Figure 13.2 Transmissibility and gain as a function of frequency.

A number of different conditions were explored to establish the effect on the dynamic response of the standing subject (Pope et al., 1989b). In the erect posture, there was a single transmissibility peak at 5.5 Hz. The at-ease posture gave a slightly reduced peak, and a knee-bent posture attenuated the response. A pelvic tilt and Valsalva caused the peak to move to about 7 Hz while a tip toe stance moved the peak to 3 Hz. Standing on foam materials caused the peak to move to lower frequencies, while the wearing of different shoes did not significantly change the response.