Posterior Shoulder Endurance Test Research Articles

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

IntroductionReliable 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. MethodsThe 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. ResultsSuperior 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. ConclusionUsing 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.

Master swimmers with shoulder pain and disability have altered functional and structural measures.

Supraspinatus tendinopathy and shoulder pain are common in competitive youth swimmers; however, no studies have investigated clinical and structural factors contributing to shoulder pain and disability in master level swimmers. The objectives of this study were: 1) to determine the prevalence of shoulder pain and disability in master level swimmers, 2) to identify the most provocative special tests for shoulder pain, and 3) to determine if shoulder clinical and tissue specific measures, training variables and volume vary between those with and without shoulder pain, dissatisfaction and disability. Cross-sectional. Collegiate swimming facilities. Thirty-nine adult masters level swimmers were evaluated and included in the data analysis. A survey of demographics, training, and pain and disability ratings using the Penn Shoulder Score and Disability of Arm Shoulder Hand sports module. Swimmers underwent a clinical exam including shoulder passive range of motion (PROM), posterior shoulder endurance test (PSET), supraspinatus tendon structure and posterior capsule thickness. One-way ANOVAs were used to compare demographics, clinical and structural findings between those with significant pain, dissatisfaction and disability (+PDD) and those without (-PDD). Fifteen percent of subjects reported pain at rest, 28% with normal activities (eating, dressing), and 69% with strenuous activities (sports) and 50% reported disability. The +PDD group had less shoulder internal rotation (10°), less ER (8°), and completed less yardage per day and per year. There were significant differences in the supraspinatus tendon structure between the +PDD and -PDD groups. Masters swimmers with pain and disability are able to self-limit yardage and likely why they recorded less yardage. The reduced shoulder motion (IR and ER) without posterior capsule differences may be due to rotator cuff muscle/tendon restrictions and the supraspinatus tendon structure may indicate degeneration caused by previous overuse resulting in pain.

Intra-rater reliability, inter-rater reliability and minimal detectable change of the posterior shoulder endurance test in elite athletes

ObjectiveInvestigate intra-rater and inter-rater reliability of the posterior shoulder endurance test (PSET) and calculate minimal detectable change (MDC) to establish measurement properties and inform use of the PSET in practice. Study designTest-retest reliability. Setting: British Canoe Slalom National Training Centre. ParticipantsTwelve participants (7 male, 5 female; 22.5 ± 4.48 years; 73.4 ± 6.36 kg) were investigated by two physiotherapists with >10 years’ experience. Main outcome measureIntraclass correlation coefficients (ICC) were calculated for intra-rater reliability (ICC 3,1) and inter-rater reliability (ICC 2,1) and used to calculate MDC. ResultsIntra-rater reliability scores were 0.84 and 0.85 for rater A and B, respectively, with 95% confidence interval (CI) crossing moderate to excellent reliability for both raters (0.5–0.75 and > 0.9). Inter-rater reliability scores were 0.74 and 0.63 at baseline and follow-up, respectively, with 95% CI crossing poor to good reliability in both time points (<0.5 and >0.75). MDC95% for intra-rater scores was 6 repetitions, MDC95% for inter-rater scores was 8 repetitions at baseline and 9 repetitions at follow-up. ConclusionThe PSET has acceptable intra-rater reliability but further work is needed to narrow the CI to an appropriate level for inter-rater reliability. The MDC calculated helps clinicians interpret changes in tests scores.

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

ObjectiveThis investigation measured the reproducibility and discriminant validity of the Posterior Shoulder Endurance Test (PSET) on painful and non-painful populations. DesignReliability and validity study. SettingLaboratory setting. ParticipantsThirty subjects (male = 11; female = 19). Main outcome measuresTime 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. ResultsThere 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. ConclusionThe 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.

Changes in clinical measures and tissue adaptations in collegiate swimmers across a competitive season

Competitive swimmers incur shoulder pain and injury. Physical characteristics such as shoulder range of motion (ROM) and endurance and tissue adaptations such as posterior capsule thickness (PCT) may be risk factors in addition to high training volume. 1) To identify the most provocative special test and prevalence of positive special tests for shoulder impingement tests in a group of collegiate swimmers, (2) to assess shoulder pain and disability, internal rotation (IR) and external rotation, and horizontal adduction (HADD) ROM and posterior shoulder endurance longitudinally over a competitive collegiate season, and (3) determine if there is a relationship between swimming yardage, supraspinatus tendon organization, and PCT. Thirty Division III swimmers were tested poolside at the beginning (T1), middle (T2), and end (T3) of their season. Dependent variables included pain and disability, shoulder ROM, Posterior Shoulder Endurance Test (PSET) value, and PCT. Analyses of variance with follow-up t tests compared measures over time, and Pearson correlation coefficients were performed. Despite increased swimming yardage, disability was reduced from T1 to T3 (P = .003). There was a reduction in bilateral IR and HADD ROM from T1 to T3. PSET values increased on the right from T1 to T3 (P = .014). There was a significant positive correlation between swimming yardage at T1 and T2 and PCT at T3 (P = .034, P = .028). A loss of shoulder IR and HADD was observed across the season concurrent with less swimming-related disability, which may indicate a favorable adaptation. Improved PSET scores over the season is consistent with prior research linking endurance and less pain and disability.

