University of Tennessee, Chattanooga, Tennessee
In earlier chapters, our focus has largely been on issues related to measurement and experimental types of research. Particular emphasis has been given to the validity of research and the methods put in place to ensure validity. This has largely meant that studies had to be controlled in various ways. Although this control is very helpful in maintaining internal validity, it sometimes creates an artificial environment. In doing so, internal validity can jeopardize the real-world or external validity of the research. You have also learned that not all research questions can be answered through traditional experimental research. For example, diagnostic trials do not conform to the traditional experimental model. This is an example of how research is modified to meet the needs of the research question. Because of the strict controls and manipulations needed for experimental trials, it may be more appropriate for some research to be done in a more natural environment. Ethical issues may also prohibit the use of experimental methods. For example, to study the cause and effect of a disease implies inducing the disease in individual persons. Clearly, this is unethical. For these reasons, other observational methods can be used to address important questions.
One way of studying disease and health outcomes in a population is in the context of a free-living or natural environment. It is in this context that the observation and collection of population-specific data of epidemiological research methods can be used to generate hypotheses suggestive of causal associations. An understanding of epidemiological methods is important to you as a practitioner to assess and understand the complex relationships among physical activity, inactivity, sport, health, and disease. An understanding of such concepts as the web of causation and the complex interactions among agent, host, and environment in relation to disease or injury and clinical outcomes is essential to the practice of sports medicine, exercise science, and preventive and rehabilitative care. Application of epidemiological measures of disease or injury occurrence, variation in occurrence, and the statistical measures of relative risk, odds ratio, and attributable fraction or population attributable risk contributes to a practitioner's skill level in assessing the potential cause-and-effect relationships reported in the sports medicine and exercise science literature. Becoming familiar with the study methods used in epidemiology, the sport and exercise science professional is better positioned to assess the criteria for cause and effect, as well as critically evaluate the assessment efforts used in meta-analyses and findings of expert review panels (e.g., consensus conference findings).
After reading this chapter, you should be able to answer these questions:
What are the different types of epidemiological measures used to study human populations?
How is epidemiology different from experimental research?
How is causality assessed in epidemiological research?