Introduction: The greatest similarities in body constitution were noted in competitors practising the same discipline. The similarities increase with the training level. A typical body constitution for a given discipline not only favourably affects athletic performance, but is also the factor preventing sportsrelated contusions. The ability to maintain body equilibrium, together with somatic constitution, are the basic selective criteria in rhythmic gymnastics.
Aim of the study: The objective of this paper was to determine somatotypes, to evaluate the ability to maintain dynamic body equilibrium in girls practicing rhythmic gymnastics and to develop model characteristics enabling early diagnosis of the disorders equilibrium system function.
Material and methods: The sample comprised 19 girls aged 8-11 years, practising rhythmic gymnastics. For the evaluation of the competitors' somatotypes, the Heath-Carter method was used, based on the classic concept of Sheldon's body constitution components. Body equilibrium level was evaluated by means of posturography.
Results: The mean values of the endomorphic component I, mesomorphic component II and ectomorphic component III in the gymnasts were 2.65+/-1.29, 2.45+/-0.37 and 3.95+/-0.64 respectively. The mean body mass index (BMI) value for this cohort was 15.32, which means advanced slimness. The level of dynamic equilibrium is determined by the following mean values: the time of reaching the equilibrium, the way of reaching it and the duration of stay at the defined point. The model of above mentioned indicates was developed based on the analysis of it's best results.
Conclusion: Body constitution type in the qualified gymnasts is characterised by the prevalence of the ectomorphic component. The study results indicate that female gymnasts are generally slim and lean. It is necessary to monitor BMI in order to exclude weight-related disorders and to observe the changes with age. The poorest result was found when the gymnasts bent in the backward direction as this body position is most difficult to assume and to maintain body equilibrium as compared to all other directions.