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.
