Assessment of ergonomic risk in industrial field: Analysis of the operators’ body postures through wearable sensors

Work-related musculoskeletal disorders (WMSDs) are currently among the most widespread pathologies which affect workers in several occupational fields. Non-neutral postures, especially when maintained for prolonged periods of time, represent a relevant risk factor for WSMDs and thus, the correct assessment of worker’s exposure is a crucial issue in order to prevent, or at least reduce, their onset. Qualitative methods (i.e. direct observation, questionnaires) are the most widespread techniques to characterize posture under actual working conditions, but they provide limited information and are time-consuming. The present study aimed to propose an ecological method to assess as non-neutral trunk posture under actual working conditions. A single miniaturized wearable inertial sensor located in the low-back has been employed to evaluate trunk flexion features in two workers engaged in manual material handling tasks, during 4 hours of a regular work shift. Data collected were processed following an exposure variation analysis (EVA) in order to evaluate intensity, frequency and duration of the exposure. An ergonomic risk level was then associated following the National Institute for Occupational Safety and Health guidelines (NIOSH, 2014). The obtained results suggest that the proposed approach is suitable to support the identification of potentially harmful strategies adopted by the workers or may help to recognize the necessity to reorganize the workstations to improve the working conditions.