Industrial workers performing repetitive manipulation tasks are subject to work-related musculoskeletal disorders (WMSDs) which could manifest as localized joint fatigue resulting from repeatedly moving the same joints. With the promise of collaborative robots (cobots) directly interacting with humans, a research direction which investigates using cobots to reduce WMSD risk has emerged. Focusing on repetitive co-manipulation tasks, some studies suggest using cobots to induce motion variability, recommended to reduce WMSD risk, in order to minimize localized fatigue.