Tung-Wu Lu, Horng-Chaung Hsu, Ling-Ying Chang, Hao-Ling Chen
DOI: 10.2340/16501977-0107

Objective: To develop and determine the reliability of a newly
-designed resistance-enhanced dynamometer for muscle strength measurement, and to test the hypothesis that enhancing the examiner’s resisting force improves the reliability of manual muscle strength measurements.
Design: An intra-examiner, inter-examiner, intra-session and inter-session reliability study.
Subjects: Twenty-five men (mean age 22. 5 (standard deviation (SD) 1. 7) years) were tested separately by 2 examiners using the resistance-enhanced dynamometer and a traditional hand-held dynamometer for an intra- and inter-examiner reliability study. Twenty-seven volunteers (mean age 22. 1 (SD 0. 8) years) were tested by a female examiner using the resistance-enhanced dynamometer for an intra- and inter-session reliability study.
Methods: Maximum resisting forces for the knee flexors and extensors were measured using the resistance-enhanced dynamometer and the traditional hand-held dynamometer.
Results: The traditional hand-held dynamometer had good intra-examiner reliability (intra-class correlation coefficient (ICC) = 0. 79–0. 93) but poor inter-examiner reliability (ICC = 0. 11–0. 28). The resistance-enhanced dynamo
meter had very good intra-examiner (ICC = 0. 91–0. 94), inter-examiner (ICC = 0. 98), intra-session (ICC = 0. 93–0. 99) and inter-session (ICC = 0. 91–0. 92) reliability. The resistance-enhanced dynamometer also had better inter-examiner agreement (smallest real difference (SRD) 9–16% for resistance-enhanced dynamometer, 21–43% for traditional hand-held dynamometer).
Conclusion: The resistance-enhanced dynamometer had very good reliability. Enhancing the examiner’s resisting force appeared to improve the reliability of manual muscle strength measurements. The resistance-enhanced dynamometer is useful for muscle strength measurements in clinical practice.