The relationship of work pace to back injury in a supermarket distribution center.

This is a retrospective case control study of the relationship between work pace of selectors at a food distribution center and the subsequent incidence of compensable back injuries. Subject employment records for 1 month were evaluated for degree of variation of actual-from-scheduled performance of weekly work pace as selectors, defined in terms of absolute values (either above or below criterion). Subjects were divided among those with no compensable claims for back injury (n=14) and those with multiple compensable claims (n=12) over a 2-year period of employment. Other dependent measures included percentage of tasks that each group completed by or before the scheduled criterion and the percentage of time working that employees engaged in selector activities. The groups differed in age, averaging 38 vs. 31 years for the no claims and multiple claims groups, respectively. The groups did not differ in terms of educational background or length of service at the food distribution center. The major finding was that there was a group difference in the actual-from-scheduled, absolute mean performance values. As expected, the multiple claims group had significantly more variability in their work pace than the no claims group. The no claims group also worked significantly more often at or faster than criterion and spent, on average, a higher percentage of their day performing selector duties. These preliminary results suggest an association between work patterns and occupational injury that warrant further research, such as a clinical trial manipulating the scheduled work criterion.