Since physical activities affect the quality of life and activate a complete locomotor system, sports and physical activities can be treated as a determinant for a harmonious development of all child's characteristics and anthropological characteristics. Because, childhood and youth are the most important formative periods, and some segments of development, for example, specific motor skills can be developed only with means used in sports, this research was conducted to find out do the fitness program (aimed at improving strength) after eight weeks had a positive effect on body composition and mobility and stability of subjects. A control group consisted of 11 female subjects and experimental group were 11 female subjects aged 16 years. The effects of the program on the fitness condition of the subjects were determined by assessing the body composition parameters (data obtained using the Body composition analyser TANITA BC-418)-the total percentage of fat tissue (FAT), the percentage of fat tissue segmentally (percentage of fat tissue of the left leg (FATll), right leg (FATrl), left arm (FATla), right arm (FATra) and body (FATb)) and estimation of mobility and stability levels-based on the application of Functional movement screening (FMS) method (seven tests) before and after the program is implemented. The success of the implemented program was confirmed because the program showed a statistically significant difference between the mobility groups of the subjects in the experimental in relation to the control group (deep squat t= 3,464 p= 0,006, step over a hurdle t= 2,390 p= 0,038, active lift of a stretched leg t= 2,887 p= 0,016, rotatory body …