The Concurrent Validity of a Hand-held versus a Stationary Dynamometer in Testing Isometric Shoulder Strength
published online 29 June 2009.
Abstract
Study design
Clinical Measurement-Validity.
Introduction
Validity of the JTech PowerTrack II hand-held dynamometer (JTech; JTech Medical, Salt Lake City, UT) for measuring shoulder strength has yet to be established.
Purpose of the Study
To examine the concurrent validity of isometric strength scores obtained with the JTech PowerTrack II, and on a stationary dynamometer, the LIDO WorkSET (LIDO; LoredanBiomedical, West Sacramento, CA).
Methods
Thirty-eight subjects performed three maximal efforts of shoulder flexion, abduction, and external rotation on a single occasion on the two dynamometers. Two testers were randomly assigned to administer the tests.
Results
Pearson correlations between the scores on the two dynamometers (r.0.81) indicated a good concurrent validity. Correlations were similar when the results were subdivided by tester or gender.
Conclusions
This study suggests that either the JTech PowerTrack II or LIDOWorkSET provide comparable scores for shoulder strength. Although not interchangeable because of the differences in units of measurement, the relative conclusions about strength should be similar, regardless of which instrument is used.
Level of Evidence
Not applicable.
School of Rehabilitation Sciences, McMaster University, Hamilton, Ontario, Canada
School of Rehabilitation Sciences, McMaster University, Hamilton, Ontario, Canada
Hand and Upper Limb Centre, St. Joseph's Health Centre, London, Ontario, Canada
School of Rehabilitation Sciences, University of Western Ontario, London, Canada
Hand and Upper Limb Centre, St. Joseph's Health Centre, London, Ontario, Canada
Correspondence and reprint requests to Jean-Sébastien Roy, PT, PhD, School of Rehabilitation Science, McMaster University, IAHS, 1400 Main Street West, Hamilton, Ontario L8S 1C7, Canada
∗ Funded by a New Investigator Award, Canadian Institute of Health Research. Joy C. MacDermid was funded by a New Investigator Award.
ABSTRACT