Introduction:
The purpose of the work was to assess the static and dynamic postural stability and to identify the risk of the locomotor system injuries in 14-year-old boys and girls.

Methods:
The study involved a group of 40 girls and 43 boys aged 14 who regularly attended physical education classes, 4 hours per week. The examination of static balance was carried out with the modified version of the first test of the Eurofit Physical Fitness Test Battery – the Flamingo Balance Test, and dynamic balance assessments were performed with the Y-Balance Test by using a specially designed test tool, the so-called Y-Balance Test Kit. To differentiate between the higher and lower risk of a motor system injury, an index proposed by Butler was applied.

Results:
With respect to both static and dynamic balance, the results obtained by the studied girls did not differ statistically significantly from those of the studied boys.

Conclusions:
In the group of girls, the index recommended by Butler was exceeded by 78% of the subjects for the left lower limb and by 80% of the subjects for the right one, while in the group of boys, the respective values were 74% and 79%. This indicates that the risk of a motor system injury among the study subjects was low.