Background: The main aim of the present study was an attempt to answer the enquiries concerning the influence of physical training on morphological changes (anthropometric indicators), capability of anaerobic work and their interactions with a natural development of youth in pubertal and post-pubertal age.Material/Methods: The technique of parallel groups was used: experimental (handball trained [TR]) and control (not trained [NT]). The research period comprised two consecutive years. Once per year selected somatic parameters, body composition, biological age, and anaerobic parameters were determined by means of 30 s Wingate Anaerobic Test (WAnT).Results: Results have shown the high intensity of boys' biological development in circumpubertal age in response to several years of training handball. A further analysis indicated smaller dispersion of parameters describing the growth and physiological development of the TR group than in NT. The results suggest that handball training caused a significant improvement in morphological and functional indicators. Consequently, capabilities of physical effort increase and a more harmonic development is achieved. Moreover, the results have shown that capabilities of anaerobic work in the TR group have differently depended on the time of progressive development, whereas in the NT group there has been an increase in these capabilities in relation to the age of the examined boys.Conclusions: Several years of handball training did not influence the increase in anaerobic efficiency of pre-pubertal age boys. On the other hand, handball training in pubertal and post-pubertal age boys caused a statistically significant increase in maximum anaerobic power (MPWAnT). A high positive correlation between weight and MPWAnT confirms a relationship between anaerobic power and body growth during puberty.