The aim of this study was to reveal the age dynamics of 7-8 and 16-17 years aged pupils' interest in mastering the fundamentals of physical culture. The results of the research had allowed to conclude that the age peculiarities of schoolchildren's interest to the fundamentals of physical culture activities' assimilation are characterized by the gradual conversion from the interests "in general" to the interests in "own" individual physical culture. The gradualness of such a conversion is in combination with the age changes in scoolchildren's activities, that characterizes their independence's formation and expresses itself in the specifics of their terms with teachers and children of their age. The revealed age peculiarities of the schoolchildren's maturation at various periods of their ontogenesis had allowed to bring up the supposition about the necessity to use them when elaborating the content and orientation of the school subject-physical culture.