Aim of research. Basing on the results of the researches conducted on 3221 girls from Małopolska in years 1996-2005 some hypothesis were verified about ontogenetic period ap-pearance of: the negative influence of too low and too high fatness level on the positive health measures level, and the similar structure of the physical efficiency analyzed referring to health and the similar strength of the correlation connection between its elements and the height-weight index (Quetelet II) sorted in groups according to BMI level. Methods. The results of the positive health indexes were analyzed such as: the basic somat-ic features, antropometric indexes, the oxygen efficiency (VO2 max), motor ability tested on Eurofit and MTSF tests. Basing on the average value and the standard aberration of BMI all tested girls were divided into 3 groups: 8-10, 13-14, 17-18. In every group the range and the trend of the considering features differentiations were discerned and only in two groups (above and below the range of 1 SD BMI) the concentration analysis was conducted where the strength of the correlation connection between the elements of the physical efficiency structure, tested according to the relation of health and BMI level, were estimated. Results. The researches confirmed the accepted hypothesis about the negative influence of low and high fatness level, tested by BMI indexes, on the selected indexes of the positive health. The results of the concentration analysis and the Pearson’s correlation between BMI index and the physical efficiency’s elements tested referring to health show the reason to claim there are similar connections between the elements of the physical efficiency and the hierarchic structure in the group of individuals of low and high fatness. The statistically es-sential correlations only between efficiency’s morphologic components and BMI were found. Conclusion. The conducted researches confirmed: 1. The negative influence of too low and too high level of fatness on the level of the health positive indexes, 2. The statistically essen-tial correlation connections only between BMI and the somatic features which measure a body’s fatness, 3. The poor relations between BMI level and the positive health measures such as: physical efficiency, motor ability, 4. The similar structure of the physical efficiency tested referring to health in groups of lower and higher level of fatness.