Obesity effects on muscular activity during lifting and lowering tasks.

Obesity is an emerging health problem and its incidence has been increasing throughout the workforce. In industrial workstations, vertical handling tasks (VHT), including lifting and lowering, are very common and can cause a significant muscular overload for the involved workers. During these tasks, muscular activity may be considerably affected by workers' body conditions. This study aims to analyze and compare the muscular activity in subjects with different obesity levels, using surface electromyography (EMG), during predefined VHT. Six different VHT (combining 5, 10 and 15-kg loads with two task styles) were performed. EMG data normalization was based on the percentage of maximum contraction during each task (MCT%). The results show that obesity influences the MCT%, which in turn increases the muscular effort during VHT. The current investigation demonstrates that obesity is a relevant musculoskeletal risk factor regarding VHT. The engineering analysis and design implications of this work can thus be perceived.

Ergonomic intervention on a packing workstation with robotic aid -case study at a furniture manufacturing industry.

BACKGROUND: Several risk factors among packing lines workers can lead to Work-related Musculoskeletal Disorders (WRMSD) occurrence. Foreseeing WRMSD prevention and productivity increase, some furniture manufacturing industries have been investing in the adoption of robotic solutions. In this field, ergonomics plays an important role to verify if automation implementation has been successful. OBJECTIVE: This study aims to address the general impact and effectiveness from an ergonomics point of view of the implementation of a robotic aid in a packing workstation. METHODS: The Nordic Musculoskeletal Questionnaire (NMQ) was applied to 14 workers of semi-automated packing lines. Some additional questions about occupational conditions were included. In order to assess the ergonomic impact of the robotic aid, Rapid Upper Limb Assessment (RULA) was also applied by trained ergonomists, by analyzing the considered packing workstations before and after the adoption of the robotic aid proposed solution. RESULTS: The results showed that trunk torsion was the most highlighted WRMSD risk factor by all workers, associating it with the lumbar pain. The obtained RULA scores demonstrated that the adoption of a robotic aid eliminated this risk factor and, consequently, reduced the corresponding WRMSD risk. CONCLUSIONS: The adoption of robotic aids can be instrumental in reducing WRMSD risk in furniture manufacturing industries. Ergonomic studies with workers' participatory approaches seem to be an appropriate strategy to enable the validation and development of industrial robotic solutions.

Effects of workers' Body Mass Index and task conditions on exertion psychophysics during Vertical Handling Tasks.

BACKGROUND: Obesity prevalence in the workforce is clearly increasing. Simultaneously, manual lifting/lowering loads, referred to as Vertical Handling Tasks (VHT) in this paper, are common in industries and services. Performing VHT exposes workers to physical overload, which can be measured using a psychophysical approach. Various risk factors can increase this overload, including individual factors such as workers' Body Mass Index (BMI). OBJECTIVE: To study the possible effects of workers' BMI and some task conditions on physical overload during VHT. METHODS: Psychophysical data were collected from 51 participants having different body constitutions (including non-obese, overweight and obese). The participants performed 6 VHT (3 different loads ×2 workstation configurations), during which they lifted and lowered a test-box between their knees and shoulders. For each task, they reported their perceived exertion using the Borg Category Ratio-10 (CR-10) scale. RESULTS: The results showed that the CR-10 scale is sensitive to the variation of the task conditions tested. However, the psychophysical data pointed to a tendency to decrease the perception of physical overload as workers' BMI increases. CONCLUSIONS: This may compromise the validity of the application of psychophysical data as an ergonomic approach for Work-Related Musculoskeletal Disorders (WRMSD) prevention in obese workers.

Manual materials handling: knowledge and practices among Portuguese health and safety practitioners.

OBJECTIVE: There are several methodologies to assess the risk involved in Manual Materials Handling (MMH). The aim of this study was to identify the knowledge and use of risk assessment methods among Portuguese Health and Safety (H&S) practitioners. PARTICIPANTS: The study involved the participation of 331 H&S practitioners and other related prevention professionals. METHOD: An e-mail invitation to complete an online survey was sent to all Portuguese registered H&S practitioners. The previously developed and validated questionnaire included three different sections: (1) company characteristics; (2) description of types of MMH tasks performed; and (3) the respondents' use of and knowledge about risk assessment methods for MMH tasks. RESULTS: The answers obtained were collected from almost 350 companies. The characteristics of the companies showed that there is a predominance of external and internal H&S services for Small and Medium sized Enterprises (SMEs) and large companies, respectively. The NIOSH equation, Key Indicator Method (KIM) and Manual Assessment Chart (MAC) were identified as the most used and recognised risk assessment methods. CONCLUSION: Questionnaire results show that an important number of Portuguese H&S practitioners recognise some methods but have difficulty applying them correctly. Some practitioners reported that they had never used any type of risk assessment method.