Method Research Of Body Composition(fat)measurement With Bioelectrical Impedance Analysis

This article's purpose was to search the more accurate method of body's composition measurement with Bioelectrical impedance technique. The article discussed the limitations of the whole body tetrapolar method and the seientificity of the hypothesis of segmental six-electrode method and the accuracy of the method. The segmental six-electrode method was used to design instrument, and to compare with the instrument which was used the whole body tetrapolar method, and to illuminate the scientificity and the accuracy of the segmental six-electrode method. The article used the segmental six-electrode method to design instrument for body fat measurement. The instrument processed one frequency, was controlled with computer, used electrode for long using. The instrument could measure body's segmental impedances and reactances. The measurement range of impedance was 10 to 600Ω. The accuracy of measurement was ±1%. The measurement range of reactance was 1 to 50Ω. The accuracy of measurement was ±1%. The interface of software was object oriented. And the software have the function of data-base management. Electrode for long using make the instrument low consume and without pollution, so it fit the need of the community and the family. We designed the standard system of body fat measurement (underwater weighing system), with the body density method. The system was not according to the underwater weighing method to measure body volume ,but the archimedes'law. The greatest virtue of the system was low cost, and didn't bring more operational difficulty, and the accuracy was low to 100 milliliter which satisfied the need of measurement. The comparing experiment among the new body fat measurement instrument, the underwater weighing system and the body fat measurement instrument (made by Omron corporation, HBF-301 ) was processed. The result showed that the correlation between the new instrument and the underwater weighing system was 0.950, the standard error of estimate was 1.84Kg; and the correlation between the Omron instrument and the underwater weighing system was 0.708, the standard error of estimate was 3.12Kg. Thus illuminated that the segmental six-electrode method was better than the whole body tetrapolar method.