Whole-Body Vibration exposure. An ergonomic evaluation of the effects of an active suspended cab fitted on an agricultural telehandler.

Exposure to whole body vibration (WBV) is one of the most important risk factors for musculoskeletal disorders (MSDs). Agricultural machinery operators are particularly at risk and it is therefore important to minimize the transmission of harmful vibrations to the driver as much as possible. Telescopic handlers are self-propelled vehicles very versatile used on different terrains and for different operations. Despite their diffusion few studies investigated their vibrational safety and comfort. The objective of the study was to investigate whether an active cab suspension system fitted on a telehandler was effective in reducing WBV and in improving comfort. Sixteen male healthy professional operators drove a telehandler on a 100 m ISO 5008 smooth track at two different speeds (5 and 12 kph) with activated and deactivated cab suspension system. Adopting an ergonomic approach, different aspects of the human-machine interaction were analyzed: 1) WBV measurements, 2) subjective ratings of general comfort and local body discomfort, and 3) anthropometric characteristics of the users. The suspension system was effective in reducing WBV and in improving comfort, especially for individuals with higher stature, body mass and Body Mass Index (BMI). Some neck/shoulder and lumbar complaints seems to remain, even when the system was activated. Results suggest that the operators, given their wide range of physical variability, may need more adjustable or customizable WBV reduction systems.