Multi-Frequency and Multi-Segment Body Impedance Spectroscopy in Sports and Rehabilitation Medicine with a new Wearable Device

  Body Impedance Spectroscopy (BIS) is a noninvasive fast method for assessing the composition of body districts. For these reasons BIS could provide important physiological or clinical information in sports medicine studies or in rehabilitation protocols. However, commercial  instruments are generally nonportable, limiting their use in sport applications. Wearable prototypes proposed in recent literature do not simultaneously satisfy the demanding needs of recording BIS in different segments at the same time, over a broad frequency range, for long periods and with high measurements rate, as sports medicine applications or exercise tests often requires.

 Therefore aim of this work is to present a new wearable prototype for monitoring multi-segment, multi-frequency BIS, unobtrusively over long periods, to be used in studies of rehabilitation- or sports- medicine.

  The system is designed to guarantee low weight, low power consumption and small size, consisting in an analog board with 2 current injecting electrodes and 4 electrodes sensing the voltage drops across 3 body segments; and in a digital board with a digital signal processor that generates square-wave current stimuli, digitalizes the sensed voltages and computes the electrical impedance at 10 frequencies from 1 to 796 kHz.

  The system performance is exemplified monitoring BIS in 3 body segments before, during and after physical exercise and a postural shift in a volunteer. The system was able to describe  exercise-induced changes in active and inactive muscular districts, their persistence during recovery and the effect of a sit-to-stand maneuver, demonstrating the information derivable from such class of BIS devices.