Changes in Clinical Measures and Tissue Adaptations in Collegiate Swimmers Across a Competitive Season

Background: Due to high training volume, competitive swimmers incur shoulder pain and injury1, but certain physical characteristics, such as shoulder ROM and endurance, and tissue adaptations such as posterior capsule thickness (PCT) and supraspinatus tendon structure may also be risk factors. Decreased endurance and ROM have been found in competitive swimmers along with being related to pain2. However, no longitudinal studies have examined pain and disability, range of motion, training volume, shoulder endurance and tendon structure over the course of a competitive season.&#x0D; Purpose: The purpose of this study was to: 1) to assess shoulder pain and disability, internal rotation (IR) and external rotation (ER) and horizontal adduction (HADD) ROM, and posterior shoulder endurance longitudinally over a competitive collegiate season, and 2) determine if there is a relationship between swimming yardage, supraspinatus tendon organization and posterior capsule thickness.&#x0D; Methods: 17 male and 13 female Division III swimmers aged 19.6 ± 1.1 years participated. Pain and disability were assessed using the Penn Shoulder Score and the Disability of Arm Shoulder Hand sports module. Internal rotation (IR), external rotation (ER), and horizontal adduction (HA) were measured using a digital inclinometer. Shoulder endurance was measured using the Posterior Shoulder Endurance Test (PSET). Anterior, center, and posterior supraspinatus tendon images were collected by locating the anterior aspect of the tendon insertion and moving posteriorly. The ultrasound images were analyzed using custom MATlab software to quantify tissue organization. All measures were found in the beginning (T1), middle (T2), and end (T3) of the season. Repeated measure ANOVAs were used to compare longitudinal changes across time. If p-values were found to be ≤ 0.05, follow-up paired t-tests with Bonferroni corrections were used to compare T1, T2, and T3. This protocol was IRB-approved and participants signed a written consent form.&#x0D; Results: An increase in swimming yardage from T1 to T2 was followed by a significant decrease in yardage to finish the swimming season (Table 1). Disability decreased and endurance increased throughout the season with no observed changes in pain. IR and HA ROM decreased significantly between all timepoint comparisons. Tendon banding frequency did not change over time (Table 2).&#x0D; Discussion: Large amounts of IR during the pull phase and late initiation of ER during the recovery phase have been associated with a high risk of impingement4. The relationship between pain, disability, and range of motion may suggest that a reduction of IR could protect the swimmers’ shoulder by limiting impingement through the pull and recovery phases. However, further investigation is required to confirm. The lack of statistical significance longitudinally in tendon organization is not surprising since there were no changes in pain, a decrease in disability, and an increase in endurance.&#x0D; Conclusion/Clinical Relevance: Further research is required to understand the relationship between training volume, tendon organization, and disability. Collegiate swimmers demonstrate increased endurance and decreased disability over the course of the season. It may suggest that the loss of ROM is a positive adaptation and may be protective.

Reliability of Posterior Shoulder Endurance Test in Overhead Athletes

Reliability of Posterior Shoulder Endurance Test in Overhead Athletes

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 ± 1 Nm was used for females and 21 ± 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.

Improvements in Shoulder Endurance Following a Baseball-Specific Strengthening Program in High School Baseball Players

Background:The posterior shoulder muscles play key roles in maintaining shoulder function in throwing. Arm fatigue has been identified as a risk factor for shoulder and elbow pain in youth baseball pitchers. However, endurance of the posterior shoulder muscles in overhead athletes is not routinely examined or conditioned.Hypothesis:Upper extremity muscular endurance can be improved in adolescent baseball players during a 20-week preseason training program. Secondarily, strength will be improved. Finally, these improvements will be associated with maintenance of range of motion.Study Design:Cohort study.Methods:Fourteen baseball players (age, 16 ± 2 years) attended 3 supervised training sessions per week for 20 weeks. Strengthening of the upper extremity was performed with a specific progression that utilized readily available equipment. Testing was completed at baseline and at 4, 8, and 20 weeks. The posterior shoulder endurance test was performed to assess muscular endurance. Glenohumeral internal and external rotation range of motion and strength were measured.Results:Posterior shoulder endurance improved from 30 ± 14 repetitions at baseline to 66 ± 26 at 4 weeks and 88 ± 36 at 20 weeks (P < 0.05). Glenohumeral internal rotation range of motion and the glenohumeral internal/external rotation strength ratio remained similar over the course of the program.Conclusion:Implementation of a preseason training program effectively increased shoulder muscular endurance while maintaining strength ratios and range of motion throughout the 20-week program.Clinical Relevance:This program improved a key parameter known to be associated with shoulder function and injury risk. This study describes a simple clinical tool to assess muscular endurance of the posterior shoulder.