배송 탑차에 따른 상 · 하차 작업에서 택배 배송기사들의 신체 부하 평가

초록

Objective: The aim of this study was to evaluate the workloads of delivery workers when performing loading and unloading tasks for three types (a regular truck, a low-floor truck, which has a low loading height of cargo, and a new design EV lowfloor truck) of trucks. Background: Recently, the physical and mental loads of delivery workers were increased, causing the risk of work-related musculoskeletal disorders (WMSDs) due to the rapidly increasing volumes of parcels from COVID-19 and the demand for low-floor trucks to access apartment parking lots. Method: Ten adult men who had no musculoskeletal disorders were recruited and performed loading and unloading tasks of 5kg boxes for three types of trucks and three working zones for each truck in this study. The EMG was attached to the upper trapezius (UT), erector spinae (ES), rectus femoris (RF), biceps femoris (BF), tibialis anterior (TA), gastrocnemius (GAS), and the motion sensors were also attached to collect shoulder, back, and knee flexion angles. Subjective discomfort scores also be collected to compare pre- and post-task. Results: As a result of the experiment, muscle activity decreased by about 8.2~22.4% when working the EV truck, except for the lumbar muscle. In the case of motion, the flexion angles of the shoulder and back also decreased 8.1~40.3% and 8.1~25.7%, respectively, for the EV truck. Although the back-flexion angles when one did tasks in regular and low-floor trucks were greater than that of the EV truck, the reason why the lumbar muscle activities were lower than that of the EV vehicle was explained by the flexion-relaxation phenomenon (FRP) in the discussion section. Subjective discomfort ratings for whole-body and local body parts (neck, shoulder, arm, back) also showed that EVs and regular trucks had better subjective ratings than low-floor trucks. Conclusion: The workloads of delivery workers were less in the EV truck, which was newly designed than the regular and low-floor trucks based on the analyses of muscle activities, body flexion angles, and subjective ratings in this study. Application: The findings of this study are expected to be used as data to provide information on the physical workloads of delivery workers in low-floor trucks and are also expected to be used as fundamental data for the evaluation process for various delivery vehicles in the future.

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