Laboratory evaluation of the complex interplay between whole-body vibration and spinal posture

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Whole-body vibration (WBV) affects heavy mobile machinery operators and is a significant health risk for 7% of the workforce. Vibration exposures vary between industrial environments, for example between mining and forestry environments. Industrial seats are one engineering control measure that can effectively reduce vibration exposures, but we have observed that individual seats are best-suited to attenuate WBV in specific vibration environments - they do not work optimally in all applications. I developed a seat selection algorithm for matching seats with vibration environments within my last Discovery Grant. However, the seats are merely one component of the complex workplace environment. Vehicle operators frequently adopt awkward postures, such as neck and trunk rotations, in order to gain the necessary field of view to safely operate the vehicle. Posture directly influences the transmission of vibrations through the body. For example, spinal posture influences the biodynamic responses such as apparent mass and the seat-to-head vibration transmissibility. The first short-term goal of this proposal is to evaluate the influence of body posture on their biodynamic response during realistic simulation of occupational tasks. The key aspects of this approach include performing this analysis under realistic simulations using our current virtual reality forklift simulator. The vibrations are produced using a robotic platform, the vehicle seating and controls match the industrial vehicle, the visual environment is simulated using virtual reality, and the workplace tasks are simulated using a gaming software engine. This project will focus on developing signal processing methods for windowing the biodynamic measures to specific postures, similar to Short Time Fourier Transforms for different categories of body posture. This approach will characterize elements such as the apparent softening with increasing excitation amplitude. The second objective of this proposal is to evaluate the influence of gender and anthropometrics on biodynamic responses during realistic simulation of occupational tasks. This is an important issue for two reasons: it directly relates to the long-term goal of this research program of understanding how vibration energy is transmitted and attenuated in humans, and it will identify the different potential risk factors that may affect the growing number of female workers in Canadian industry. The novelty of this proposal is combining the basic science approach to quantify biodynamic responses to whole-body vibration, and the influence of body posture, whilst performing these studies in a high-biofidelity virtual workplace environment. This is an important development with implications for both vehicle engineering and ergonomics, and may have broadly reaching implications for reducing the burden of whole body vibration injuries in Canadian industry.