Shoulder External Rotation Strength Research Articles

Effects of Eccentric Versus Concentric Strengthening in Patients With Subacromial Pain Syndrome: A Randomized Controlled Trial.

Subacromial pain syndrome (SPS) is the most common cause of shoulder pain. Therapeutic exercise is the first-line treatment for SPS; however, the ideal exercise type remains unclear. Here, we compared the effects of eccentric and concentric strengthening in patients with SPS. Adding isolated eccentric strengthening to a multimodal physiotherapy program (MPP) would lead to greater improvements in outcomes compared with either MPP alone or adding isolated concentric strengthening to the MPP. Randomized controlled trial. Level 2. A total of 45 patients were randomized to eccentric strengthening (ESG), concentric strengthening (CSG), and control (CG) groups; all groups received the MPP. The strengthening groups also performed group-specific strengthening. Shoulder pain, abduction and external rotation (ER) strength, joint position sense (JPS), the Constant-Murley Score (CMS), and the Disabilities of the Arm, Shoulder and Hand score were collected at baseline, after 12 weeks of treatment, and at week 24. For CMS, ESG exhibited a greater, but not clinically meaningful, improvement than CSG and CG (P < 0.05). Eccentric abduction strength increased in ESG compared with CG. From baseline to follow-up, abduction strength increased in ESG compared with CSG and CG. Eccentric abduction strength increased in CSG compared with CG. JPS at abduction improved in the ESG compared with CG. Other between-group comparisons were not significant (P > 0.05). In SPS, eccentric strengthening provided added benefits, improving shoulder abduction strength and JPS at abduction, and was superior to concentric strengthening for improving shoulder abduction strength. Neither strengthening approach had an additional effect on shoulder function, pain, ER strength, or rotational JPS. Clinicians could implement eccentric strengthening as a motor control retraining for strength and proprioception gain rather than for pain relief and reducing disability.

Fatty Degeneration of the Rotator Cuff Muscles Improves in Shoulders with Successful Arthroscopic Rotator Cuff Repair: A Prospective Study Using Quantitative T2 Mapping Techniques, with 2-Year Follow-up.

There remain arguments regarding whether fatty degeneration of the rotator cuff muscles improves following rotator cuff repair. The purpose of this study was to prospectively investigate changes in fatty degeneration of the rotator cuff muscles, quantitatively measured on magnetic resonance imaging (MRI) with use of transverse relaxation time (T2) mapping techniques, and to assess the relationship between these changes and clinical outcomes. Patients were included if they were scheduled for arthroscopic rotator cuff repair using the suture-bridge technique between June 2014 and December 2015, underwent preoperative MRI including the T2 mapping sequence, and consented to participate in the study. Exclusion criteria consisted of trauma within 2 months before preoperative MRI, isolated subscapularis tears, patch augmentation, neuromuscular disease, and a follow-up duration of <2 years. MRI scans were acquired preoperatively and at 2 years postoperatively, and T2 values of the supraspinatus and infraspinatus muscles were measured, with smaller T2 values indicating less fat content. Shoulders were evaluated on the basis of active range of motion (ROM), Constant and University of California Los Angeles Shoulder Rating Scale scores, shoulder external rotation strength with the arm at the side, and rotator cuff integrity on postoperative MRI. A total of 103 patients (103 shoulders) with a mean age of 65 ± 9 years (range, 42 to 83 years) were included, of whom 52 were male and 51 were female. There were 13 partial, 18 small, 35 medium, 33 large, and 4 massive tears. Concomitant subscapularis tears were observed in 35 shoulders. Overall, ROM, clinical scores, and external rotation strength significantly improved postoperatively. Retears were found in 27 shoulders (26%). External rotation strength significantly improved postoperatively only in shoulders without a retear. Among shoulders without a retear, the postoperative T2 values of the supraspinatus and infraspinatus were significantly smaller than the preoperative values (p < 0.001 for both); however, no improvement was seen in shoulders with a retear. Shoulders with successful repair demonstrated significantly smaller T2 values postoperatively as well as significantly improved external rotation strength. Fatty degeneration of the cuff muscles can be reversed, at least in part, and muscle strength improves in shoulders with successful repair. Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Relationship between strength training and shoulder pain in male and female water polo players.

