Previous research demonstrated that vertical whole-body vibration can induce feelings reminiscent of fatigue and lassitude. These studies used 4 Hz as the driving frequency as this has been shown to be prominent in road-induced vibration in heavy vehicles. A series of tests of cognition, brain function, heart rate and questionnaires concerning subjective effects were previously validated using 10 minutes of vibration at 4 Hz.
This report describes the use of these measures in a comparison between the effects caused by 4 Hz vibration and a vibration pattern recorded from a road in a small articulated truck.
Twenty-two young healthy participants were each exposed in separate experiments to 10 minutes of each vibration pattern. The results indicated that a road profile used to create a pattern of vertical vibration was as effective as 4 Hz in most respects.
There were minor differences from the previous study but these may have been due to the smaller numbers who participated in the current study. The equipment developed to obtain the road profile acceleration data proved to be very effective at obtaining a signal suitable for use in controlling the hydraulic actuator.
The differences in subjective and physiological responses to the two vibration profiles were minor, suggesting that 4 Hz may be a suitable substitute to ‘real’ road profiles in studying the effects of vertical vibration on fatigue.