Whole-body vibration is a significant health risk for between 4% and 7% of the work force in North America. In addition, many factors compound the health risks of heavy machinery operators. For example, twisted trunk and neck postures stiffen the spine and increase the transmission of vibration to the head. Similarly, workers adopt awkward postures in order to gain appropriate lines of sight for machine operations. Although the relative contribution of these various issues can be evaluated in field studies and models, we propose that virtual reality is a powerful medium for investigating issues related to health and safety in mining machine operators. We have collected field data of posture and vibration, as well as visual environment, for a forklift operating in a warehouse. This paper describes the process and outcome of this field data collection, and provides a discussion on the next steps to develop and test the virtual reality model to enable laboratory testing. Our ongoing studies will evaluate the interplay between posture and vibration under conditions replicating routine heavy machinery operations, such as underground mining.

Background. Falls can be extremely detrimental to someone’s daily living, as well as life threatening This is especially true for individuals who have back problems, are sedentary, and have other health disorders. The purpose of this study was to investigate the effect of trunk extensor muscles fatigue on static postural control in young healthy adults compared to middle aged subjects. Methods. University students (n=10), and Middle-aged subjects (n=6; 40+ years of age) stood as immobile as possible on a force plate, with their feet together and eyes closed under two conditions; Fatigue and No fatigue. Fatigue was achieved through repetitive extensions of the trunk until a subjective fatigue level was reached. We measured center of pressure (CoP) displacements in the A/P and M/L planes using a force plate to assess standing balance. Findings. We did not observe any significant interaction between age and fatigue indicating that fatigue affected both age groups similarly. The CoP variability was higher for the middle aged compared to the young adults in both the fatigue and no-fatigue conditions. Interpretation. The results of this study indicate that trunk extensor fatigue does not affect balance differently for young compared to middle-aged subjects. This study also suggests that postural control decreases significantly with increasing age. Our finding that trunk extensor fatigue did not significantly affect the postural control of upright stance contradicts previous studies; this difference may be due to the subject sample in our study.