The first volume includes the essential sports biology and training science fundamentals that are important for understanding the training of the main forms of motor stress. Starting from the phenomenon of adaptation as a prerequisite for athletic training, the basics of training theory are presented, including the components of load, training principles, as well as training planning and control. Additional focuses include strength and speed training, with the corresponding anatomical and physiological foundations of the musculoskeletal system being introduced first. Both strength and speed are examined in terms of their significance for athletic performance and health, their trainability, their different manifestations, as well as their various training methods and content for development. Furthermore, the specific characteristics, dangers, and risks of such training at different age levels are addressed.