Work-related symptoms and checkstand configuration: an experimental study

Biomechanical evaluation of supermarket cashiers before and after a redesign of the checkout counter

An experiment was carried out on supermarket cashiers to evaluate the time, kinematic and electromyographic changes, in both sitting and standing positions, following the redesign of a checkout counter. The novelty of the prototype checkout counter is a disk wheel placed in the bagging area, which is designed to avoid the cashier having to manually push products along the bagging area. The kinematic evaluation was based on the upper limb and trunk range of motions (RoM). The electromyographic parameters assessed were mean and maximum muscular activations. Three factors were taken into account: design (before and after redesign), posture (standing or sitting) and bagging area (anterior or posterior). The results show that the RoM values are lowest after the intervention and in the standing position. Mean and maximum muscular activation patterns are similar. Differences related to the bagging area in which the goods were released also emerged. The disk wheel represents a valid aid for reducing biomechanical overload in cashiers; the standing position is biomechanically more advantageous. Practitioner Summary: EMG and optoelectronic motion analysis systems are useful for the quantitative assessment of the effects of the redesign of the workplace biomechanical risk. Our results suggest that a disk wheel positioned in the bagging area reduces the biomechanical risk for cashiers and increases time spent resting.

Field evaluation of a new grocery checkstand design

A novel express checkstand with basket cut-out was developed and evaluated in a small grocery store chain. Eight checkers performed three trials of simulated grocery checkout work with actor customers using both old and new checkstand designs. Usability was assessed by survey, structured interview and observation. Time-motion video analysis was used to evaluate differences in body postures, motions, and productivity. The new express checkstand design, which lowered and angled the presentation of the grocery basket, significantly (p<0.05) reduced right wrist flexion duration and repetition, and right arm elevation repetition. No significant differences were found in job cycle time between designs. These results demonstrate the utility of a new express checkstand design that could reduce extreme postures and motions with no loss in productivity.

Working at the check-in: consequences for health

No body of literature exists related specifically to the occupational health of airport check-in workers. The problems encountered by airport check-in workers are typical of other service-sector occupations with similar work-related health hazards, particularly those characterized by a high level of demand with low worker control, performed predominantly by women. The knowledge gap could be narrowed by broadening the scope in both traditional occupational health and ergonomics studies to take into equal consideration jobs performed by women. In an attempt to reduce the knowledge gap specific to airport check-in workers, literature was reviewed on several other worker populations whose job characteristics include elements similar to airport check-in work: computer clerical workers, supermarket check-in workers, and airport baggage handlers. This cross-population review identified the major elements that have been studied in the comparison groups, compared with the factors examined in a study of check-in workers. The review demonstrates that jobs that may appear completely different from the outside, might, upon closer examination, have numerous common exposures from a variety of sources. Thus, knowledge about one job may be useful for another that has not been investigated. The literature review reveals that it would be useful to extend to airport check-in workers recommendations from studies of the three comparison populations.

Effects of sitting versus standing and scanner type on cashiers

In the retail supermarket industry where cashiers perform repetitive, light manual material-handling tasks when scanning and handling products, reports of musculoskeletal disorders and discomfort are high. Ergonomics tradeoffs exist between sitting and standing postures, which are further confounded by the checkstand design and point-of-sale technology, such as the scanner. A laboratory experiment study was conducted to understand the effects of working position (sitting versus standing) and scanner type (bi-optic versus single window) on muscle activity, upper limb and spinal posture, and subjective preference of cashiers. Ten cashiers from a Dutch retailer participated in the study. Cashiers exhibited lower muscle activity in the neck and shoulders when standing and using a bi-optic scanner. Shoulder abduction was also less for standing conditions. In addition, all cashiers preferred using the bi-optic scanner with mixed preferences for sitting (n = 6) and standing (n = 4). Static loading of the muscles was relatively high compared with benchmarks, suggesting that during the task of scanning, cashiers may not have adequate recovery time to prevent fatigue. It is recommended that retailers integrate bi-optic scanners into standing checkstands to minimize postural stress, fatigue and discomfort in cashiers.

Packing products for customers: an ergonomics evaluation of three supermarket checkouts

The introduction of laser scanners at supermarket checkout areas has resulted in previous ergonomics studies focusing specifically on the scanning process and associated cumulative trauma disorders in the hands and arms. Few studies have evaluated the increased musculoskeletal load and exertion of checkout staff when they are also expected to pack the products into bags for the customers. This paper describes an ergonomics evaluation of three different designs of checkout workstation, which require the operator to stand when they scan the products, pack them into plastic bags and transfer the packed bags to the customer. Musculoskeletal load and exertion associated with the different checkouts were measured using OWAS, heart rate recordings and ratings of perceived exertion. In addition, subjective rankings of the workstations were obtained and the productivity associated with each design examined as part of the evaluation. Some of the variables measured showed significant differences in postural load between the workstations. The results of the evaluation formed the basis of recommendations for an improved workstation design. Some of the suggestions made to reduce postural load and increase productivity include positioning the weigh scale to the side and the bag frame beneath the scanner.