The objective of this study was to assess the effect of two different strength-training methods on both male and female water polo players' performance and shoulder pain. The players were randomly allocated to a maximum strength (MS: 14 males, 8 females) or power strength (PS: 13 males, 8 females) training group. Before and after the intervention, we assessed player's anthropometric characteristics, shoulder internal and external rotation strength, hand grip strength, upper body strength, countermovement jump height, throwing velocity, swimming speed, shoulder pain on a visual analogue scale (VAS), wellness, and rate of perceived exertion per session. We observed no significant improvement (P<0.05) in specific skills but enhancement in hand grip strength in male players. In female players in the MS group, throwing speed and bench press weight decreased significantly (P<0.05). Shoulder external rotation strength at 240°/sec in male MS group players and shoulder external rotation strength at 60°/sec in female PS group players decreased significantly (P<0.05). In addition, from the first to the last week, shoulder pain increased significantly (P<0.05) in all players. Inverse correlations (P<0.05) were found between VAS and shoulder rotation strength in males in the PS group, and between wellness and shoulder internal rotation strength in men in the MS group and women in the PS group. We found that both MS and PS training did not enhance performance and increased shoulder pain in male and female water polo players.

Length-Tension Differences Between Concentric and Eccentric Shoulder Rotation Strength.

Giordano, KA, Cassidy, MM, and Oliver, GD. Length-tension differences between concentric and eccentric shoulder rotation strength. J Strength Cond Res 38(2): 253-258, 2024-Eccentric contractions generally produce more force than concentric contractions. However, if length-tension relationships affect both contractions equally remains unknown. Therefore, our purpose was to compare concentric versus eccentric shoulder external and internal rotation strength across a continuous 90° arc. Fifty-two physically active individuals performed isokinetic concentric and eccentric shoulder external rotation and internal rotation through a 90° arc (forearm horizontal to forearm vertical) with the shoulder elevated in both the frontal and scapular planes. Statistical parametric mapping analysis compared concentric and eccentric trials within subjects. Frontal plane eccentric external rotation torque was greater than concentric 30°-90° (p < 0.01) external rotation, and concentric external rotation torque was greater 5°-15° external rotation (p = 0.01). Frontal plane, eccentric internal rotation torque was greater than concentric 15°-55° external rotation (p < 0.01), and concentric torque was greater at forearm horizontal (p = 0.05) and 70°-90° external rotation (p < 0.01). Scapular plane eccentric external rotation torque was greater than concentric 30°-90° external rotation (p < 0.01) and concentric external rotation torque was greater 5°-20° external rotation (p < 0.01). Scapular plane eccentric internal rotation torque was greater than concentric 15°-60° external rotation (p < 0.01), and concentric torque was greater at forearm horizontal (p = 0.05) and 78°-90° external rotation (p = 0.02). Coaches, clinicians, and researchers should interpret data from studies reporting isokinetic data with the understanding that isokinetic peak strength values are not comparing the same muscle length and are not an appropriate measure for all muscle lengths. Furthermore, shoulder stability is affected through decreased eccentric force production at end ranges of shoulder rotation.

Injury, Training, Biomechanical, and Physiological Profiles of Professional Breakdancers.

Breakdancing or breaking will enter the Olympics in 2024, however, there is a paucity of literature exploring the epidemiology, demands, and performance. The purpose of this study was to describe injury and training profiles, along with the results of a short performance test battery, in a group of elite breakers. Cross-sectional study (retrospective). Fourteen breakdancers (breakers) (4 Bgirls, 10 Bboys) participated in an interview regarding their injury and training history, endurance test (cycle VO2max testing), counter movement jump, squat jump, drop jump, isometric hip abduction, adduction, shoulder external and internal rotation strength testing on a fixed-frame dynamometer. Breakers were divided into elite (n=10) and developing (n=4) based on their qualification for a world finals competition; Wilcoxen rank sums were used to compare the two groups, or in the case of strength testing between those with and without an injury history. The breakers had a median 11.0 [10.0 - 14.0] years breaking experience and trained 24.4 [20.5 - 30.0] hours per week. The knee was the most commonly injured body part and most frequently injured joint, with the thigh being the most common site for muscle injuries. There were no differences in endurance testing or jump height testing results between elite and developing breakers. There was no difference in shoulder external or internal rotation strength between athletes with a history of shoulder injury and those without. Similarly, there was no difference in hip abduction or adduction strength in those with a history of hip injury and those without. The results of this study should be viewed with caution due to the small sample size. However, this study is the first to publish functional and physiological descriptives on breakers. The authors hope these results support clinicians treating breakers as well as encourages future research related to breaking. 2b.

