Biospace InBody720, Руководство пользователя, Страница: 80 / 84

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1. More about the InBody720
A. More About InBody720
The Bioelectrical Impedance Analysis (BIA) method is based on the fact that the human body consists of conductors and
non-conductors.
Generally 50~70% of the human body consists of water which functions as a conductor, whereas body fat functions as a
non-conductor.
The classic BIA method measures the impedance of the whole body on the assumption that the human body can be
considered a cylinder for application of this model. If A is the cross sectional area, and L is the length, the impedance of
the cylinder can be expressed as follows.
If both sides are multiplied by L, We get the new expression as follows.
According to this expression, if we know the L and the impedance value, we get the
volume. That is to say, if we know the height of the human body (acting as a conductor), and know the impedance value,
we can get the volume of body water. Here, the volume represents examinee’s height. Therefore, the two directly used
variables in body composition analysis are impedance and height.
The principle of the InBody720’s body composition analysis is explained by the following; the volume of body water, an
electrolyte, is calculated first with a measured impedance value. Then, we can get the value of fat free mass using the
volume of body water. Body fat mass is determined by deducting the lean body mass from the measured weight.
Height should be entered by the user. Weight can be directly measured on the InBody720.