1. Introduction
Work-related injuries and occupational diseases have become an increasing concern to employees, employers, and governments because of big impacts on workers’ health and productivity. Of the 10.8 million Australian who worked sometime in the previous 12 months, 6.4% experienced at least one work-related injury or illness (Australian Bureau of Statistics, 2007). Work-related injuries and diseases affect 15–20% of all Americans (Melhorn, 1996). Musculoskeletal disorders (MSDs) were the main reasons for work-related consultations in general practice (Reiso et al., 2000 and Weevers et al., 2005). A survey in the United States found that more than one million workers with MSD missed time from their jobs at a cost of more than $50 billion a year (National Academy of Sciences, 1999).