AUTHOR=Allione Federico , Lazzaroni Maria , Gkikakis Antonios E. , Di Natali Christian , Monica Luigi , Caldwell Darwin G. , Ortiz Jesús TITLE=FleXo: a flexible passive exoskeleton optimized for reducing lower back strain in manual handling tasks JOURNAL=Frontiers in Robotics and AI VOLUME=Volume 12 - 2025 YEAR=2025 URL=https://www.frontiersin.org/journals/robotics-and-ai/articles/10.3389/frobt.2025.1687825 DOI=10.3389/frobt.2025.1687825 ISSN=2296-9144 ABSTRACT=Musculoskeletal disorders, particularly low back pain, are some of the most common occupational health issues globally, causing significant personal suffering and economic burdens. Workers performing repetitive manual material handling tasks are especially at risk. FleXo, a lightweight (1.35 kg), flexible, ergonomic, and passive back-support exoskeleton is intended to reduce lower back strain during lifting tasks while allowing full freedom of movement for activities like walking, sitting, or side bending. FleXo’s design results from an advanced multi-objective design optimization approach that balances functionality and user comfort. In this work, validated through user feedback in a series of relevant repetitive tasks, it is demonstrated that FleXo can reduce the perceived physical effort during lifting tasks, enhance user satisfaction, improve employee wellbeing, promote workplace safety, decrease injuries, and lower the costs (both to society and companies) associated with lower back pain and injury.