Unhealthy lifestyle and limited physical activity tend to be main factors adversely affecting the development of the young generation. The aim of this study was to evaluate the prevalence of postural disorders in the sagittal plane as well as to compare posture types taking into consideration physical activity of the examined children. The data was gathered in 2002 and 2008 in Polkowice. The examined group consisted of 2398 children - boys and girls aged 7 to 11. Body posture was measured by means of the photogrammetric method with the use of Moire pattern. A questionnaire was used to gather information concerning the amount of time outside of school spent on physical activity, watching TV or playing computer games. While comparing the prevalence of postural disorders in 2002 and 2008 an overall increase was observed - higher in girls than in boys. The posture types distribution was comparable in both studies. Kyphotic and balanced posture types were predominant in boys, whereas in girls lordotic and balanced types were more frequent. The questionnaire showed that between 2002 and 2008 physical activity after school decreased.