Objective: This study aims to quantitatively evaluate the effects of a Transport Assist Device (TAD) on physical strain and efficiency during harvest crate handling tasks at fruit sorting facilities.
Background: Handling harvest crates at fruit sorting facilities involves intense physical labor, which is a primary cause of work-related musculoskeletal disorders (WMSDs). The introduction of a TAD is being considered as a solution to this problem. It can significantly reduce the physical load on workers without drastically altering existing processes. However, quantitative evidence of its real-world effectiveness is needed to justify its on-site implementation.
Method: A within-subjects experimental design was used with six healthy male participants. The study compared manual handling (WO) with TAD-assisted handling (W). Task 1 involved a short repetition of five crates to measure muscle activity (%MVC) via electromyography (EMG) and perceived exertion using Borg's RPE scale. Task 2 involved a longer repetition of 30 crates to measure total working time.
Results: Using the TAD significantly reduced physical strain. The overall average muscle activity (%MVC) was reduced by 42.2% (p < 0.001) in the W condition compared to the WO condition. The 50th and 90th percentile muscle activities also showed significant reductions, indicating that the device effectively alleviated both sustained and peak loads. Perceived exertion scores were also significantly lower. However, the working time for the W condition increased by 112.3% (372.5s vs. 175.5s), attributed to device operation time and setup procedures.
Conclusion: The TAD is highly effective in reducing the physical burden of workers, as demonstrated by the significant decreases in muscle activity and perceived exertion. The notable reduction in muscle activity shows the potential of such equipment to directly mitigate the risk of WMSDs. While the increase in working time is a current limitation, this can be improved through design enhancements, such as a two-stage speed control and quick-release grips. This study provides crucial quantitative data for developing and evaluating practical ergonomic solutions in agricultural settings.
Application: The findings provide a valuable basis for developing effective safety equipment in agricultural environments. This data can also serve as a practical reference for assessing the economic and operational feasibility of introducing new equipment to enhance safety and reduce WMSDs.