Shoulder
Measuring shoulder external and internal rotation strength and range of motion: comprehensive intra-rater and inter-rater reliability study of several testing protocols

https://doi.org/10.1016/j.jse.2014.01.006Get rights and content

Background

Shoulder range of motion (ROM) and strength measurements are imperative in the clinical assessment of the patient's status and progression over time. The method and type of assessment varies among clinicians and institutions. No comprehensive study to date has examined the reliability of a variety of procedures based on different testing equipment and specific patient or shoulder position. The purpose of this study was to establish absolute and relative reliability for several procedures measuring the rotational shoulder ROM and strength into internal (IR) and external (ER) rotation strength.

Methods

Thirty healthy individuals (15 male, 15 female), with a mean age of 22.1 ± 1.4 years, were examined by 2 examiners who measured ROM with a goniometer and inclinometer and isometric strength with a hand-held dynamometer (HHD) in different patient and shoulder positions. Relative reliability was determined by intraclass correlation coefficients (ICC). Absolute reliability was quantified by standard error of measurement (SEM) and minimal detectable change (MDC). Systematic differences across trials or between testers, as well as differences among similar measurements under different testing circumstances, were analyzed with dependent t tests or repeated-measures analysis of variance in case of 2 or more than 2 conditions, respectively.

Results

Reliability was good to excellent for IR and ER ROM and isometric strength measurements, regardless of patient or shoulder position or equipment used (ICC, 0.85-0.99). For some of the measurements, systematic differences were found across trials or between testers. The patient's position and the equipment used resulted in different outcome measures.

Conclusions

All procedures examined showed acceptable reliability for clinical use. However, patient position and equipment might influence the results.

Section snippets

Participants

A convenient sample of 30 asymptomatic adults (15 women and 15 men) was recruited for this investigation from a local university setting during a 7-month interval. Estimated sample size was based on literature5 suggesting that with 2 raters, a significance level of 0.05 and a power of 80% to determine an ICC score of 0.7, that a minimum of 19 samples would be required. The mean (standard deviation) for the participants' age, body weight, and height were 22.1 (1.4) years, 76.8 (17.8) kg, and

Results

Data from the reliability analysis for ROM measurements are summarized in supplementary Table I (available on the journal's website at www.jshoulderelbow.org). ICCs for intra-rater reliability varied from 0.85 (IR in 90° forward flexion/goniometer/supine) to 0.99 (IR in 90° abduction/inclinometer/sitting) and for interrater reliability from 0.96 (IR in 90° forward flexion/sitting/inclinometer) to 0.99 (IR in 90° abduction/sitting/inclinometer), showing excellent intra-rater and inter-rater

Discussion

This study established good to excellent reliability for IR and ER passive ROM measured with a goniometer or an inclinometer and isometric strength measurements using a HHD, regardless of the patient's position, shoulder position, or equipment used. This is, to our knowledge, the first study to provide a comprehensive reliability analysis of ROM and strength measurements performed by the same examiners and combining several procedures frequently used in clinical practice.

Conclusions

The purpose of this study was to establish absolute and relative reliability for several procedures measuring the rotational shoulder ROM and strength into IR and ER. The study results show good to excellent reliability values for all procedures performed. Clinicians should consider their choice based on the available equipment and the ability of the patient to achieve the body or shoulder position. In general, measurements in the supine position are recommended because of practical

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    The Gent University Ethics Committee approved this study (Approval No. B67020109775).

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