ABSTRACT
The World Health Organization defined health in its broadest sense as: “a state of complete physical, mental and social wellbeing and not merely the absence of disease and infirmity” but numerous definitions exist. To understand research methods, familiarity with language used is crucial so this chapter introduces physical activity and health–related terms to provide clarity for the reading of subsequent chapters. The numerous definitions of health are provided and discussed and the importance of public health interventions to prevent and manage disease is realized. Achieving and maintaining good health is an ongoing process that is influenced by personal strategies including undertaking physical activity. Physical activity is defined and described as well as exercise, sedentary behaviour and physical inactivity, all of which are distinctive behaviours. Epidemiology is the study of the distribution and determinants of health-related states or events in specified populations, and the application of this study to the control of health problems. Measures of the occurrence of health-related outcomes are basic tools of epidemiology but are complex and often misunderstood. The chapter will finish by defining prevalence, incidence, relative risk, population attributable risk and odds ratios using hypothetical examples to further understanding.
