POSTURAL SWAY IN OFFICE WORKERS: A REAL-TIME INERTIAL SENSOR-BASED ANALYSIS OF MOVEMENT VARIABILITY IN CHRONIC SPINAL PAIN AND PAIN-FREE ADULTS

Abstract

Sitting is a dominant postural behavior in modern office work, with a substantial proportion of the working day spent seated. Although functionally necessary, prolonged sitting has been associated with an increased risk of chronic musculoskeletal disorders, particularly chronic spinal pain. Characterizing seated postural control may help physiotherapists better understand chronic spinal pain and support the development of preventive and therapeutic interventions. This thesis investigated trunk motor variability during seated work in office workers with and without chronic spinal pain. Postural sway was used as an indicator of postural control and trunk motor adaptation and was quantified using wearable inertial sensors in real-world occupational settings. Trunk movement time series were analyzed using both linear and nonlinear methods, while spinal pain characteristics were assessed using validated self-report questionnaires. The research comprised complementary studies, including a narrative review of movement variability analysis methods, a week-long multimodal data acquisition protocol integrating trunk kinematics and self-reported outcomes in Portuguese Tax Authority workers, and a cross-sectional field study examining real-world trunk postural sway. Comparisons between workers with and without chronic spinal pain and correlational analyses within the pain group were performed. Workers with chronic spinal pain often have alterations in postural sway behavior compared to pain-free workers, reflected in changes in movement variability and postural stability. Higher pain intensity tended to be associated with reduced trunk motor variability, suggesting a more constrained postural control strategy. Temporal analyses indicated that trunk sway patterns varied dynamically across the workday. These studies provide preliminary evidence that postural sway may be altered in office workers with chronic spinal pain.