Blood Flow Restriction Training in Patients With Rotator Cuff Tendinopathy: A Randomized, Assessor-Blinded, Controlled Trial.

To investigate the effects of low-load blood flow restriction (BFR) training on shoulder muscle thickness, rotator cuff (RC) strength, and shoulder symptoms in patients with RC tendinopathy. A randomized, assessor-blinded, controlled trial. Physiotherapy clinic at a university. Twenty-eight patients were randomized into an 8-week (2 times/week) shoulder rehabilitation, that is, BFR or non-BFR group. BFR training. (1) RC, deltoid, scapula retractor, and biceps muscle thicknesses and shoulder internal rotation (IR) and external rotation (ER) strengths. (2) Shoulder pain/function. The BFR group had a greater increase in biceps muscle thickness ( P = 0.002) and shoulder IR strength at 60 degrees/s ( P = 0.040) than the non-BFR group. No differences between the 2 groups were observed in other measurements. Significant improvements in supraspinatus, infraspinatus, and scapula retractor muscle thicknesses and in shoulder ER and IR strengths were observed over time in both the groups (all P < 0 .05). Also, shoulder pain decreased and shoulder function increased over time in both the groups (all P < 0 .05). Low-load BFR training resulted in a greater increase in biceps thickness and shoulder IR strength compared with the non-BFR group in patients with RC tendinopathy. However, there was no superiority of either exercise training regarding the RC, scapula retractor, deltoid muscle thicknesses, or improvements in shoulder ER strength and shoulder pain/function. The study was registered in ClinicalTrials.gov named Blood Flow Restriction Training in Patients with Shoulder Pain and the registration number is NCT04333784.

Biomechanical and functional analysis of the shoulder complex and thoracic spine in patients with subacromial impingement syndrome: A case control study.

The motions of the shoulder are mainly carried out through the glenohumeral joint, but are also assisted by the scapulothoracic joint. Therefore, changes in the biomechanics of the thoracic spine and scapula affect the function of the shoulder. However, there is limited information on the biomechanical and functional characteristics of the shoulder complex and thoracic spine in patients with subacromial impingement syndrome (SIS). In this study, the biomechanical and functional characteristics of the shoulder complex and thoracic spine were analyzed in patients with SIS compared to healthy individuals. A total of 108 participants were included in this study. Participants were classified into 2 groups, the SIS (n = 55) and healthy (n = 53) groups. The shoulder and thoracic range of motion (ROM), scapular position, and isokinetic shoulder strength were measured in all participants. The shoulder ROM was significantly decreased in the SIS group compared to the healthy group (P < .001). The thoracic spine ROM showed significantly limited extension in the SIS group (P < .001). The scapular position showed significantly increased anterior tilting (P = .005), internal rotation (P = .032), protraction (P < .001), and decreased upward rotation (P = .002) in the SIS group. The isokinetic shoulder external rotation (P < .001) and abduction (P < .001) strength were significantly lower in the SIS group. Patients with SIS showed reduced shoulder ROM and end-range extension of the thoracic spine compared to healthy individuals, and the scapula was in a more anterior-tilted, protracted, and downward rotated position. In addition, it showed lower external rotation and abduction strength. These results suggest the need for interventions to improve the limited thoracic extension and altered scapular position, which may affect shoulder ROM and muscle strength in the rehabilitation of patients with SIS.

Effect of 8-week Shoulder External Rotation Exercise with Low Intensity and Slow Movement on Infraspinatus.

Generally, low-intensity training is recommended as selective training of the infraspinatus muscle. This study aimed to investigate whether an 8-week intervention of low-intensity, slow-movement, external rotation exercise of the shoulder led to an increase in muscle strength with shoulder external rotation and cross-sectional area (CSA) infraspinatus muscle. Sixteen healthy male volunteers were randomly assigned to the low-intensity and slow-movement (LS) group (N = 8) or the normal-intensity and normal-speed (NN) group (N = 8). The LS and NN groups performed shoulder external rotation exercises with low intensity and slow movement, and normal intensity and normal speed, respectively. The exercise session consisted of three sets of 10 repetitions, which were performed three times per week for 8 weeks. We measured the CSA of the infraspinatus and muscle strength of the shoulder external rotation before and after the 8-week intervention. A significant increase in infraspinatus CSA from baseline to 8 weeks was found in the LS group (7.3% of baseline) but not in the NN group. No significant differences were found in the muscle strength of shoulder external rotation. Our results suggest that low-intensity exercise of the infraspinatus is effective for muscle hypertrophy when performed with slow movement. This finding may help patients who should avoid excessive stress in the early phase of rehabilitation.

