Hamstring strain injuries are one of the most common non-contact injuries in sports and have a high recurrence rate that can cause result in time away from competition or impaired performance on return to competition for athletes. 1,2 The causes of the hamstring strain injuries are multifactorial. It is believed that general muscle properties, including passive viscoelastic parameters (muscle tone, elasticity, and stiffness), help to avoid injuries and overtraining. 3 Each viscoelastic parameter plays an important role for enhancing muscular performance (including improving running speed, jumping) and reducing the onset of fatigue and risk for injury or recurrence. 4-6 Furthermore, they are also valuable in clinical use to evaluate treatment efficacy and progression of the symptoms. 3 The mechanical properties of muscles are described by their viscoelasticity when skeletal muscles are in a steady-state condition with no voluntary contraction. 7 Muscle tone is generated actively by the nervous system and passively by the muscle's intrinsic viscoelastic properties. The intrinsic aspects of muscle tone comprise passive stiffness and the inherent mechanical properties of the tissues. 7 Muscle elasticity represents the ability of the muscle to recover its initial shape after a contraction

Context: The wall slide exercise is commonly used in clinic and research settings. Theraband positioning variations for hip exercises are investigated and used, but theraband positioning variations for upper extremity wall slide exercise, though not commonly used, are not investigated. Objective: To investigate the effect of different theraband positions (elbow and wrist) on scapular and shoulder muscles' activation in wall slide exercises and compare them to the regular wall slide exercise for the upper limbs. Study Design: Descriptive Laboratory Study. Setting: University Laboratory Patients or Other Participants: 20 participants with healthy shoulders Interventions: Participants performed regular and two different variations of wall slide exercises (theraband at wrist and theraband at elbow) in randomized order. Main Outcome Measures: Surface EMG activity of the trapezius muscles (upper [UT], middle [MT], and lower trapezius [LT]), infraspinatus (IS), middle deltoid (MD), and serratus anterior (SA). Results: Regular wall slide exercise elicited low activity in MD and moderate activity in SA muscles (32% MVIC), while theraband at wrist and elbow variations elicited low activity in MT, LT, IS, and MD muscles and moderate activity in SA muscles (46% and 34% MVICs, respectively). UT activation was absent to minimal (0–15% MVIC) in all wall slide exercise variations. Theraband at wrist produced lower UT/MT, UT/LT, and UT/SA levels. Conclusion: In shoulder rehabilitation, clinicians desiring to activate scapular stabilization muscles should consider using theraband at wrist variation; clinicians desiring to achieve more shoulder abduction activation and less scapular stabilization should consider theraband at elbow variation of upper extremity wall slide exercise.

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Context: Weight-bearing test (WBT) is a noninvasive quantitative test which has been used recently to determine loading capability of the individuals. The aim of this study was to strengthen the evidence for using the WBT test for measuring weight-bearing capacity of the upper-extremity with the specific objective of examining the internal and external responsiveness and concurrent validity of the test in patients with triangular fibrocartilage complex injury. Design: Single-group repeated measures. Methods: Internal responsiveness was assessed using effect size statistics. The correlation coefficient was used to examine external responsiveness by testing 5 hypotheses regarding predefined correlations between the changes in the measurements. Concurrent validity was evaluated by analyzing correlations between the WBT and other measurements. Thirty-one patients with triangular fibrocartilage complex injury were included for the analysis of the concurrent validity. Eighteen patients who completed all measurements at baseline and at 3-month follow-up enrolled for the responsiveness analysis. Measurements included the WBT, pain intensity, grip strength, and upper extremity functional level. Results: The WBT test was able to detect statistically significant changes in weight-bearing capacity between baseline and follow-up (P = .0001). The effect size of the WBT was large. Three out of 5 hypotheses (60%) were confirmed, a good correlation was found between changes scores of the WBT and grip strength (r = .478; P < .05). There were significant correlations between the WBT and other measurements (r value range from −.401 to .742; P < .05). A higher correlation was found between the WBT and grip strength (r = .742; P = .0001). Conclusions: The responsiveness and concurrent validity of the WBT test confirmed that it is able to measure change in weight-bearing capacity in patients with triangular fibrocartilage complex injury.

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Background: Shoulder bracing is very common in musculoskeletal rehabilitation.Objective: In this study, the positioning efficacy of shoulder support braces was investigated by analyzing their three-dimensional kinematic properties, as well as their perceived comfort was investigated with user ratings. Study design: A randomized repeated-measures study. Methods: Seventeen asymptomatic participants were included. Scapular, humeral, and thoracic kinematics for all participants were measured using an electromagnetic tracking device in 6 experiments in randomized order: no brace, neutral brace, abduction brace, internal rotation brace, 15-degree external rotation brace (ER15-B), and 30-degree external rotation brace (ER30-B). Also, comfort ratings were obtained during each session. Results: Internal rotation brace achieved a mean of 29.34°of humerothoracic internal rotation while providing increased scapular internal rotation and upward rotation (p , 0.05). Abduction brace achieved a mean of 45.39°of humerothoracic and 39.58°of glenohumeral elevation coupled with increased scapular upward rotation, posterior tilt, and humeral internal rotation (p , 0.05). 30-Degree external rotation brace achieved a mean of 33.25°of glenohumeral external rotation and resulted in increased scapular external rotation, upward rotation, posterior tilt, and humeral external rotation (p , 0.05). Abduction brace, internal rotation brace, ER15-B, and ER30-B moved the thoracic spine into a more axial rotation in the contralateral direction. Internal rotation brace, ER15-B, and ER30-B were rated more uncomfortable when compared with the no brace condition, with no significant differences observed among the braces. Conclusions: The positioning efficacy was enhanced when an abduction pillow and external rotation wedge were applied. Selection of commercially available shoulder support braces should involve consideration of whether it can achieve the desired position and orientation as well as its comfort profile.