Vibration transmissibility and apparent mass changes from vertical whole-body vibration exposure during stationary and propelled walking

Abstract

Whole-Body Vibration (WBV) is an occupational hazard affecting employees working with transportation, construction or heavy machinery. To minimize vibration-induced pathologies, ISO identified WBV exposure limits based on vibration transmissibility and apparent mass studies. The ISO guidelines do not account for variations in posture or movement. In our study, we measured the transmissibility and apparent mass at the mouth, lower back, and leg of participants during stationary and propelled walking. Stationary walking transmissibility was significantly higher at the lumbar spine and bite bar at 5 and 10 Hz compared to all higher frequencies while the distal tibia was lower at 5 Hz compared to 10 and 15 Hz. Propelled walking transmissibility was significantly higher at the bite bar and knee at 2 Hz than all higher frequencies. These results vary from previously published transmissibility values for static participants, showing that ISO standards should be adjusted for active workers.

Vibration Transmission during Manual Wheelchair Propulsion: A Systematic Review

“…Nevertheless, this standard is not the best framework to investigate MWC users' exposition to vibration. Some studies underlined the limits of using a standard developed for non-voluntary motions on MWC users propelling an MWC, since the voluntary motion was shown to affect the vibration transmissions through the body [22,77]. The use of the ISO 2631 standard is even more inappropriate as no article complied with all of its recommendations.…”

“…However, as for the other models, the whole MWC was constructed as a single rigid body, thus preventing modification of the MWC properties and settings. Moreover, no model was developed for the MWC during the propelling action, whereas the vibrating properties of the MWC could be different between users between dynamic and resting conditions [22]. Therefore, no model currently exists for estimating vibration transmissibility during MWC propulsion.…”

“…To reduce vibration exposure, for example, protection equipment can be set up, or a decrease of the daily exposure time may be planned. However, VDV and w-RMS parameters do not consider the interaction with the human body (i.e., effect of the muscular control, or tissue properties) [22][23][24]. Consequently, other parameters, such as transmissibility, have also been proposed in the literature.…”

“…In addition to these guidelines, various mathematical models of the human body were developed to predict the amount of vibration and identify parameters that could decrease vibration exposure. Among the different models, the models based upon lumped parameters are the most common for predicting WBV transmission [22]. These models are based on the transfer function between different points of the human body and are composed of mass, springs, and dampers.…”

Spatiotemporal gait parameter changes due to exposure to vertical whole-body vibration

“…As the biodynamic responses of exposure to vWBV on static subjects were becoming clearer, studies also began emerging regarding the effects of vWBV on dynamic subjects. Chadefaux et al [11] recently found that the TM of a walking subjects decreases with greater distance from the driving point and that the AM response was between that of a standing subject in the neutral posture and a standing subject with bent knees.…”