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Introduction: Repetitive work is associated with increased risk for musculoskeletal disorders (MSDs). We collaborated with a commercial laundromat to design and implement a job rotation (JR) inspired by the Goldilocks Work paradigm. The JR was designed to increase within-worker variability and positively impact worker health. The aim of the study was to evaluate the effectiveness of the JR by assessing pre-post changes in within-worker variability (assessed as within-worker variance) and health related outcomes.

Methods: This pre-post case study had a 12-month follow-up after company implementation of the co-created JR intervention. All day-shift operations employees (N=57) were included in the JR. We measured trapezius (Trap) and forearm (FA) muscle activity at baseline for all 21 JR tasks and created a task exposure matrix (TEM). Estimates of within-worker variance were made for all individual workers at baseline, for the planned JR, and for the actual JR observed at follow-up using the TEM combined with the tasks performed (self-reported at baseline and follow-up) and the planned JR schedule. Variance estimates for the planned and actual JR were compared to baseline estimates to determine the theoretical and actual effects of the JR. Self-reported health-related outcomes on fatigue, recovery and MSD symptoms were collected by survey at follow-up. JR delivery and adherence to were assessed.

Results: At follow-up, the JR intervention had been delivered to 65% of all day-shift operations workers, all of whom demonstrated adherence to the JR. The planned JR showed the potential to increase the average within-worker variance in Trap and FA muscle activity by 45% compared with baseline. At follow-up, the actual JR was shown to have achieved approximately 80% of the planned increase. Positive health-related changes were also evident at follow-up: approximately 40% of participants reported both lower physical and mental occupational demands, and over 50% of workers reported less fatigue after work and feeling more rested and recovered when starting a workday at follow-up compared to baseline. The number of workers experiencing upper extremity MSD problems ‘fairly often’ or ‘very often’ showed a slight increase at follow-up compared to baseline.

Discussion: This is the first JR study to demonstrate a positive effect on both within-worker variability and health related variables. Consideration of variability is key to JR studies since the proposed effects of a JR on improved musculoskeletal health are expected occur through JR-related increases in variability. Further, the positive findings on decreased self-reported physical and mental demands and fatigue and increased recovery lend support for the theory that a re-distribution of existing tasks can increase the average within-worker variability for the workers in the JR and that this increase may lead to health benefits. However, no positive changes in MSD were associated with the JR.

Conclusion: This case study demonstrated both the potential (planned) and actual effectiveness of the JR to increase within-worker variability in Trap and FA muscle activity. Further, the findings suggest the JR had positive impacts on health-related outcomes.