The modern basketball game requires careful guided selection and training of juniors, based on the most suitable somatic growth and development, which can allow to the player the acquisition of an efficient techniques and a great functional capacity of the body to support motrical acts with major efforts, required by competitive activity at the level of international requirements. In modern process and methodology of sports training a number of important changes have occurred in juniors instruction and training, changes which involves the existence of some patterns of training and preparation. At the Junior U18, RBF has formulated „a theoretical model of performance in basketball”, being determined by the nature of the rules of the game and by national requirements. Within this theoretical model of performance, somatic type holds a determining role. The purpose of this study was to demonstrate that the biological preparation is an important part of sports training, thereby causing a significant improvement of biological standard of high performance athlete.