Affiliations: [a] Sensory Motor Performance Program, Rehabilitation
Institute of Chicago, Chicago, IL, USA | [b] Department of Occupational Science and Technology,
University of Wisconsin-Milwaukee, Milwaukee, WI, USA | [c] Program in Physical Therapy, Department of
Kinesiology, University of Connecticut, Storrs, CT, USA | [d] Department of Medical Social Sciences, Feinberg School
of Medicine, Northwestern University, Chicago, IL, USA
Note: [] Address for correspondence: Ying-Chih Wang, OTR/L, PhD,
Department of Occupational Science and Technology, University of
Wisconsin-Milwaukee, Enderis Hall 971, 2400 S Hartford Avenue, Milwaukee, WI
53211, USA. Tel.: +1 414 229 1138; Fax: +1 414 229 5100; E-mail: wang52@uwm.edu
Abstract: Given the functional and epidemiological significance of lower
extremity strength, portable, low-cost measures of lower extremity strength
with robust psychometric properties are needed for clinical practice and
research. The purpose of this study was to compare measures of isometric knee
extension strength obtained with portable devices with criterion measures
obtained with a Biodex dynamometer. Sixty-eight healthy adults from Illinois
and Connecticut participated in this study. Each participant's isometric knee
extension strength was tested in random order using: 1) an integrated tension
load cell device (ITLCD), 2) a belt stabilized hand held dynamometer (BSHHD)
and 3) a Biodex System 3 isokinetic dynamometer. Equivalence of the 3 measures
was evaluated using repeated measures analysis of variance (ANOVA), Pearson
correlations (r), and intraclass correlation coefficients (ICCs). Results
supported good agreement between measures obtained with the ITLCD, BSHHD and
Biodex (r > 0.90, ICCs > 0.79). The ANOVA
results demonstrated that measures obtained with the ITLCD and the BSHHD did
not differ significantly. On average, the maximum isometric knee extension
torque was underestimated by 27 N-m and 32 N-m by the ITLCD and BSHHD,
respectively. Because The ITLCD was slightly better at approximating Biodex
torque scores and does not depend on skills of the examiner, the ITLCD was
recommended for inclusion in the motor battery of the NIH Toolbox.
