Whole-body vibration perception thresholds of recumbent subjects - Part 2: Effect of vibration direction

This paper presents the results of laboratory experiment concerned with perception thresholds for whole-body vibration on recumbent subjects. Thresholds of subjects exposed to x-, y- and z-axis sinusoidal vibration were determined for supine, prone, lying on the left side and lying on the right side subjects (from 1 to 80 Hz). It was clear that the threshold curves, as a function of frequency, had different characteristics for vertical vibrations than for horizontal vibrations in the recumbent postures. Significant differences were found between perception thresholds for vertical vibrations and horizontal vibrations on recumbent subjects.