Reliability of isokinetic decay slope is superior to using fatigue indices for shoulder horizontal abduction.

INTRODUCTION: Reliable and valid measurements for shoulder muscular endurance should be available for clinical use. The posterior shoulder endurance test offers a potential clinical assessment, but its construct validity isn't available. Since a criterion measure of muscular endurance is not available, this study's purpose was to determine a reliable method for testing shoulder muscular endurance using an isokinetic dynamometer. METHODS: The test-retest reliability, standard error measurement, and minimal detectable change were calculated on four different paradigms to quantify muscular fatigue using two isokinetic speeds (60°sec-1,180°sec-1). Calculation paradigms included peak torque fatigue index (FI), average torque FI, area-under-the-curve FI, and peak torque decay slope. Testing occurred on two days. Repeated measures analysis of variance compared the two peak torque decay slopes across both testing days. RESULTS: Superior reliability was found within the decay slope measurements at both 60°sec-1 (ICC = 0.941) and 180°sec-1 (ICC = 0.764) speeds, with the 60°sec-1 decay slope being the highest reliability between the two angular velocities. There was a greater amount of fatigue in the 60°sec-1 decay slope compared to the 180°sec-1 decay slope. CONCLUSION: Using the decay slope of isokinetic shoulder horizontal abduction at 60°sec-1 is a reliable method to validate other muscular endurance clinical measures. Rehabilitation specialists should utilize the decay slope of the isokinetic dynamometry to monitor responsiveness.

A systematic review of the measurement properties of the Pennsylvania Shoulder Score.

BACKGROUND: Pennsylvania Shoulder Score (PSS) is a patient-reported outcome measure (PROM) that is gaining use when examining shoulder-specific outcomes. To date, a systematic review of the PSS measurement properties has not been published. PURPOSE: To systematically locate, appraise, and synthesize the evidence concerning the measurement properties of the PSS. STUDY DESIGN: Systematic literature review. METHODS: A pair of raters conducted a literature search using pre-defined keywords from 5 databases (PubMed, CINAHL, SPORTdiscus, PsychINFO, Scopus) during the week of October 23, 2022. Critical appraisal of study design for psychometric articles was used to assess methodological quality and risk of bias. Measurement property data were synthesized with pooled estimates for the indices of test-retest reliability (ICC), standard error of measurement (SEM), minimal detectable change (MDC), Cronbach α (CA), effect size (ES), and standardized response means (SRM) calculated from applicable studies. RESULTS: A total of 13 articles met the inclusion criteria for this review. Methodological quality was agreed upon between the 2 raters with a weighted kappa of 0.77, and 9/13 of the articles were rated above 70%. Test-retest reliability of the PSS total score ranged between 0.90 and 0.94, and construct validity was high when compared to other shoulder-specific PROMs (0.75 < r > 0.96). Responsiveness of the PSS was large across all studies with few PSS subscales dropping to moderate. Pooled MDC90 of the total PSS was 12.13 points, and the pooled ES of the total PSS was 0.85. CONCLUSIONS: The scope of this review demonstrates positive measurement properties of the PSS as a reliable, valid, and responsive measurement of shoulder-specific PROM. However, there are few studies examining the measurement properties of the PSS and more research is needed to assess cross-cultural appropriateness and factor analysis of the questions contained in the PSS.

Reproducibility and discriminant validity of the Posterior Shoulder Endurance Test in healthy and painful populations.

OBJECTIVE: This investigation measured the reproducibility and discriminant validity of the Posterior Shoulder Endurance Test (PSET) on painful and non-painful populations. DESIGN: Reliability and validity study. SETTING: Laboratory setting. PARTICIPANTS: Thirty subjects (male = 11; female = 19). MAIN OUTCOME MEASURES: Time to failure (TTF) was the primary outcome measure to determine reliability of the PSET. Discriminant validity identified with receiver operator characteristic (ROC) curves utilized TTF separately in men and women since they used different loads. RESULTS: There were 25/30 subjects (painful = 12; non-painful = 13) tested a second time. ICC, SEM, and MDC90 ranged respectively from 0.77, 13.1 s, 30.6 s in the painful group to 0.85, 7.3 s, 17 s in the non-painful group. The male ROC curve AUC was 0.833 with 47 s resulting in the best combination of sensitivity = 0.833, and specificity = 0.80. The female ROC curve AUC was 0.633 with 46 s resulting in the best combination of sensitivity = 0.600 and specificity = 0.889 at 46 s. CONCLUSION: The PSET is a reliable way to measure shoulder girdle muscular endurance. These data suggest that the PSET discriminates painful and non-painful individuals better in men compared to women.

An electromyography study of muscular endurance during the posterior shoulder endurance test.

The primary purpose was to determine if there is a difference between the median frequency slopes of 5 posterior shoulder muscles during the initial portion of the Posterior Shoulder Endurance Test (PSET) at the 90° and 135° shoulder abduction positions. Fifty-five healthy volunteers (31 females) participated. The median frequency of the posterior deltoid (PD), upper trapezius (UT), middle trapezius (MT), lower trapezius (LT), and infraspinatus (INF) was measured during the PSET at 90° and 135° of shoulder abduction. External torque of 13 ±â€¯1 Nm was used for females and 21 ±â€¯1 Nm for males. A fixed effect multi-variable regression model was used to investigate the median frequency slopes. Males and females were analyzed separately. Median frequency slopes demonstrated fatigue in all 5 of the muscles. The PD fatigued greater than the UT in males (p = 0.0215) and greater than the LT in females (p = 0.008). The time to task failure (TTF) was greater at 90° than 135° for females and males (p = 0.016; p = 0.0193) respectively. The PSET causes fatigue in all of the muscles that were tested, with the PD fatiguing at a greater rate compared to one muscle for each sex. This investigation supports using TTF as a clinical measure of shoulder girdle endurance at 90° shoulder abduction.

Measurement Properties of the Lower Extremity Functional Scale: A Systematic Review.

STUDY DESIGN: Systematic review of measurement properties. BACKGROUND: Many primary studies have examined the measurement properties, such as reliability, validity, and sensitivity to change, of the Lower Extremity Functional Scale (LEFS) in different clinical populations. A systematic review summarizing these properties for the LEFS may provide an important resource. OBJECTIVE: To locate and synthesize evidence on the measurement properties of the LEFS and to discuss the clinical implications of the evidence. METHODS: A literature search was conducted in 4 databases (PubMed, MEDLINE, Embase, and CINAHL), using predefined search terms. Two reviewers performed a critical appraisal of the included studies using a standardized assessment form. RESULTS: A total of 27 studies were included in the review, of which 18 achieved a very good to excellent methodological quality level. The LEFS scores demonstrated excellent test-retest reliability (intraclass correlation coefficients ranging between 0.85 and 0.99) and demonstrated the expected relationships with measures assessing similar constructs (Pearson correlation coefficient values of greater than 0.7). The responsiveness of the LEFS scores was excellent, as suggested by consistently high effect sizes (greater than 0.8) in patients with different lower extremity conditions. Minimal detectable change at the 90% confidence level (MDC90) for the LEFS scores varied between 8.1 and 15.3 across different reassessment intervals in a wide range of patient populations. The pooled estimate of the MDC90 was 6 points and the minimal clinically important difference was 9 points in patients with lower extremity musculoskeletal conditions, which are indicative of true change and clinically meaningful change, respectively. CONCLUSION: The results of this review support the reliability, validity, and responsiveness of the LEFS scores for assessing functional impairment in a wide array of patient groups with lower extremity musculoskeletal conditions.