The Longitudinal Mediating Influence of Maturation on the Relationship Between Strength and Performance in Male Youth Swimmers.

To examine the longitudinal relationships between shoulder internal and external rotation (IR and ER) strength, maturity status, and swim performance (aim 1). To determine whether maturity status mediated (partially/fully) the relationship between shoulder IR/ER strength and performance in age-group swimmers (aim 2). Using a repeated-measures design, anthropometrics, maturity status, shoulder IR/ER strength, and 200-m front-crawl velocity were assessed over 3 competition seasons in N = 82 Australian male competitive swimmers (10-15y). For aim 1, linear mixed models examined longitudinal relationships between assessed variables. For aim 2, causal mediation analyses examined proportional (in)direct contributions of maturity status between shoulder IR strength and swim performance. For aim 1, linear mixed models identified a significant relationship between shoulder IR strength and swim performance over time (F1,341.25 = 16.66, P < .001, marginal R2 = .13, conditional R2 = .91). However, maturity status was influential (ΔAkaike information criterion = -75.8, χ2 = 19.98, P < .001), suggesting removal of the shoulder IR strength-swim velocity relationship (F1,214.1 = 0.02, P = .88). For aim 2, mediation analyses identified maturity status as fully mediating the shoulder IR strength-swim velocity relationship (92.30%, P < .001). Shoulder IR and ER strength did not account for variance in longitudinal age-group swim performance independent of maturity status. Interindividual differences in maturity status fully explained the relationship between shoulder IR/ER strength and swim performance. For practitioners, findings promote the need to account for maturation status and question the rationale for upper-limb strength assessment during maturational years.

Functional Performance Tests Reveal Promising Results at 6 Months After Shoulder Stabilization Surgery.

Although athletes are mostly allowed to return to play 6 months after shoulder stabilization surgery, there are inadequate data about their functional status during this period. Performance tests would reveal insufficiency in the functional capacity of shoulder 6 months after stabilization surgery. Prospective cohort study. Level 3. A total of 32 male athletes with arthroscopic anterior capsulolabral repair (AACR) were included in the study. Shoulder internal and external rotator (IR-ER) strength was assessed using isokinetic dynamometer at 60°/s and 180°/s angular velocities preoperatively and 6 months postoperatively. Shoulder function was assessed with closed kinetic chain upper extremity stability (CKCUES) test, Y balance test-upper quarter (YBT-UQ), and unilateral seated shot-put test (USSPT) at 6 months postoperation. Western Ontario shoulder instability index (WOSI) and Tampa scale of kinesiophobia (TSK) were used for the self-assessment of the shoulder. Mixed-model ANOVA was used to analyze the changes in the IR-ER strength on both shoulders. Limb symmetry index (LSI) was calculated for the IR-ER strength, YBT-UQ, and USSPT scores. Shoulder IR strength was higher at 6 months postoperatively compared with preoperatively. The LSI was 76.4% and 76.6% for ER strength, and 94.2% and 94% for IR strength at 60°/s and 180°/s angular velocities, respectively, at the postoperative 6 month timepoint. The mean CKCUES test score was 21.8 ± 2.6 touches and the LSI was 94.7% for the YBT-UQ and 102.5% for the USSPT. WOSI (P < 0.001) and TSK (P = 0.001) scores were significantly lower at 6 months postoperatively. Functional status of the patients with shoulder stabilization surgery improved considerably 6 months after surgery, yet they did not fully recover function. Exercise programs focusing on shoulder ER strength and shoulder performance should be emphasized after stabilization surgery.

Investigating The Association Between Supraspinatus Tendon Abnormality, Shoulder Pain and Isokinetic Strength in Elite Swimmers: A Cross-Sectional Study.

