Effects of exercise breaks on performance, muscular load, and perceived discomfort in data entry and cognitive tasks

An effective work-rest schedule is an economical way to potentially reduce physical and psychological problems associated with computer usage. In this study, three different work-rest schedules were investigated: 60-min work/10-min rest, 30-min work/5-min rest, and for the third schedule (15/micro), the participants received four breaks from each hour in addition to a 14-min break after 2 h (three of these breaks were 30 s in length and the fourth break was 3 min in length). The study also considered the effect of the type of task. Participants were asked to enter alphanumeric data as a data entry task and to solve addition/subtraction problems as a cognitive task. The results indicated that the effect of work-rest schedule was significant on various perceived discomfort categories and the performance of the subjects. Similarly, the type of task had significant effects on discomfort, performance, and muscular load levels. The 15/micro schedule was superior to the other schedules in terms of discomfort levels of the neck, back, and elbow/arm, eyestrain, speed, accuracy, and performance for both tasks. The lowest levels of trapezius muscle tension for data entry and flexor carpi radialis (FCR) for cognitive tasks obtained with the 15/micro schedule. The cognitive task resulted in a higher psychological discomfort (nervousness, tiredness, dizziness, and headache), but lower physical discomfort and performance than the data entry task. The results of the study suggest that the 15/micro schedule is preferable to the longer and infrequent rest break schedules considering upper extremity discomfort, eyestrain, speed, accuracy, and performance of participants. (C) 2004 Elsevier Ltd. All rights reserved.