Musculoskeletal symptoms associated with posterior load carriage: An assessment of manual material handling workers in Indonesia

BACKGROUND: Concerns have been raised regarding the high prevalence of musculoskeletal symptoms (MSS) among manual material handling (MMH) workers. However, limited investigations have been undertaken among one large group of workers using a particular MMH method called posterior load carriage (PLC). This is typically done without the use of a backpack in developing countries, and involves exposure to known risk factors for MSS such as heavy loads, non-neutral postures, and high levels of repetition. OBJECTIVES: To 1) determine the types and prevalence of MSS among PLC workers and the impacts of these MSS on workers, 2) explore job demands potentially contributing to MSS, and (3) obtain input from workers regarding possible improvements to facilitate future interventions. METHODS: Structured interview applied to 108 workers to assess PLC worker characteristics and job demands in eight cities in Indonesia. RESULTS: MSS were reported in all anatomical regions evaluated, with symptoms most commonly reported at the lower back (72.2%), feet (69.4%), knees (64%), shoulders (47.2%), and neck (41.7%). Logistic regression indicated that MSS in the lower back were associated with longer work hours/day, MSS in the hands were associated with load mass, and MSS in the ankles/feet were associated with stature and load carriage frequency. MSS were reported to interfere with daily activity, but only few workers sought medical treatment. Possible improvements included the use of a belt, hook, or backpack/frame, and changes in the carriage method. CONCLUSIONS: The study suggests that PLC workers incur a relatively high MSS burden. Future studies are needed to develop and evaluate practical interventions and specific guidelines to improve working conditions and occupational health and safety for PLC workers.