Shoulder pain is common among elite swimmers due to the tremendous stress over shoulders during swimming. Supraspinatus muscle is one of the major prime movers and stabilizers of shoulder and is highly susceptible to overloading and tendinopathy. An understanding of the relationship between supraspinatus tendon and pain; and between supraspinatus tendon and strength would assist health care practitioners for developing training regime. The objectives of this study are to evaluate 1) the association between structural abnormality of supraspinatus tendon and shoulder pain and 2) the association between structural abnormality of supraspinatus tendon and shoulder strength. We hypothesized that structural abnormality of supraspinatus tendons positively associated with shoulder pain and negatively associated with shoulder muscle strength among elite swimmers. 44 elite swimmers were recruited from the Hong Kong China Swimming Association. Supraspinatus tendon condition was evaluated using diagnostic ultrasound imaging and shoulder internal and external rotation strength was evaluated by the isokinetic dynamometer. Pearson's R was used to study the correlation between shoulder pain and supraspinatus tendon condition and to evaluate the association between isokinetic strength of shoulders and supraspinatus tendon condition. 82 shoulders had supraspinatus tendinopathy or tendon tear (93.18%). However, there was no statistically significant association between structural abnormality of supraspinatus tendon and shoulder pain. The results showed that there was no association between supraspinatus tendon abnormality and shoulder pain and there was a significant correlation between left maximal supraspinatus tendon thickness (LMSTT) and left external rotation/ concentric (LER/Con) and left external rotation/ eccentric (LER/Ecc) shoulder strength (p < 0.05) while internal rotation/ external rotation (IR/ER) ratio can also be a significant predicator on LMSTT >6mm (R2 = 0.462, F = 7.016, df = 1, p = 0.038). Structural change of supraspinatus tendon was not associated with shoulder pain, but could be a predictor on MSTT >6mm in elite swimmers.

Prediction of Scapular Dyskinesis through Strength and Range of Motion of Shoulder Joint Rotation in Competitive Boxers

Background and Aims This study investigated the relationship between shoulder rotation Range of Motion (ROM), shoulder rotation strength, and sports history with scapular dyskinesia in competitive boxers. Methods The present study was a descriptive correlational study performed on 60 male boxers (age: 24/01±3/90 years; weight: 74/61±6/73 kg; height: 176/97±6/06 cm; and sports history: 5/16±1/84 years) in Guilan. Scapular dyskinesia by lateral scapular slide test, shoulder rotation ROM using a manual goniometer, and shoulder rotation strength using a manual dynamometer were measured. Data were analyzed by Pearson and Spearman correlations and multiple regression analysis. Results There were significant correlations between sports history (p= 0.001; r=0.589), shoulder internal rotation ROM (p=0.040; r=-0.255), shoulder external rotation ROM (p=0.001; r=0.486), shoulder internal rotation strength (p= 0.009; r=0.334), and shoulder external rotation strength (p=0.001; r=-0.620) and scapular dyskinesia. Regression analysis showed that 63.1% of scapular dyskinesia changes were related to the independent variables mentioned in this study. Conclusion It can be concluded that there is a significant relationship between shoulder rotation ROM, shoulder rotation strength, sports history, and scapular dyskinesia. Therefore, by strengthening and improving the scapular stabilizing muscles and consequently improving the shoulder rotation strength and shoulder rotation ROM in boxers, scapular dyskinesia or its intensification can be prevented.

Paper 11: Utility of Objective Testing for Initiation of a Throwing Program Following Shoulder and Elbow Surgery in Competitive Baseball Players

Paper 11: Utility of Objective Testing for Initiation of a Throwing Program Following Shoulder and Elbow Surgery in Competitive Baseball Players

The Effect of Exercise Therapy Interventions on Shoulder Pain and Musculoskeletal Risk Factors for Shoulder Pain in Competitive Swimmers: A Scoping Review.

Shoulder pain is the main cause of missed or modified training in competitive swimmers. Exercise therapy can improve the outcomes, yet uncertainty exists regarding the characteristics of these interventions. The primary aim was to describe the evidence base relating to the effectiveness of exercise therapy interventions on shoulder pain and shoulder musculoskeletal risk factors for shoulder pain in swimmers. The secondary aim was to identify gaps in the literature and provide recommendations for future research and practice. A scoping review methodology was applied through the search of MEDLINE, PubMed, Scopus, Web of Science, and CINAHL databases. The authors included any research studies (except clinical commentaries and conference papers) that assess the effect of exercise therapy on shoulder pain and musculoskeletal risk factors for shoulder pain in swimmers. The literature was critically appraised using the Modified Down and Black checklist. From 452 papers identified, 14 studies were included in this review. An exercise program of 6 to 8 weeks, including strengthening exercises (shoulder external rotator and scapula retractor muscles) and stretches (pectoral muscles), can decrease the incidence of shoulder pain in swimmers. Furthermore, a combination of exercises and stretches with manual therapy techniques can help to decrease shoulder pain in injured swimmers. Regarding risk factors, a strengthening program of more than 12weeks increased shoulder external rotation peak force, endurance, and external rotation/internal rotation ratio; however, this was not associated to decreases in pain. Finally, open kinetic chain exercises and a dry-land program are superior to close kinetic exercises and water training for improving shoulder external rotation strength and endurance. Exercise therapy has positive effects on reducing the incidence of shoulder pain, the management of shoulder pain, and improving shoulder musculoskeletal risk factors in competitive swimmers. However, due to methodological limitations of the studies, caution must be used when applying these results in practice. Future research should focus on high-quality randomized controlled trials for prevention and management of shoulder pain in swimmers.

