Objectives Musculoskeletal disorders (MSD) are main cause of work absence, reducing sustainability of working trajectories. The objective of INTEVAL_Spain project is to assess the effectiveness of a multifactorial intervention at the workplace to prevent MSD.

Methods The intervention comprises evidence-based primary (participatory ergonomics-PE), secondary and tertiary prevention (case management-CM), and health promotion targeted to MSD. All components are integrated and require full coordination. A cluster randomized trial with a late intervention control group is being implemented to evaluate its effectiveness. Quantitative and qualitative information is being obtained from databases of participating companies, questionnaires, pre-post learning tests, satisfaction surveys, project records and focus groups.

Results Eight clusters of nurses and aides (n=473) employed at two hospitals were selected and randomly distributed into intervention (n=4) and control (n=4). A prevalence of 80% of back and/or neck pain and 70% of high physical demands at baseline were observed. A champion was recruited, together with 8 managers, 33 referent workers and 3 workers' representatives who volunteered to be clusters leaders. A total of 105 proposals for ergonomic improvements are being managed by operational groups. CM is based on the Scottish EASY model, and five main services are offered, combined with health promotion activities: rehabilitation, MSD health beliefs counseling, targeted cognitive behavioral therapy, Nordic walking, Mediterranean diet, emotional training and mindfulness.

Conclusions The intervention is being implemented with high levels of participation and acceptance. If it proves to be cost-effective, it will provide updated, relevant and innovative evidence for MSD preventive strategies at the workplace.