Definition of athletes and classification of sports.

The first part of this chapter will provide an accurate definition of the term athlete. In this book, an athlete is considered to be an individual who is engaged in physical activity and exercise on a regular basis. This definition is intentionally wide, to include all those individuals regularly participating in some type of physical activity. The population of athletes is quite heterogeneous and further descriptors should be provided when describing an athlete’s population. These necessary descriptors include level of commitment (e.g. recreational, competitive, professional), exercise training parameters (e.g. frequency, intensity) and epidemiological characteristics (e.g. gender, age). Taking the different physical demands induced by different exercise components into account, several attempts have been made to classify athletes according to the specific impact of these components on performance, body composition and, of particular importance, on cardiovascular adaptation. In the second part of this chapter, the main characteristics, objectives and potential limitations of the two most used classification of sports will be addressed: (a) the traditional Mitchell classification, summarizing different sports into nine subgroups as defined by their percental proportion of static (i.e., predominantly strength-related) and dynamic (predominantly endurance-related) exercise components, and (b) the recent classification of sport disciplines according to the relative isometric and isotonic components of exercise and resulting cardiovascular adaptation. These classifications provide clinical and scientific support to understand the impact of exercise on cardiovascular adaptations in athletes and to distinguish them from pathological alterations that are associated with an increased risk of experiencing cardiovascular events during sports.