Abstract
Due to the high cost of conducting field measurements, questionnaires are usually preferred for the assessment of physical workloads and musculoskeletal disorders (MSDs). This study compares the physical workloads of whole-body vibration (WBV) and awkward postures by direct field measurements and self-reported data of 45 occupational drivers. Manual materials handling (MMH) and MSDs were also investigated to analyse their effect on drivers' perception. Although the measured values for WBV exposure were very similarly distributed among the drivers, the subjects' perception differed significantly. Concerning posture, subjects seemed to estimate much better when the difference in exposure was significantly large. The percentage of measured awkward trunk and head inclination were significantly higher for WBV-overestimating subjects than non-overestimators; 77 and 80% vs. 36 and 33%. Health complaints in terms of thoracic spine, cervical spine and shoulder-arm were also significantly more reported by WBV-overestimating subjects (42, 67, 50% vs. 0, 25, 13%, respectively). Although more MMH was reported by WBV-overestimating subjects, there was no statistical significance in this study. PRACTITIONER SUMMARY: Self-reported exposures of occupational drivers are affected by many other cofactors, and this can result in misinterpretations. A comparison between field measurement and questionnaire was used to highlight the factors affecting the perception of drivers for whole-body vibration (WBV) exposure. Posture and musculoskeletal disorders influenced the perception of the similarly WBV-exposed drivers significantly.