Workload, Exposure to Noise, and Risk of Musculoskeletal Disorders: A Case Study of Motor-Manual Tree Feeling and Processing in Poplar Clear Cuts

Abstract

Abstract:Motor-manual tree felling and processing (MMTFP) is among the most used options in timber harvesting operations and it is formally known to be a heavy job exposing the workers to safety hazards and harmful factors. Nevertheless, both workload and exposure depend on many operational, organizational, and worker-related parameters. Few studies have evaluated the ergonomics of such operations and fewer have been carried out using an integrated approach able to collect and interpret data for more than one ergonomic parameter. This study evaluated the ergonomic conditions of task-based MMTFP operations in flatland poplar forests by the means of workload, exposure to noise, and risk of musculoskeletal disorders. A fully-automatic approach was used to collect and pair the heart rate and noise exposure data that was complemented by video recording to collect postural data. Workload experienced by the worker was evaluated in terms of heart rate reserve (%HRR), indicating a heavy load during the productive time (%HRR = 46%); exposure to noise was calculated at the task and study level, exceeding (LAeq = 97.15 dB(A); L EX,8h = 96.18 dB(A)) the acceptable limits; and the risk of musculoskeletal disorders was evaluated using the concepts and procedures of the Ovako Working Posture Analysis System, indicating a high postural risk index (PRI = 275), which can cause musculoskeletal disorders (MSD). For more conclusive results, the research should be extended to cover the relevant variability factors.

Manual Cultivation Operations in Poplar Stands: A Characterization of Job Difficulty and Risks of Health Impairment

“…It is difficult to place the manual cultivation operations, in terms of difficulty and risks, amongst other forestry jobs, given the fact that heart response is dependent on many factors such as the age of subjects, gender and their operational environment. Nevertheless, in motor-manual felling, estimates from the same flat-land area and for a worker having an age close to the average of this study [17] were close to those found in this study. In steep terrain forests of Turkey, for instance, harvesting and forest nursery work was found to be difficult to moderate jobs with heart rate reserves of approximately 41 and 32%, respectively [39], while jobs such as cable work in steep terrain [40,41] and cable rigging [42] may take more effort.…”

“…Working predominantly with the back bent and twisted or bent forward and sideways (56.5% of the cases) may lead to health problems related to the lower back which is a known issue of forest operations jobs [14]. From this point of view, manual cultivation is a job that is even more hazardous compared to manual harvesting operations from Nordic countries [43] and close to that of motor-manual tree felling and processing operations from the area [17]. Compared to other kind of forestry-related partly mechanized jobs such as firewood processing [30] and wood debarking [44], manual cultivation seems to be riskier with the main problems coming from the back postures assumed during the work, since the arms and legs postures were found to be comfortable in most of the cases.…”

“…Polar ® V800 dataloggers (Polar, Kempele, Finland) including their H7 heart monitoring sensors mounted on straps were used to monitor the subjects’ cardiovascular activity during the undertaken tasks in terms of heart rate (HR, beats per minute). Procedures used to estimate the heart rate at rest (HRr, beats per minute), setup, collect, download and pre-process the data including that referring to location, were similar to those described in [17]. Data needed to evaluate the intensity of work (WI) was collected by the means of new, factory-calibrated, tri-axial accelerometers—Extech ® VB300 (Extech Instruments, FLIR Commercial Systems Inc., Nashua, NH, USA) attached to the pericardial strap of the heart rate datalogger.…”

“…Risks of musculoskeletal disorders (MSD) were evaluated for each subject, work day and location by the means of Ovako Working posture Analysis System (OWAS) as introduced by Karhu et al [26], then detailed e.g., [16] and discussed for its applicability in forest operations [7]. The choice of this postural analysis method was based on its history in use in forest operations [17,27,28] capability to analyze the whole body [26,29], simplicity in use [7,26], and possibility to compare the results e.g., [30] including comparisons to those coming from other industries. To this end, each video file collected in the field was broken in frames extracted at 1-s rate.…”

Occupational hazards in opinions of forestry employees in Poland

“…Apart from causing occupational disorders (occupational deafness), it may also be the cause of accidents. In addition, noise causes mental function disorders -hinders thinking processes, weakens concentration, and finally favours imprecise performance of activities [6,7,8,9].…”