Verification of Shoulder External Rotators Strength Measurement Using a Suspension Scale.

BackgroundOf the shoulder external rotators, the infraspinatus and teres minor are the key muscles that contribute to the dynamic stability of the shoulder. It is crucial to properly measure the strength values to evaluate muscle function and training load for shoulder external rotators. A suspension scale (SPS) can measure the mass of the suspended object, and it may be possible to apply it to measure strength. However, the utility of strength measurements using an SPS has not been clarified in previous studies. In this study, we aimed to investigate the intra-rater reliability of measuring the strength of shoulder external rotators using an SPS and the relationship between strength measurement using an SPS and a handheld dynamometer (HHD).MethodologyThe participants were 10 healthy males with 20 shoulders (24.5 ± 2.5 years old; height = 172.8 ± 5.4 cm; weight = 69.6 ± 8.1 kg). Upper extremity strength was measured at 90° shoulder abduction, 90° external rotation, 0° horizontal adduction/abduction, 90° elbow flexion, and 0° forearm pronation/supination in the prone position. The isometric strength of shoulder external rotation was measured with the SPS and HHD, and one examiner measured the maximum strength value. The intra-rater reliability of the two methods using SPS and HHD was evaluated using the intraclass correlation coefficient (ICC1,2), standard error of measurement (SEM), minimum detectable change (MDC), and Bland-Altman analysis. The relationship between the SPS and HHD was calculated as the correlation coefficient between the strength values of SPS and HHD.ResultsThe intra-rater reliability of the strength measurement of shoulder external rotators using SPS was ICC1,2 0.98 (95% confidence interval = 0.95-0.99), and SEM and MDC were 0.3 and 0.9, respectively. The measurements using SPS had no fixed and proportional biases. A significant positive correlation was observed between SPS and HHD (r = 0.94, p < 0.01).ConclusionsThe SPS is an alternative to the HHD for measuring the strength of shoulder external rotators. Thus, measuring the strength of shoulder external rotators using an SPS may be applied as a cost-effective and portable assessment method for shoulder function.

Effect of Eight Weeks of Corrective Exercises on Scapulohumeral Rhythm, Isometric Strength of Shoulder Girdle Muscles and Functional Stability in Volleyball Players With Scapular Downward Rotation Syndrome

