff tears: a systematic review and meta-analysis.

Structural integrity after rotator cuff repair is frequently not achieved, but the clinical consequences of a retear remain disputed. The purpose of this meta-analysis was to analyze the relationships between postoperative cuff integrity and shoulder pain and function. We searched the literature for studies of surgical repair of full-thickness rotator cuff tears published after 1999 describing rates of retear and clinical outcomes and providing sufficient data to estimate effect sizes (standardized mean differences [SMDs]). Baseline and follow-up data of healed and failed repairs were extracted, including shoulder-specific scores, pain, muscle strength, and health-related quality of life. Pooled SMDs, mean differences, and overall change from baseline to follow-up according to structuralintegrity at follow-up were calculated. Subgroup analysis was performed to assess the influence of study quality on differences. This analysis included 43 study arms with 3350 participants. The average age of the participants was 62 years (range, 52-78 years). The median number of participants per study was 65 (interquartile range, 39-108). At a median of 18 months' follow-up (interquartile range, 12-36 months), 844 repairs (25%) were described as retorn on imaging. The pooled SMD between healed repairs and retears at follow-up was 0.49 (95% confidence interval [CI], 0.37 to 0.61) for the Constant-Murley score, 0.49 (95% CI, 0.22 to 0.75) for the American Shoulder and Elbow Surgeons score, 0.55 (95% CI, 0.31 to 0.78) for other shoulder-specific outcomes combined, 0.27 (95% CI, 0.07 to 0.48) for pain, 0.68 (95% CI, 0.26 to 1.11) for muscle strength, and -0.001 (95% CI, -0.26 to 0.26) for health-related quality of life. The pooled mean differences were 6.12 (95% CI, 4.65 to 7.59) for the Constant-Murley score, 7.13 (95% CI, 3.57 to 10.70) for the American Shoulder and Elbow Surgeons score, and 0.49 (95% CI, 0.12 to 0.87) for pain, all below the commonly suggested minimal clinically important differences. The differences were not significantly affected by study quality and were generally modest compared with overall improvements from baseline to follow-up for both healed and failed repairs. The negative impact of retears on pain and function was statistically significant but judged to be of minor clinical importance. The results indicate that most patients may expect satisfactory outcomes despite retears.

Do the Testing Posture and the Grip Modality Influence the Shoulder Maximal Voluntary Isometric Contraction?

Assessing and monitoring shoulder strength is extremely important during rehabilitation. A fixed dynamometer represents a valid and inexpensive assessment method. However, it has not been studied whether posture and grip modality influence shoulder muscle strength. The aim of this study was to compare shoulder strength values between sitting and standing positions and between the handle and cuff grip modalities. A total of 40 volunteers were divided into a posture (PG) and a handle-cuff group (HCG). Participants in the PG were asked to perform a maximum voluntary isometric contraction (MVIC) for shoulder flexion, extension, ab-adduction, and intra-extra rotation in standing and sitting positions. The HCG participants were tested in a standing position while holding a handle or with a cuff around their wrist. PG showed higher forces in the standing position for shoulder flexion (p = 0.009); internal rotation showed higher values in the sitting position (p = 0.003). ER/IR ratio was significantly higher in the standing position (p < 0.001). HCG showed higher significant forces during cuff modality in all positions and grip modalities, including the ER/IR ratio (p < 0.05). Different body positions and grip modalities influenced the assessment of shoulder strength as recorded by a fixed dynamometer; therefore, these factors should be carefully considered when carrying out a shoulder strength assessment, and we encourage the development of assessment guidelines to make future clinical trial results comparable.

Shoulder muscle imbalance as a risk factor for shoulder injury in elite badminton players: A prospective study

ObjectivesTo assess the impact of preseason shoulder testing on the risk of significant shoulder injury (SSI) in elite badminton players. DesignProspective cohort study. SettingSecondary care, academic medical center. ParticipantsNineteen elite badminton players (19.37 ± 4.79 years, n = 13 males). Main outcome measuresAt preseason, they had shoulder examination tests including the table-to-acromion distance and the glenohumeral rotation range of motion. The glenohumeral internal rotation deficit (GIRD) was calculated. Isokinetic internal and external rotator shoulder muscle strength was tested at 60°/s (concentric and eccentric modes) and 240°/s (concentric mode). Bilateral strength ratio (non-dominant:dominant) and unilateral agonist:antagonist conventional and functional ratios (FR: eccentric-to-concentric) were calculated. ResultsDuring the follow-up time of 38 weeks, SSIs were assessed by an experienced sport physician and 42% of the participants sustained at least one SSI at their dominant side. The preseason GIRD and FR at 240°/s (FR240) were independently associated with SSIs (G2 = 6.28, p = .012 and G2 = 6.23, p = .013, respectively). FR240 < 0.69 (odds ratio = 28.0) and GIRD> 14° (odds ratio = 36.14) were predictors for SSIs. ConclusionsLower functional deceleration ratio and greater GIRD are associated with a higher risk of SSI at the dominant side in elite badminton players.