Posture, postural discomfort, and performance

In order to justify the costs of using ergonomically designed workplaces, it is necessary to relate improved posture to improved performance. This experiment used twelve subjects, four in each of three postural conditions. Subjects inspected printed circuit boards for 3 h with two five-minute breaks per hour. Both postural condition and time on task affected measures of posture, measures of postural discomfort, and performance. Poor defect detection performance was associated with increased forward inclination of the trunk, increased perceived discomfort, and increased frequency of posture changes. Subjects tried to maintain their defect detection performance over time by spending longer on each board, but they were only partially successful. In addition to providing positive evidence to justify the cost of ergonomic changes in posture, the results provide a simple and consistent set of measures to be used in future work.