Angle-Specific Isokinetic Shoulder Rotational Strength Can be Reliably Assessed in Collision and Contact Athletes.

An increased understanding of rotational strength as a potential prognostic factor for injury in contact and collision athletes may be important in planning return to sport. The aim of this study was to (1) determine the test-retest reliability of clinically relevant, angle-specific rotational and peak torque measurements in a cohort of uninjured collision and contact athletes; (2) develop a normal descriptive profile of angle-specific rotational torque measurements in the same cohort; and (3) examine the effects of direction and joint angle on shoulder rotational strength interlimb asymmetries. Twenty-three collision and contact athletes were recruited for the interday reliability substudy and 47 athletes were recruited for the remaining substudies. We used intraclass correlation coefficients with 95% confidence intervals to quantify interday reliability of all variables. We used a 2-way repeated-measures analysis of variance to analyze differences in absolute interlimb asymmetries. Interday reliability for the isokinetic strength variables was good to excellent (0.78-0.90) on the dominant side and moderate to good (0.63-0.86) on the nondominant side. Maximum angle-specific torque (as well as peak torque) can be measured reliably in internally and externally rotated positions. A normal profile of clinically relevant, angle-specific shoulder rotational torque measurements for collision and contact athletes has been established which provides a reference when assessing shoulder strength in this population.

Biomechanical upper-extremity performance tests and isokinetic shoulder strength in collision and contact athletes.

The aim of this study was threefold (1) to assess the reliability of three upper-extremity performance tests: a countermovement push up, press jump and drop box land, performed on a set of dual-force plates (2) to examine whether there was an association between isokinetic dynamometry and the performance tests in a non-injured cohort of collision/contact athletes and (3) to establish a normal descriptive profile of the vertical ground reaction forces from the performance tests, in a cohort of contact/collision athletes. The study was split into two sub-sections; the inter-day reliability of three upper-extremity performance tests (n = 21) and a descriptive, correlation study investigating the relationship between isokinetic dynamometry and performance tests metrics (n = 39). We used intraclass correlation coefficients (absolute agreement, 2-way mixed-effects model) with 95% confidence intervals to quantify inter-day reliability of all variables. We used Pearson correlation coefficients to investigate associations between isokinetic strength and vertical ground reaction force asymmetry variables. Inter-day reliability was moderate-to-excellent for the upper-extremity performance tests (ICC 0.67-0.97). There was no statistically significant correlation between external and internal rotational peak torque and the variables of CPMU, PJ and BDL (r range = .02-.24).These upper-extremity tests are reliable for use with male contact/collision athletes.

Upper Limb Strength and Performance Deficits after Glenohumeral Joint Stabilization Surgery in Contact and Collision Athletes.

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.

Outcome Measures After Shoulder Stabilization in the Athletic Population: A Systematic Review of Clinical and Patient-Reported Metrics.

BACKGROUND: Athletic endeavor can require the "athletic shoulder" to tolerate significant load through supraphysiological range and often under considerable repetition. Outcome measures are valuable when determining an athlete's safe return to sport. Few data are available to guide a clinician's choice from the variety of measures available. PURPOSE: To describe the use of quantifiable objective outcome measures and patient-reported outcome tools after glenohumeral joint stabilization, specifically in an athletic population. The secondary aim of our study was to assess whether the method of measurement used was clearly described and standardized to aid clinical interpretation. STUDY DESIGN: Systematic review; Level of evidence, 4. METHODS: A systematic search of MEDLINE, Scopus, SPORTDiscus, and Web of Science databases was performed in December 2018 based on the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. After the application of selection criteria, a full review of identified papers, and screening of reference lists, a total of 62 studies were included in the review. All studies were independently appraised for quality, predefined data fields were populated and cross-checked for accuracy, and results were then summarized from these data fields. RESULTS: Of the 62 included studies, 94% used a quantifiable objective clinical outcome. A majority (85%) of the studies measured range of motion, 21% recorded muscle strength, 5% measured electromyographic activity, 5% examined shoulder kinematics, and 3% assessed joint proprioception after surgery. However, only 18% of the studies clearly described a standardized method of measuring the outcome. Nearly all (95%) of the studies used at least 1 patient-reported outcome measure. The Rowe score was most commonly used (35%). CONCLUSION: We must standardize and clearly describe the use of quantifiable objective outcome measures to aid clinical interpretation. A concerted effort should also be made to standardize the use of patient-reported outcome tools after shoulder stabilization in the athletic population.