Vertical-dominant and multi-axial vibration associated with heavy vehicle operation: Effects on dynamic postural control.

Heavy vehicle operators suffer from increased fall risk, potentially due to exposure to whole-body vibration (WBV) that compromises postural control. This study aimed to characterize the relative impacts of multi-axial WBV vs. vertical-dominant WBV on dynamic postural control during sit-to-stand transition and stair descent, following prolonged vibration exposures. We also compared the effectiveness of a standard (single-axial passive suspension) seat with a multi-axial active suspension seat intervention. Vertical-dominant WBV adversely affected dynamic postural control. However, multi-axial WBV had no added adverse effects on postural control compared to vertical-dominant WBV. The multi-axial active suspension system did not outperform the standard seat in mitigating vibration effects on postural control during exposures but led to faster recovery during breaks between exposures. Overall, our results confirmed the negative effects of WBV on dynamic postural control but did not detect any additional negative effects associated with multi-axial WBV when compared to vertical-dominant WBV.