A comparison between impedance measured by a commercial analyzer and your value adjusted by a theoretical model in body composition evaluation

The use of an electrical current for the evaluation of several physiological variables in the human body is not a recent technique but continues to awaken great interest in the research community. One of the greatest applications for such a technique is the study of body composition through bioimpedance, where generally a equipment with a tetrapolar array set of electrodes is used to realize the bioimpedance measurement. The aim of the present work is to show that the bioimpedance measured is normally sub-estimated and to develop a correction factor for such values. The comparison between the original bioimpedance values, obtained by commercial equipment, and their corrected values, in body composition evaluation, will be shown. Body composition tests were conducted on 10 male subjects. Besides the bioimpedance analysis, anthropometric measures consisting of height, weight and skinfold-thickness were also obtained from the subjects to allow an estimation of the body composition by anthropometric equations established in the literature. The comparison results point to a better correlation (Pearson coefficient, r = 0.9735) between the anthropometric estimated fat-free mass (FFM) and the estimated value by the corrected bioimpedance adjusted, when compared with the original ones Pearson coefficient, r = 0.9487.