Physical Activity: Definitional Issues and Knowledge Gaps

This chapter presents issues associated with the definition of physical activity, and potential ways these definitional issues can help fill gaps in our knowledge about physical activity as an intervention strategy to address public health problems. Why does this matter? Physical activity, including exercise, sport, recreation, play, and its many other manifestations, is generally thought to be a positive thing. This is true in popular culture and also in much scientific literature. However, while the scientific evidence is compelling, and has even led to the development of national guidelines for public participation in physical activity, it is rare for experts to clarify what types of activity bring the most benefit. This chapter explores the current base of knowledge and suggests ways that future scientific studies can help clarify these uncertainties.