The Effects of Delivery Truck Design on Lumbar and Posture Workload Reduction During Loading Tasks: A Comparative Study of Conventional, Low-Entry, and Newly Designed Delivery Trucks

The recent growth of the logistics industry and increased demand for parcel delivery services have led to a surge in parcel volumes, significantly increasing the workloads for delivery workers. This heightened workload, particularly from the strain on the back due to the use of low-entry trucks, has caused serious musculoskeletal disorders. Thus, there is a need for newly designed delivery trucks to alleviate this burden. This study aims to assess the impact of vehicle design on occupational health risks by analyzing the back workloads and posture of delivery workers during loading tasks on three types of trucks (conventional, low-entry, and newly designed). Ten adult males with parcel delivery experience and no musculoskeletal disorders participated in loading 10 kg boxes. The XSENS, 3D-SSPP, and AutoChecklist programs were applied to measure and evaluate the lumbar flexion angles, L5/S1 compression forces, and posture scores (RULA, REBA, AWBA), respectively. The results showed the lowest lumbar flexion angle and compression force for the newly designed truck, indicating a reduced workload during loading tasks. AutoChecklist analysis also revealed the lowest risk levels for the newly designed truck. Overall, the study suggests that loading tasks on the newly designed truck can reduce workload compared to conventional and low-entry trucks, providing evidence for workload reduction effects and offering foundational data for future delivery vehicle development and evaluation.