Evaluation of ergonomic approach and musculoskeletal disorders in two different organizations in a truck assembly plant

• Potential physical risk factors were significant for the upper limbs among truck assembly operators.
• WR-MSDs symptoms were reported to be high for elbows, shoulders, hands/wrists, and lower back in assembly plant operators.
• Subjective assessment of ergonomic risks for the new cycle time was better because of organizational/technical improvement.
• Upper limb and low back risk factors were high among truck assembly operators and reference data in France.
• Job strain and psychosocial risk factors can be reduced by good quality of social support.

The aim of this study was to assess the ergonomic physical exposure, organizational and psychosocial factors in a truck assembly plant for two different cycle times (11 min and 8 min). A self-reported questionnaire was applied to evaluate subjective physical exposure, organizational and psychosocial factors by operators in two organization of an assembly process. The initial cycle time was 11 min (system A) and the new was 8 min (system B). The same work and assembly tasks had to be completed in both systems. However, the organization and distribution of the tasks and workstations were reorganized. The results of the questionnaire showed that subjective estimation by the operators regarding ergonomic risk factors was better in the new organization and self-reported WR-MSDs symptoms were fewer. However, exposure to risk factors and WR-MSDs symptoms was not statistically different between two cycle times. The findings provide better understanding of how organizational changes can modify ergonomic exposure in manufacturing assembly industries. Effective interventions are thus not only engineering solutions but also organizational and administrative adaptations.