The aim of this chapter is to introduce the reader to some of the general aspects of the terminology and basic concepts related to the practice of physical exercise and sports training . A working understanding of these concepts enables the practice of physical exercise and its relationship to fertility in men and women to be placed in the correct context.

Such knowledge is fundamental for an in-depth analysis of the adaptive responses that take place as a consequence of training and their relationship with performance, but it also enables the relationships to be established between physical exercise and improvement in health, both in a sportsperson and a physically active individual. It is a well-established fact that an active lifestyle has important benefits for people’s quality of life [1], and that sedentary habits are associated with a deterioration of health in general [2]. Intense sporting activity, however, as opposed to light exercise undertaken on a regular basis for recreational purposes, entails by its very nature a certain level of risk that needs to be eliminated, or at least reduced, if it is to become a healthy and non-harmful occupation for the sportsperson.

In this chapter, certain aspects of these points will be addressed that allow a new perspective on all these concepts, from a point of view that is more in line with the actual needs of health-related interventions in the prescription of physical activity . Finally, some proposals will be put forward, enabling improved oversight of the exercise “dose” as a fundamental factor for understanding the relationship between physical exercise , health, and fertility.

From the classical or traditional point of view, the training “workload” has been defined in terms of four fundamental variables: frequency , volume, intensity, and recovery . Although it may be necessary to modify some of these parameters, what follows is an attempt to give a brief description of the parameters from the classical perspective [5–12]. The appropriate management of these factors will cause an adaptive response in the sportsperson’s organism, which should have direct repercussions on sporting performance [13–15].

The variables of frequency, volume, and recovery are relatively easy to ascertain and quantify (especially when dealing with endurance events) , whereas the intensity variable turns out to be a more complicated parameter, despite being a key determinant in the adaptations that come from training [16]. Thus, it is necessary not only to give a definition of these factors but also relate them to the type of sport being undertaken (endurance or resistance) , given that this governs the very definition and the means of ascertaining the factors.