BackgroundMyanmar migrant workers in Thailand's seafood processing industry develop work-related musculoskeletal disorders from tasks such as repetitive shrimp peeling and standing for extended periods. These workers remain largely unreached by standard health interventions due to language barriers and cultural isolation. Developing effective study for this vulnerable population requires meaningful involvement of workers in the study design process, recognizing their experiential expertise while acknowledging the distinct roles of researchers and community members. This paper documents how involvement with stakeholders such as migrant workers themselves shaped the co-design of a study testing a culturally appropriate digital health intervention for managing existing symptoms and preventing progression of musculoskeletal disorders.MethodsThis was a mixed-methods co-design study combining qualitative community engagement with quantitative expert validation. We conducted engagement sessions with 29 Myanmar migrant workers, organized into three groups by length of work experience (less than 2 years, 2-5 years, more than 5 years). We engaged 5 workplace stakeholders (human resource managers and production line supervisors) and consulted 4 international physical therapy experts for validation. Sessions were structured as conversations. Workers provided substantial input on intervention content, delivery methods, and practical requirements for the planned study. We accommodated their 12-hour work schedules, communicated in Myanmar language, and valued their experiential knowledge as essential for culturally appropriate study design. Thematic analysis identified key themes from worker input. Expert validators assessed the co-designed intervention using Content Validity Index (CVI) methodology.ResultsAll participating workers reported hand symptoms including numbness, tingling, and pain. Workers expressed preferences for health information through platforms they used daily, with Facebook emerging as the clear preference over text-based materials or in-person workshops on their only day off. These insights shaped the study intervention: a 4-week intervention with 12 progressive exercises addressing observed strain patterns: forward-leaning postures and repetitive hand movements. Workers specified practical requirements such as exercises must function in small dormitory spaces, outside work hours, without equipment. The peer challenge format emerged from their suggestions about sustained engagement. The co-designed study intervention achieved strong content validity scores from expert validators (I-CVI: 0.95-1.00; S-CVI/Ave: 0.94). The engagement process also highlighted ethical considerations when working with vulnerable migrant populations, including managing power differentials and protecting workers from potential workplace repercussions.ConclusionsWorkers possess essential knowledge about their needs and what works in their circumstances. We found that when research incorporates the input of the intended beneficiaries in study design, the result is a study intervention that is both clinically appropriate and practically usable. The co-designed intervention is now used for evaluation in the implementation research. This paper contributes a documented methodological approach to community involvement with a vulnerable migrant population, demonstrating that structured engagement can produce interventions meeting both worker feasibility requirements and clinical validity standards, while generating an honest account of the ethical tensions such work entails.