The Influence of Body Mass on Whole-Body Vibration: A Quad-Bike Field Study

Objectives: The aim of this field study was to explore the relationship between body mass and quad bike induced whole-body vibration (WBV) exposure in a group of New Zealand rural workers. Methods: WBV exposure was recorded using a seat pad mounted tri-axial accelerometer while rural workers (n=34) were driving a quad bike for approximately half an hour on a pre-marked track on farm terrain. Personal factors such as age, height and quad bike driving experience were also surveyed and included as co-variates. Vibration dose value (VDV) was calculated by analyzing the recorded raw vibration data samples (n=34) using vibration analysis software and corrected to a one hour equivalent exposure for further statistical analysis. To evaluate for the relationship between variables of interest (body mass, height, age and driving experience) and one hour VDVZ (1hrVDVZ), univariate and multivariate linear regression analysis were conducted. Results: Mean 1hrVDVZ was 13.2 m/s 1.75 exceeded the VDV exposure action value of 9.1 m/s 1.75 . Univariate analysis demonstrated body mass (R 2 = 0.340) significantly (p < 0.0003) associated with 1hrVDVZ while age, body height and quad bike driving experience were not. In a multivariate backward linear analysis body mass, height, and experience combined to explain 38% (R 2 = 0.376) of the variance in 1hr VDVZ, however, only body mass (p= 0.0004) demonstrated statistical significance. Conclusion: Body mass is significantly and negatively associated with quad bike induced WBV (1hrVDVZ) in a group of New Zealand rural workers.