Comparisons of Endurance Time Models in the Prediction of Pulling Tasks  
Author Kai Way Li
Co-Author(s) Fan Tang; Cannan Yi; Lu Peng
Abstract Truck pulling is one of the common manual materials handling tasks which could result in musculoskeletal injuries. The endurance time has been one of the major terms in studying both the musculoskeletal disorders and job design for manual materials handling tasks. The endurance time for sustained pulling tasks has been rarely discussed in the literature. The objective of this study was to compare the maximum endurance time for pulling tasks using the models in the literature. A simulated truck pulling experiment was conducted. Ten human participants were recruited. The participants pulled a handle simulating that of a pallet truck under two loading conditions until they could not pull any longer because of muscular fatigue. Their maximum endurance times were recorded. The predicted maximum endurance times for the simulated pulling were calculated using the MET models in the literature. The prediction errors were determined using the mean absolute deviation. It was found that all the MET models from the literature, compared in this study, underestimated the maximum endurance time of our pulling tasks. The model from Mat et al. provided good estimates if the fatigue rate k was 0.3 other than k=1. It was concluded that task-specific endurance time models, instead of those body segment and posture-specific models, are required to have acceptable estimates of the endurance time for pulling tasks.
Keywords manual materials handling, muscular fatigue, musculoskeletal disorder, job design
    Article #:  23-200
Proceedings of the 23rd ISSAT International Conference on Reliability and Quality in Design
August 3-5, 2017 - Chicago, Illinois, U.S.A.