DSM - BIA
Before the development of the InBody Body composition analyzers measured a single impedance by attaching polar electrodes to the hands and feet (Whole Body Impedance). When body composition is analyzed using whole body impedance, the different metabolic characteristics of the trunk and limbs are not reflected in the results, and thus, an accurate body composition analysis cannot be achieved. InBody uses 8 polar tactile elctrodes where a different electrical voltage and current are sent through the inner body, resulting in 5 different impedances reading for the body's trunk and four limbs. This exclusive in-depth analysis of the InBody yields accurate results for total body composition, and is able to measure segmental muscle mass as well.
50kHz is the standard frequency used in BIA body composition analysis. This is because frequency of about 50kHz has the highest reactance, making it most convenient to see characteristics of the body, and also because it is easiest to use technically. However, a frequency of 50kHz cannot pass through the cell membrane, only through the extra cellular fluid, thus it is impossible to accurately measure intracellular fluid. In the late 1980's the argument that multifrequency should be utilized was proposed, and it was reported that a frequency over 200kHz was able to penetrate the cell membrane. Because InBody uses 6 frequencies of 1, 5, 50, 250, 500, and 1000kHz, it can accurately measure intracellular and extracellular fluid. The multifrequency technology of the InBody is difficult to implement and is the product of experienced research and understanding.