Background and Aims Movement impairment is common among overhead athletes and can make them susceptible to shoulder injuries. This study aims to invesigate the effect of an eight-week corrective exercise program based on Sahrmann’s approach on scapulohumeral rhythm, isometric strength of shoulder girdle muscles, and functional stability in volleyball players with scapular downward rotation syndrome (SDRS). Methods The is a quasi-experimental study with a pre-test/post-test design. Participants were 34 volleyball players with SDRS who were randomly divided into two equal groups of training (n=17) and control (n=17). Participants were selected based on observance of SDRS under the scapular dyskinesis test (SDT) in both flexion and abduction states, Kibler’s lateral scapula slide test (LSST), and scapulohumeral rhythm assessment. Before exercises, range of motion (ROM), isometric strength of shoulder girdle muscles, scapulohumeral rhythm, and functional stability were evaluated in both groups. Then, the training group performed the corrective exercises for eight weeks, three sessions per week. The control group performed no exercise and had their daily activities. At the end of training, post-test assessments were codncuetd in both groups. For the evaluation of isometric strength and ROM, a manual dynamometer and a goniometer were used, respectively. Scapulohumeral rhythm was measured at 4 positions (0, 45°, 90°, and 135°) with two inclinometers, and the Y-Balance Test Upper Quarter was used to measure the functional stability of the upper extremity. Paired sample t-test was used to compare the pretest and posttest means, and independent t-test was used to compare the differences between the two groups. The significance level was set at 0.05. Results After 8 weeks of training program, there were significant increase in the strength of the isometric strength of shoulder external rotaion (P=0.003), upper trapezius (P=0.001), middle trapezius (P=0.027), lower trapezius (P=0.001), and serratus anterior (P=0.002) as well as scapulohumeral rhythm at 0-45° (P=0.012), 45-90° (P= 0.025), and 90-135° (P= 0.037) abduction; the ROM of the shoulder flexion (P=0.002), abduction (P= 0.001), internal rortation (P= 0.001) and external rotaion(P= 0.004); and pectoralis minor muscle length (P= 0.001) compared to pre-test scores in the training group. Moroever, the functional stability of the upper extremity after training program increased significantly in the training group (P=0.001), but the training program had no significant effect on the strength of shoulder internal rotaion (P=0.165), rhomboid muscule strength (P=0.283) and supraspinatus muscule strength (P=0.214). In the post-test phase, between group comparison showed a significant difference in scapularhumeral rhythm, functional stability, ROM, pectoralis minor length, and strength of trapezius, serratus anterior, and strength of shoulder external rotation between the control and training groups (P&lt;0.05), but no significant difference was observed in the strength of supraspinatus and rhomboid muscles and strength of shoulder internal rotation (P&gt;0.05). Conclusion Eight weeks of corrective exercise program based on Sahrmann’s approach can improve the functional stability of the upper etermity, the scapulohumeral rhythm, and isometric strength of shoulder girdle muscles in volleyball players. This exercise protocol is recommended as an effective method to improve alignment and performance in athletes with SDRS.

Differences in Shoulder Internal Rotation Strength Between Baseball Players With Ulnar Collateral Ligament Reconstruction and Healthy Controls.

Background:Studies have indicated decreased shoulder internal rotation (IR) and external rotation (ER) strength in the throwing limb of baseball players after ulnar collateral ligament injury. There is limited evidence on the recovery of shoulder rotation strength after primary ulnar collateral ligament reconstruction (UCLR).Hypothesis:At the time of return to throwing, baseball players who underwent UCLR would demonstrate decreased IR and ER shoulder strength in the throwing arm as compared with healthy baseball players.Study Design:Cross-sectional study; Level of evidence, 3.Methods:Male competitive high school and collegiate baseball athletes participated in this study. Athletes who underwent UCLR were compared with healthy controls who were matched by age, height, weight, and position. Bilateral isometric shoulder ER and IR strength was measured using a handheld dynamometer for all participants at the time of initial evaluation (UCLR group) and throughout the course of a season (healthy group). Independent t tests were run to calculate mean differences in ER and IR shoulder strength between the groups, with significance set at P < .05.Results:A total of 86 baseball athletes participated in this study (43 UCLR group, 43 healthy group). At the time of return to throwing (mean ± SD, 194 ± 30 days postoperatively), the 2 groups demonstrated no significant differences in nonthrowing arm ER or IR strength (P = .143 and .994, respectively). No significant difference was found between groups for throwing arm ER strength (P = .921); however, the UCLR group demonstrated significantly less throwing arm IR strength than the healthy group (144.2 ± 27.8 vs 157.6 ± 27.1 N; P = .023).Conclusion:The results of this study demonstrate that throwing arm rotator cuff strength may not fully recover before the initiation of a return-to-throwing program after UCLR. These data provide a potential framework for clinicians to assist in the management and exercise prescription of the baseball athlete after UCLR and before medical release and the initiation of a return-to-throwing program.

Rate of improvement in shoulder strength after anatomic and reverse total shoulder arthroplasty.

