Workload assessment in manual materials handling tasks in rice mills in India

BackgroundManual materials handling (MMH) tasks in rice mills in India are labour intensive.ObjectiveInvestigation of physical workload on seven manual material handling (MMH) tasks among male workers in rice mills and comparison of the VO₂ obtained from experiments in the present study with the models developed for Indian workers.MethodsExperiments were performed to measure the working heart rate (HR) in the eight rice mills and submaximal test was performed to measure oxygen uptake (VO₂) in the laboratory. A model was developed to estimate the VO₂ during MMH tasks for workers in rice mills.ResultsThe workload was observed to be comparatively higher in carrying 50 kg rice bags from the godown to vehicles and for this task, the mean values of working HR, ΔHR, peak HR and VO₂ were 129 bpm, 56 bpm, 150 bpm and 1.17 l/min, respectively. The workload to fill rice in the bags was relatively lower and the working HR, VO₂ and ΔHR were 110 bpm, 0.95 l/min and 40 bpm, respectively. The VO_2max of all the tasks was higher than the 35% VO_2max for 8-h work for Indian workers. The VO₂ prediction models developed so far for Indian workers underestimated the actual VO₂ in the MMH tasks in the rice mills. The accuracy of the developed model was 0.92.ConclusionAccording to workload classification, MMH tasks in the rice mills varied from moderate to heavy tasks. There is a need for reducing the workload of the rice mill workers.