Quantitative Assessment of Trunk Flexion in Nurses Using Wearable Inertial Sensor: A Pilot Study

Nurses are at increased risk to develop musculoskeletal disorders (in particular low back pain) due to prolonged exposure to awkward postures, but there is a lack of quantitative objective measurements useful to characterize such postures. In the present study, we employed a single wearable inertial measurement unit (IMU) placed in the low back to monitor trunk flexion of eleven professional nurses working at maternity and cardiology wards during two hours of a regular shift. Trunk movement was analyzed using an exposure variation analysis approach which classifies flexion in three classes (i.e. 30–60°, 60–90° and >90°). The results show that tested nurses spent 3.5% of the monitored time with their trunk flexed between 30 and 60° and 0.2% between 60 and 90°. The IMU-based approach appears suitable to perform long-term monitoring of trunk postures in workers at risk for musculoskeletal disorders, overcoming the limitation of the observational methods and questionnaires.