The indirect and direct cost of occupational musculoskeletal disorders (MSDs) cause a significant burden on the health system, and lower back pain (LBP) is associated with a significant portion of MSDs. In Australia, there is a high prevalence of MSDs for health care workers, such as nurses. Two digital human models (DHMs) Siemens JACK and imk EMA were used to investigate if hospital bed pushing, a simple task and hazard that is commonly associated with LBP, can be validly simulated and ergonomically assessed in a virtual environment. While JACK and EMA have implemented a range of common physical work assessment methods, the simulation of a dynamic task such as bed pushing remains a challenge due to the complex interface between the environment, object, interface and other factors, which can only be insufficiently modelled. In addition, it was found that both human simulation systems present limitations that need to be considered during the interpretation of the results. This research highlights the limitations in the DHMs studied and the need for further research in the area. In particular, the implementation of legacy two dimensional, low resolution ergonomic methods in an analytic, high resolution three dimensional software system is critically reflected.