Resonance behavior of females and males exposed to whole-body vibration

The driving-point impedance and transmissibility resonance responses of females and males exposed to seated vertical vibrations were compared. Subjects were grouped according to weight percentiles. For all subjects, the frequency location of the peak responses occurred between 4 and 6 Hz, however, the magnitude of the impedance peak, normalized by dividing by the subject weight, was significantly lower for all females as compared to the males. No differences were observed between the weight percentile groups of the same sex. In general, the peak vertical chest transmissibility was higher and the peak horizontal transmissibility was lower in the smaller females as compared to the males. The chest transmissibility results alone do not provide definitive biodynamic data for improving vibration exposure standards and seat design criteria. Transmissibility data collected at other major anatomical regions and at a higher acceleration level are being evaluated to delineate those factors responsible for the observed differences in vibration response