Effectiveness and usability of a trunk posture feedback system: A longitudinal field study for up to six weeks in a distribution center.

Postural feedback systems are a potential ergonomic intervention to reduce postural exposures and mitigate musculoskeletal disorder risk, yet field-based evidence on their long-term effectiveness remains limited. We investigated a commercially available postural feedback system implemented in a logistics environment, which provided auditory and vibrotactile feedback in response to excessive trunk flexion. Thirty-two workers used the system for up to six weeks. No initial improvements in postural exposures were observed between baseline (Day 1, no feedback) and the first few days of feedback (Days 2-4). Mixed-effects models indicated no sustained improvements over time, with substantial variability across participants. Participants reported that the system was easy to use and increased postural awareness, although some noted inconsistencies in feedback. These findings suggest that more precise and context-aware feedback systems might better promote sustained behavioral change, though our results should be interpreted in the context of the specific system and work environment evaluated.