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Research article - Peer-reviewed, 2020

Seated postural loads caused by shock-type whole-body vibration when driving over obstacles

Stenlund, Tobias; Lundstrom, Ronnie; Lindroos, Ola; Rehn, Borje; Ohberg, Fredrik

Abstract

Operators of mobile machines within forestry work long hours in seated postures while being exposed to whole-body vibration (WBV) that is associated with pain in the lower back and neck. Still, little is known about the contribution from postural loads. In this study postural loads and shock-type WBV exposure on drivers operating a forwarder during terrain-like conditions was measured and quantified using inertial measurement units (IMUs). Five male drivers drove a forwarder repeatedly over standardized steel obstacles using a predefined speed and posture followed by driving over natural obstacles along a terrain course using a self-selected speed and posture. IMUs were affixed along the spine, on the back of the head of the driver and on the seat to detect orientation, velocity, and acceleration. The result shows that the methodology for measuring WBV and postural load with IMUs is feasible. Postural loads, expressed as range of motions (ROMs), when driving over a single standardized obstacle at a speed of 3.3 km/h were up to 21 degrees in the neck segments. Increasing vehicle speed and size of obstacles increased postural loads. The terrain course resulted in higher ROMs in all body segments compared to a standardized obstacle, a difference in sideway seat acceleration but no differences regarding angular velocities of the head. Mechanical shocks at the seat were prevalent but the action limit value was exceeded only for one driver. Postural loads remained small during all conditions indicating that the spine can remain stable during exposure to shock-type WBV of this nature.

Keywords

Mechanical Shock; inertial measurement units; posture; occupational health; forest machines; whole-body vibration

Published in

International Journal of Forest Engineering
2020, volume: 31, number: 3, pages: 184-191
Publisher: TAYLOR & FRANCIS INC

Authors' information

Stenlund, Tobias
Umea University
Lundstrom, Ronnie
Umea University
Swedish University of Agricultural Sciences, Department of Forest Biomaterials and Technology
Rehn, Borje
Umea University
Ohberg, Fredrik
Umea University

UKÄ Subject classification

Forest Science

Publication Identifiers

DOI: https://doi.org/10.1080/14942119.2020.1761745

URI (permanent link to this page)

https://res.slu.se/id/publ/109527