Abstract
The purpose of this paper is to describe a portable belt-stabilized hand-held dynamometry (HHD) set-up for measuring knee extension force and to compare the magnitude and reliability of forces obtained with the set-up to those obtained without belt-stabilization. Measures for single-limb knee extension force were obtained via HHD from 16 young participants by 2 testers of substantially different strength. Measurements were obtained during 2 sessions 1 week apart. Testing was performed with participants in a bariatric chair – with and without HHD belt-stabilization. Data from the first session were used to compare the magnitude of knee extension forces. Data from both sessions were used to examine reliability via intraclass correlation coefficients (ICCs) and Bland-Altman plots. Forces measured with belt-stabilization were significantly (p< 0.001) higher than those measured without belt-stabilization. The differences were greater for male participants (p=0.006) and the female tester(p=0.001). Intertester reliability was poor for measurements obtained without belt-stabilization (ICC=0.17) but good for measurements obtained with belt-stabilization (ICC=0.84). Differences between testers increased with the magnitude of force measured when no belt-stabilization was provided but not when belt-stabilization was used. Test-retest reliability was good when belt-stabilization was employed (ICC=0.87 and 0.92). When belt-stabilization was not used, the test-retest reliability was acceptable for the male tester (ICC=0.77) but not the female tester (ICC=0.50). In conclusion, the set-up examined is affordable, portable and easy to assemble. It allows for rapid testing of knee extension strength. With HHD belt-stabilization, the set-up can be recommended for clinicians and researchers requiring objective measures of knee extension strength in diverse settings.