BackgroundThe rate at which patients regain shoulder strength after anatomic and reverse total shoulder arthroplasty (TSA) is unknown. In this study, we aimed to quantify differences in the timeline during which patients gained shoulder strength after primary anatomic and reverse TSA.MethodsWe retrospectively reviewed prospectively collected data from 374 shoulders after primary anatomic TSA (aTSA) and 601 shoulders after primary reverse TSA (rTSA). Postoperative improvement in external rotation (ER) strength and forward elevation (FE) strength from baseline was assessed at 3 months, 6 months, 1 year, and 2 years. Percent change in mean shoulder strength between each time point was determined for anatomic and reverse groups separately. A handheld dynamometer was used to assess ER strength with the involved shoulder in 0° ER, 0° abduction, and the elbow in 90° flexion and FE strength with the involved shoulder in the scapular plane at 30° of flexion and 30° of abduction.ResultsBoth aTSA and rTSA groups ceased to have statistically significant gains in FE strength after 1 year postoperatively. In contrast, patients continued to have statistically significant gains in ER strength between 1 year and 2 years postoperatively after rTSA (P = .001), but not after aTSA (P = .476). Both aTSA and rTSA groups saw improvement in strength in both ER (+32.1% and +51.4%, respectively) and FE (+38.3% and +90.3%, respectively) at 2-year follow-up. The aTSA group’s ER and FE strength increased the most between 3 and 6 months (+16.2% and +35.7%, respectively). In contrast, the rTSA group gained the most ER strength between 6 months and 1 year (+14.8%) and the greatest FE strength between baseline and 3 months (+40.3%).ConclusionPatients gain ER strength earlier and FE strength later after aTSA compared with rTSA. Most gains in strength occurred in the first year. However, statistically significant gains in shoulder ER strength in the rTSA group continued between 1 year and 2 years postoperatively, suggesting that 2-year follow-up may be inadequate to capture the full benefits of rTSA on shoulder strength. The results of this study provide insight into the timeline of strength recovery after aTSA and rTSA that will help inform patient counseling and future study design.

Change in shoulder external rotation strength and motion after lower trapezius transfer to the infraspinatus in children with obstetric brachial plexus palsy.

Quantifying changes in shoulder external rotation range of motion and strength after lower trapezius transfer in children with obstetric brachial plexus palsy (OBPP). This prospective study included five children with sequelae of OBPP, with a mean age of 6.4 years (range: 4-12 years) who underwent lower trapezius tendon transfer to restore active external rotation (ER) of the shoulder. Pre-operatively and at a 12-month follow-up assessment, we analyzed the passive and active shoulder ER, the modified Mallet score, and the shoulder rotator muscles strength using an isokinetic device. Clinical parameters improved significantly after trapezius transfer pre-operative passive ER from -8° (range: -20-0°) to 37° (range: 15-50°) (p = 0.035), the modified Mallet score from 13 (range: 10-15) to 18 (range: 17-19) (p = 0.035). Strength testing revealed improved ER muscle strength in all five cases; the mean Peak Torque increased from 1.95 to 4.46 N·m, albeit non-significantly (p = 0.062). Two patients exhibited a winged scapula post-operatively. Lower trapezius transfer seems encouraging to restore shoulder external rotation in OBPP children but with non-significant strength improvement. 18/07/31/5783, December 22, 2018.

Professional Baseball Player Type and Geographic Region of Origin Impacts Shoulder External and Internal Rotation Strength.

BackgroundShoulder strength deficits are implicated in arm injuries and performance deficits in baseball players.PurposeTo characterize shoulder external (ER) and internal (IR) rotation strength in professional baseball players, and compare strength across player type (pitchers, position players) and geographic origin (North America, Latin America).Study DesignCross-sectional.MethodsMinor league professional baseball players from North America and Latin America (n=242; age=22.4±2.3 years; n=135 pitchers and n=107 position players; n=162 North American and n=80 Latin American players) volunteered at spring training. Bilateral shoulder IR and ER isometric strength was measured in sitting with the arm at the side using a handheld dynamometer stabilized on a wall via a specialized jig. Strength was normalized to body weight, and compared using t-tests between player type and geographic area of origin (p < 0.05).ResultsPosition players had greater strength in ER, IR and ER:IR (ER:0.7-2.7N/kg; IR:1.3-3.8N/kg; ER:IR ratio 0.36-1.22) compared to pitchers (ER:0.5-2.5N/kg; IR:0.6- 4.2N/kg; ER:IR ratio 0.44-1.16) on the throwing arm. North American pitchers had lower ER [MD= -0.4 (95%CI:-0.7,-0.2);p=0.002] and IR [MD= -0.2 (95%CI:-0.4,-0.1);p=0.006] than Latin American pitchers on the throwing arm. There were no differences between geographic groups for position players.Discussion/ConclusionsPlayer position and geographic origin influence shoulder rotational strength values in professional baseball players. Position players have 14 – 20% higher ER and IR isometric strength than pitchers. Moreover, Latin American pitchers exhibited 11.8% greater ER strength and 16.7% greater IR strength as compared to North American pitchers. Normative values can be used to determine player deficits, declines in performance, and targets for return to play after injury.Level of EvidenceLevel II