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Introduction: Manual lifting operations continue to play a key role in the industrial and service sectors, inflicting physical strain on the musculoskeletal system, despite advances in automation. As a result, an experiment is carried out to assess the impact of two lifting task parameters; weight and height, based on the estimation of subjective responses and biomechanical loading, while lifting the weight symmetrically in the sagittal plane. Also to recommend the safe limit for manual lifting tasks. Methods: Twelve volunteer male students in the age group of 21 to 26 years performed lifting tasks from floor to 5 different heights (below the knee to ear level), with 5 different weights (10 to 20 kg) using free-style lifting techniques. The load pan with no handle was used for lifting weight, which is typically adopted in the Indian building construction field. The subjective estimate was obtained using workload assessment by body discomfort chart. The biomechanical loading (loading rate) for each lifted weight and height was collected using a force platform. Results: The results showed that heavier weights produced higher stresses than lower weights. The loading rate was found to be almost similar at waist or knee level. The loading rate was observed to be linearly increasing after waist level. The overall workload rating seems to be a good correlate with the mean loading rate to some extent. Conclusion: It is proposed to keep the maximum acceptable lifting weight from floor to knee, up to the ear level is 15 kg, to prevent any musculoskeletal or chronic injury.

Human involvement, as a manual work, is still prevailing in modern manufacturing activities because of a limited workspace which does not allow the use of mechanical devices or robots. The manual materials handling (MMH) is an inefficient way of performing a task and is considered hazardous in addition to wastage of the great amount of human energy. Moreover, subsequent accidents and injuries can be physically and economically very disturbing and costly. Ergonomic evaluation of MMH has largely been based on task analysis approach, where the jobs are broken down into simpler tasks and studied. But there is the lack of clarity in the use of terms defining various MMH activities. Therefore, the need arises to minimize MMH tasks-related injury, using specific design approaches, so that its demand stays within the capacity of the worker. The aim of the present study is to demonstrate the applications of biomechanics and explain how the use of biomechanics can reduce the risk of an initial injury. The study also indicates the impact low back pain may have, on performing the task. To achieve this, a systematic review of specific design approaches (biomechanical, physiological, epidemiological, and psychophysical approaches) of various tasks in the workplace has been made to identify a situation that has a higher risk of workplace injury. This review of literature will be helpful to evaluate MMH task design or work practice so as to identify an effective and efficient solution, to ensure physical changes to the workplace. The study will also be helpful to provide a set of recommendations, to reduce or prevent the presence of musculoskeletal disorders and enhance production.