Scientific/Clinical ArticleThe Concurrent Validity of a Hand-held versus a Stationary Dynamometer in Testing Isometric Shoulder Strength
Section snippets
Subjects
Thirty-eight men (n = 21) and women (n = 17), recruited through convenience sampling, voluntarily participated in the study. Eleven subjects were needed to have more than 80% power to detect a Pearson product coefficient of 0.70. With 38 subjects, the power was 99%. Inclusion criteria were 1) age 18 years and above; and 2) no wrist pain or pathology. Wrist pathology was an exclusion criterion due to the need for the shoulder strength to be transmitted by gripping the shoulder test device on the
Results
All patients completed the test protocol without difficulty. The mean isometric maximal strength obtained with the LIDO and the JTech for men and women and for subjects with or without shoulder symptoms are shown in Table 1. In all three muscle groups tested (flexors, abductors, and external rotators), men were stronger than the women (p < 0.001) with each dynamometer.
Correlations between the two dynamometer were high in all three shoulder muscle groups with Pearson coefficients (r) ranging from
Discussion
This study demonstrated a high correlation between scores obtained for isometric shoulder strength in men or women, with no or mild shoulder symptoms, using the LIDO SD and the JTech hand-held dynamometer. This is in agreement with the correlation established between static strength scores obtained with the HHD and SD when measuring strength of the knee24 and elbow.25 Correlations between scores obtained on a HHD and the LIDO during isometric elbow flexion and extension ranged from 0.72 to
Conclusion
The JTech computerized hand-held dynamometer provided isometric shoulder strength scores that are closely related to those obtained on the LIDO when testing shoulder abductors, flexors, and external rotators in the scapular plane. Both instruments can provide valid measures of isometric shoulder strength. Although scores between the instruments cannot be interchanged because of differences in units of measurements, determination of impairment levels should be related regardless of which
Quiz: Article # 138
Record your answers on the Return Answer Form found on the tear-out coupon at the back of this issue. There is only one best answer for each question.
- #1.
The purpose of the study was to test the
- a.
reliability of the JTech Power Track II in measuring shoulder strength
- b.
validity of the JTech Power Track II in measuring isotonic shoulder strength
- c.
validity of a hand held dynamometer in measuring isometric shoulder strength
- d.
specificity of the JTech Power Track II in measuring shoulder external rotation
- a.
- #2.
The
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2020, Journal of Shoulder and Elbow SurgeryCitation Excerpt :The handheld dynamometry measurements were obtained by multiple observers, increasing the likelihood of varying results. However, the reliability of handheld dynamometry has been tested and proved in both healthy and pathologic shoulders.1-3,5,6,16 Another limitation is that the control cohort did not match the experimental cohort in age.
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2019, Journal of Clinical Orthopaedics and TraumaCitation Excerpt :The MCID values for shoulder active forward flexion is 12°, active abduction is 7°, and active external rotation is 3°.16 Isometric muscle strength was assessed for shoulder flexors, abductors, and external and internal rotators using the JTech PowerTrack handheld dynamometer (JTech; JTech Medical, Salt Lake City, UT, USA), with known concurrent validity24 and reliability (ICCs 0.89–0.98).25 Shoulder muscle strength and ROM scores were compared to norms established in an age-matched controls and with similar testing procedures.26,27
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Funded by a New Investigator Award, Canadian Institute of Health Research. Joy C. MacDermid was funded by a New Investigator Award.