title: Factors influencing accuracy and reproducibility of body resistance measurements by foot-to-foot impedancemeters.
abstract: The electronics of a BodySignal V2 (Tefal, France) foot-to-foot impedancemeter (FFI) was modified to display the foot-to-foot resistance instead of body fat. This device was connected to electrodes of different sizes mounted on a podoscope permitting photographs of subjects feet soles and electrodes in order to calculate the contact area between feet and electrodes. The foot-to-foot resistance was found to decrease when the contact area of feet with current and voltage electrodes increased. It was also sensitive to feet displacement and a backward move of 5 cm increased the mean resistance by 37 Ω. The resistance reproducibility was tested by asking the subject to repeat measurements 10-times by stepping up and down from the podoscope. The mean SD of these tests was 0.88% of mean resistance, but it fell to 0.47% when feet position was guided and to 0.29% with transverse voltage electrodes. For good reproducibility, it is important that voltage electrodes be small and that the scale design facilitates a correct position of heels on these electrodes.
authors.affiliation: UMR CNRS 7338, Department of Biological Engineering, Technological University of Compiegne , BP 20529, 60205 Compiegne , France.
authors.forename: Sana
authors.initials: S
authors.lastname: Bousbiat
authors.forename: Michel
authors.initials: M
authors.lastname: Jaffrin
authors.forename: Imen
authors.initials: I
authors.lastname: Assadi
mesh_terms: D000328:Adult; D001698:Biomedical Engineering / Q000295:instrumentation / Q000379:methods; D017097:Electric Impedance; D004566:Electrodes; D005260:Female; D005528:Foot / Q000502:physiology*; D006801:Humans; D008297:Male; D015203:Reproducibility of Results
keywords: Foot-to-foot impedancemeters; optimization of plantar electrodes; reproducibility and accuracy of body resistance measurements