Ergonomic evaluation of work related musculoskeletal disorders in informal work: a study on fish vendors in Ampara, Sri Lanka

Introduction: Fish vending, an informal work, is expected to cause WMSDs due to prolonged standing, shoulder elevation, bending and twisting, repetitiveness and high physical activities. The study was carried out to investigate the prevalence of WMSDs and the associated factors among fish vendors. Methods: In a cross sectional study, 202 fish vendors were selected using simple random sampling technique with face to face interview to solicit data on working conditions and WMSDs in the coastal areas of the Ampara district during June to August 2022. Fish vendors were video recorded for postural analysis using RULA. Results: The WMSDs among fish vendors in neck, shoulder, upper back, lower back, elbow wrist, hip, knee and feet were 52%, 55%, 53.3%, 49.1%, 52%, 65.3%, 56%, 57.4% and 46% respectively. The final RULA score of 7 was obtained for 56% of fish vendors. The awkward working posture was significantly associated with WMSD in wrist while heavy lifting was associated with WMSDs in neck. The humidity was significantly associated with WMSDs in shoulder, lower back and knees and thermal comfort was significantly associated with WMSDs in lower back and knees. The age and experience significantly associated with WMSDs in all the body regions investigated. Conclusion: The majority of fish vendors had WMSDs in different body regions. The awkward posture, heavy lifting, age, experience, humidity and thermal comfort were associated with WMSDS. Fish vendors are required to use a recommended size of boxes to lift and carry fish and to have correct standing work surface height and also to use knife designed with proper weight, handle size and shape.