The presented thesis discusses the complex structure of strength training in cross-country skiing. The detailed introductory definition of the aspects strengths and training is followed by an examination of the specific aspects of training organization. The main part of this thesis highlights the strength training in cross-country skiing. Due to this purpose, a variation of strength training methods, which are divided into the parts: strength endurance training, maximum strength, speed strength and reactive force, as well as common strength training complements, will be revised. Furthermore, the periodic categorization of strength training through the year, as well as the field specific strength requirements will be discussed. The final part will deal with adolescence training within cross-country skiing with a focus on training organization of strength training. To be able to provide a broad insight into the topic, the adolescence training is going to be divided into prepupertal phase and pubescence and adolescence itself.