An analysis of scanning postures among grocery cashiers and its relationship to checkstand design.
Ergonomics 1995 Oct; 38(10):2078-2090
Scanning postures adopted by grocery store cashiers and their relationship to checkstand design were investigated. The study group consisted of 14 female and six male right handed cashiers, 17 to 50 years old, working at four medium sized retail supermarkets in the northeast and midwestern United States. Half the stores used a front facing checkstand with a vertical scanner/scale and half used a right hand takeaway checkstand with a horizontal scanner/scale. The cashiers were observed and videotaped while performing scanning tasks over a workday. Postures and movements associated with performing the tasks were coded and analyzed. The analyses focused on the hand used and the type of grip used to grasp each item, degree of elbow extension and shoulder abduction and flexion, trunk posture, and motion used to move the items across the scanner. The right hand takeaway design was associated with a significantly larger proportion of awkward trunk postures being adopted than the front facing design, the mean frequency of these postures being 46.3 versus 17.7%. Cashiers using the front facing checkstand almost always used the right hand to reach for and grasp items for scanning, whereas workers using the right hand takeaway generally used the left hand. No significant differences in shoulder posture, grip, or scanning motions were seen between use of the two checkstand designs. Cashiers at both checkstands tended to lift items more frequently than drag them when scanning large orders. Pinch grips were used three to four times more frequently than power grips by cashiers at both types of checkstands. The authors conclude that front facing checkstands dramatically reduce a cashier's exposure to awkward trunk postures during grocery scanning. Awkward trunk postures may present a risk for low back pain. Checkstand design does not seem to significantly influence shoulder posture, grasp, or scanning motion.
NIOSH-Author; Ergonomics; Grocery-stores; Biomechanics; Musculoskeletal-system-disorders; Injury-prevention; Work-analysis; Workplace-studies; Retail-workers;
Author Keywords: Musculoskeletal disorders; Work postures; Supermarket workers
Katharyn A. Grant, US Department of Health and Human Services, National Institute for Occupational Safety and Health, 4676 Columbia Parkway, MS C-24, Cincinnati, OH 45226, USA