Productivity Improvement for Optimum Utilization of a Worker's Capabilities in Repetitive Lifting Tasks

Abstract

In spite of a high degree of mechanization and automation found in industries, it has been observed that repetitive manual lifting jobs involving the handling of loads varying from a few hundred grams to as much as about fifty kilograms continue to be undertaken manually by industrial workers. One of the major and most inescapable of all tasks on an industrial shop floor is frequent manual material handling. A large number of industrial workers suffer from various types of cumulative trauma disorders (CTDs) due to ill designed manual lifting jobs and processes. A physically stressful and sustained manual lifting job needs to be viewed ergonomically in the light of workers' capabilities and after-effects of such jobs on the workers in the long run. In this paper, an attempt has been made to identify important factors that have a bearing on the capabilities of an industrial worker involved in such repetitive manual lifting jobs. This paper focuses on the ergonomics aspects of the manual lifting with particular reference to physical capabilities and limitations of a worker. Critical factors such as age, weight, height, oxygen up take, heart rate (HR), pulse rate (PR), electromyographic measurements (EMG), loads (weight of the material), distance of the load from the operator, posture, frequency of lifts, etc. have been considered. Aspects such as operational process sequence or the exact nature of the load to be lifted is situation specific in an industry. Some of the industries that may benefit from this work are tire manufacturing, railroad, automobile, chemical, ceramic, brick and pottery, glass, cement, steel and iron, building and construction, and defense related industries. An integrative ergonomic approach for evaluating a worker's capabilities for the job requirements has been developed. It is important to consider all approaches such as physiological, biomechanical, psychophysical, psychological and biochemical to optimize the worker's capabilities in such types of physically demanding jobs. In order to optimally utilize a worker's physical capabilities in such tasks an integrative systematic approach is recommended so that a worker's physical capabilities are correctly matched and production is optimized benefiting both the worker and the organization.