Author ORCID Identifier

https://orcid.org/0000-0002-1901-3763

Year of Publication

2020

Degree Name

Doctor of Philosophy (PhD)

Document Type

Doctoral Dissertation

College

Health Sciences

Department

Rehabilitation Sciences

First Advisor

Dr. Timothy L. Uhl

Second Advisor

Dr. Arthur J. Nitz

Abstract

Of the intrinsic factors responsible for non-traumatic shoulder pain, muscular endurance is often not measured by rehabilitation professionals due to the lack of available shoulder endurance measures. Measurement properties of the PSET have not been adequately assessed in previous studies. The purpose of this dissertation was to develop the clinical measurement properties of the Posterior Shoulder Endurance Test (PSET) so that it might be used as a clinical measure of shoulder muscular endurance.

Electromyography (EMG) offers the ability to identify which muscles in the posterior shoulder girdle are fatiguing during the PSET. Surface EMG of upper trapezius (UT), middle trapezius (MT), lower trapezius (LT), infraspinatus (INF), and posterior deltoid (PD) were obtained on healthy individuals during the PSET. Median frequencies across time identified nearly all muscles fatigued at a similar rate. Thus, the PSET is a global assessment of shoulder muscular fatigue.

The second aim of this dissertation examined the reliability and discriminant validity of the PSET in individuals with and without shoulder pain. Subjects were tested twice within 7-10 days. The Intraclass Correlation Coefficients (ICC) for the painful group was ICC = 0.77; non-painful group ICC = 0.85; and combined ICC = 0.80. Receiver operating characteristic (ROC) curve representing discriminant validity were calculated separately for males and females. The ROC for males had good discriminant validity (AUC = 0.833) and those with shoulder pain tended to fail in the PSET in less than 46 seconds. Females were found to have poor discriminant validity (AUC = 0.633), yet those with shoulder pain tended to fail in less than 47 seconds.

The final clinical assessment examined whether the PSET was more of a strength measure or an endurance measure. Isokinetic peak torque at 60˚/second in a horizontal shoulder abduction position was used as the criterion for strength. Isokinetic decay slope of 20 repetitions in a 60˚/second protocol of shoulder horizontal abduction was used as the criterion for endurance. Pearson Correlation between the time to failure of the PSET to the peak torque was r = 0.319, and between the PSET and decay slope was r = 0.054. These results support the PSET being more of a measure of strength than endurance. Based on secondary analysis, we speculate modifying the test based on bodyweight rather than standardized torque for the PSET.

Digital Object Identifier (DOI)

https://doi.org/10.13023/etd.2020.306

Funding Information

Evans N. Construct Validity of the Posterior Shoulder Endurance Test (PSET). Marshall University Research Committee. 2019 (Awarded $133.20)

Evans N, Konz S. A Reliability and Validity Study of the Posterior Shoulder Endurance Test (PSET). Marshall University Research Committee. 2017 (Awarded $250.00)

Available for download on Friday, July 22, 2022

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