ABSTRACT
An understanding of epidemiologic methods is important for the clinical exercise physiologist to assess the complex relationships between physical activity and health and disease. It is essential to the practice of preventive and rehabilitative care to understand the web of causation and complex interactions among agent (exercise), host (individual), and environment (affects transmission of agent source to host) in relationship to disease/injury and clinical outcomes. Application of the epidemiologic measures of disease/injury occurrence, variations in occurrence, and statistical measures of attributable risk and population attributable risk contribute to the clinician's skill level in assessing potential cause-effect relationships reported in the literature about exercise medicine, physical activity, and public health. By becoming familiar with the study methods used in epidemiology, the clinical exercise physiologist will be better positioned to assess criteria for a cause-effect relationship as well as to critically evaluate the assessment efforts used across a variety of study designs and applications of epidemiology in clinical research and practice.