The present work addresses the task profile of the modern world-class tennis and the resulting requirements on the training practice, with special attention to the long-term performance. A first empiric part reviewed systematically the impact of changes in the training load by numerous upraised parameters in 20 semi-professional tennis players. In this context an intensive training method and a match-related training method are compared by two different ball machine tests and a match-simulated training form. In addition the results of an expert's questioning of 16 certified and experienced tennis trainers provide important information of training practice in high performance tennis. The second part results of a comprehensive test battery regarding the diagnosis of tennis specific running speed and strength of cadre athletes (n=160/year). Results of the DTB-Talent-Cup (U12) in the years 2004 to 2007 are presented. This part focused on the development of speed and strength performance in the observation period and their significance in relation to the task profile in the modern top tennis. In addition, gender differences and a possible association between the rankings in the diagnostics and the placements on the respective DTB rankings are reviewed. The present findings offer a numerous relevant practical insights. The high professionalization and the increased task profile in today's top tennis require advanced training concepts. It is imperative to start professional training since childhood and to exercise very systematically, individually and predominantly intensely. The optimization of the training quality can make a decisive contribution with regard to a successful tennis career.