Multimethod ergonomic assessment of waste-picking work using a human-powered vehicle in Macapá, Amapá, Brazil: A single-case study

Background Waste picking is essential to urban recycling systems in emerging economies, but it is often performed under informal conditions and high physical demands, especially when collection and transport rely on human-powered vehicles. Objective To assess the ergonomic conditions of a solid-waste picker using a human-powered vehicle in Macapá, Amapá, Brazil. Methods A mixed-methods single-case study ( n = 1) was conducted during two real work routes. Direct observation was combined with NASA-TLX, RULA, OWAS, and the Nordic Musculoskeletal Questionnaire (NMQ). Ethical approval was obtained from a competent Research Ethics Committee. Results The worker reported high perceived workload, with a NASA-TLX global score of 85.33, mainly driven by physical demand, effort, and frustration. Observations showed frequent trunk and knee flexion, sustained pushing and pulling, and variable load handling under conditions of persistent mechanical instability of the cart. The representative posture showed trunk flexion of approximately 75°. Postural analysis indicated critical conditions, with a RULA score of 7 and OWAS action category 4. The NMQ revealed symptoms predominantly in the lower back, shoulders, and lower limbs. Conclusions In this case, waste picking with a human-powered vehicle showed unfavourable ergonomic conditions. Persistent traction belt instability, inadequate load handling, and irregular terrain intensified physical demands. The findings support work redesign measures, including improvements in vehicle design and task organisation, to reduce biomechanical overload and support safer work in informal settings.