A Strategy to Design a Work-Rest Schedule for VDT Operators Performing Data Entry and Mental Tasks

Abstract

An experiment was conducted with ten male subjects who performed data entry and mental tasks. Scores of subjective discomfort questionnaire, speed, accuracy, and performance of the subjects and electromyography measurements from trapezius and flexor carpi radialis muscles were recorded. Three different work-rest schedules were applied: 60-minute work/10-minute rest, 30-minute work/5-minute rest, and for the third schedule, the subjects received four breaks from Video Display Terminal (VDT) work each hour additional to a 14-minute break after two hours. Subjects were asked to enter randomly created alphanumeric data (last name, first name, and phone number) for data entry task and to solve randomly created addition and subtraction problems as mental task. Mental task resulted in a higher psychological discomfort, lower physical discomfort, and lower performance than data entry task. The results of the study suggest that the 15/micro schedule is superior to the longer and infrequent rest break schedules considering upper extremity discomfort, eyestrain, speed, accuracy, performance, and the load in trapezius muscle for both data entry and mental tasks.