Stadiometer Measurements of Driver'S Spinal Response to Steering Force and Vibration

Abstract

The effects on spinal loading of two aspects of the driving task - force exertion while steering and exposure to 4 Hz 1ms−2 peak vertical seat vibration - were investigated with a group of six male subjects seated in a driving simulator. In addition, the effect of the combination of the two aspects was tested. Spinal shrinkage was measured with a precision seated stadiometer over a 40 minute period. Analysis of variance showed that both steering actions and vibration had a significant effect on spinal loading (p<0.05 and p<0.025 respectively), even though the steering torque (5Nm) was moderate. The response was significantly greater in all three experimental conditions than in static sitting (in the same posture). There appeared to be a tendency for the mean spinal shrinkage to increase from 6.0 mm when steering to 7.1mm under vibration and 8.7mm when steering and vibration were combined, but the only difference which was statistical significant was that between the combined condition and steering alone (t test, p<0.01).