Physical variation is generally considered to be an important factor influencing the risk for musculoskeletal disorders in repetitive work, but a comprehensive scientific basis for this assumption has not been available. Thus, the Swedish Work Environment Authority requested the Centre for Musculoskeletal Research at the University of Gävle to review scientific standings regarding physical variation and its effects.  In total, 56 articles were included in the review. The results showed that occupationally relevant studies of the effects of physical variation are few, and that the effectiveness of initiatives promoting variation has also been studied to a limited extent. Thus, current research cannot provide a clear answer to what an effective combination would be of work tasks in a job in the context of physical variation, let alone the optimal time distribution of tasks in a short (hours, days) and long (weeks, months, years) perspective. Also, gender aspects of physical variation were considered to a very limited extent. There is a need for more studies of relevant initiatives aiming at creating increased physical variation by changing the contents of work or its temporal structure; including studies placing this issue in a gender perspective.