Ergonomic work analysis in the production of interiors for the transport industry

Abstract

Musculoskeletal disorders (MSDs) are the most frequent occupational health problem in the European Union where they have physical and economic consequences for workers, their families, companies, and the government. According to the European Agency for Safety and Health at Work (EU-OSHA), MSDs seem to be prevalent in construction, mining, and industry. These injuries are frequent in work situations where there is exposure to work activity risk factors, such as: standing posture for long periods of time, awkward joint postures (e.g., bending and twisting), repetitive movements, application of hand and finger force, exposure to vibrations and cold, manual handling of loads or no recovery periods between tasks. In this study, an Ergonomic Work Analysis (EWA) was carried out to understand the working conditions of workers at the MCG transportation factory unit, making part of metalworking industry, in Portugal. The objectives of the study were: the characterization of the metalworking industry regarding the risk of developing MSDs, the characterization of musculoskeletal symptoms self-reported by workers, the identification of the most problematic risk factors concerning each task assessed and, finally, the definition of an action plan to solve the identified problems. To characterize the tasks and workers, several methods/techniques were used, namely, free/systematized observations, non-structured interviews with workers, image/video recording and a questionnaire (adapted from the Nordic Musculoskeletal Questionnaire) specifically developed for this purpose. To assess and quantify the risk of developing MSDs, different methods, such as Rapid Entire Body Assessment (REBA), Rapid Upper-Limb Assessment (RULA), Revised NIOSH lifting equation, Revised Strain Index), ACGIH Hand Activity Level and the 2D Biomechanics, were used, to accommodate the specificities of each task. For data processing the SPSS© software was used and descriptive analyses were performed using measures of location and dispersion. The Chi-square test and Cramer’s V coefficient were used to assess associations between variables (demographic/work-related characteristics) and reported MSD symptoms. A significance level of 0.05 was adopted as a criterion to reject the null hypothesis. For the application of the above-mentioned methods the ErgoWeb EnterpriseTM software was used. All workers (N=18) agreed to participate in the study and the privacy of each participant was respected. Ten tasks were analyzed and assessed. Overall, the body regions with the highest percentage of complains were lower back (83,3%), neck (50%), upper limbs (hand/fist (50%) and shoulders (44,5%)). The results obtained corroborated data obtained from several studies. There was a positive association between work demands and complaints of pain in various body regions. Considering the postural assessment methods, all tasks presented a risk of developing musculoskeletal injuries (Risk level > 2). Through the application of the method of evaluating the physical demands associated with the tasks of manual handling of loads, it was verified that the weight of the loads is above the recommended, and therefore, the tasks presented a risk of developing injuries at the level of the lumbar spine (IL > 1). All these results show that investigations and measures to improve working conditions must be carried out.