Upper limb posture and movement during tracked versus wheeled harvester operation on Pinus thinning

Abstract

ABSTRACT Timber harvest operations in a Pinus taeda thinning require a few different postures by machine operators that could be harmful to their health. This research aimed to analyze the upper limb posture of the operators in two harvester models, a tracked versus wheeled harvester in thinning of Pinus taeda stands, to identify possible issues and propose ergonomic solutions. The postural analysis was conducted in thinning operations, by filming the operators at their workstations. Posture evaluations were performed by the Rapid Upper-Limb Assessment (RULA) and Rapid Entire Body Assessment (REBA) methods and analyzed the outcomes by factorial analysis. Results showed that the operators stayed for a long time in the static sitting posture and with operational repetitive movements, worsened by the absence of recovery work breaks, with significant statistical differences for the two machines evaluated. For the tracked harvester, 15 typical postures were identified, and in 91% and 92% of the workday, the operator had their trunk and head inclined, respectively. For the wheeled harvester, only eight typical postures were identified, and in 12% and 50% of the time, the operatorremained with their trunk and head tilted. Finally, we were able to observe that tracked harvester operators spent more time on postures ergonomically harmful, with higher action level measures needed. The wheeled harvester provided the best working conditions in terms of posture and repetitiveness, making it the most ergonomically suitable machine.