## 4 Discussion  
This study aimed to evaluate the influence of age and maturation on anthropometric characteristics, somatotype, and BIVA patterns in elite youth basketball players and to propose new tolerance ellipses for basketball players. The considered traits showed an increasing trend with age and MS, except for the skinfold thicknesses and R. These differences confirmed that fat parameters decrease with age and maturation in elite adolescent players. PhA was influenced by age and maturation, based on studies on young athletes from other sports [20; 21; 22]. The distribution of somatotypes of the U12-19 players of the present study is homogeneous, mainly covering the area of the somatogram close to meso- and ectomorphy, with the majority being mesomorph-ectomorph, followed by ectomorphic mesomorph and mesomorphic ectomorph. As the main authors reported [14], our results represent somatic traits composed of wide prevalence of stature-related musculoskeletal robustness and slenderness, where both mesomorphy and ectomorphy were greater than endomorphy (fatness). No particular trend was detected with age and maturation. Considering the group as a whole, the mean somatotype of young players was characterized by the following code: 2.3-3.9-3.7, indicating that the average young player had an ectomorphic mesomorphic body. Few studies considered the somatotype of young basketball athletes, and our data agree with the somatotype of the young male basketball players studied by [PERSON] et al. [1] (2.12-3.75-4.17). In the same study, the authors reported that young competitors were more ectomorphic, while professional players were more mesomorphic (2.26-4.57-3.04). [PERSON] and colleagues observed that male basketball players are likely to display a mesomorph somatotype, but there are also professional players from top teams with mixed and balanced somatotypes [4]. Concerning to the BIVA approach, the 50%, 75%, and 95% confidence intervals allow total body water (TBW) and soft tissues (e.g., bone content and fat-free mass) to be evaluated within reference population-specific ranges. We observed a trend from the upper right towards the lower left, aimed at the 50 th percentile in the R-Xc graph, where the U17 and U19 groups were placed exactly in the ellipse's centre, showing a body composition  
Figure 4: (**A**) Relationship between PCA and somatotype components; (**B**) relationship between PCA plot with resistance (R), reactance (Xc), and Phase Angle (PhA) on a logarithmic scale: scatterplot with the regression line. akin to the athletic population. In addition, the athletes in the U13E, U14E, and U15 groups were plotted inside the tolerance ellipses, but not U12, 13 OT, and U14 OT. This highlights the importance of considering biological maturity when evaluating differences in growth patterns in young athletes. The BIVA vector reflects the changes in TBW and lean tissue. Therefore, younger athletes with an advanced MS showed body compositions similar to those of adult athletes. This is due to the increase in soft tissue and fluid, which is primarily related to somatic maturation. Our detection is in line with previous results, where body compositions of adolescent elite football players were analyzed in relation to maturation [22]. When younger categories were observed in U17-U19 tolerance ellipses, we observed a homogeneous trend from the upper right towards the lower left, where only early and elder players approach the centre. In synthesis, the mean vector displacement of early-maturing athletes indicates that, to achieve the body composition of the basketball player profile, an increase in TBW and intra/extra cellular water ratio is necessary, shortening the vector length and increasing the slope. To our knowledge, this is the first study that evaluates the changes in the BIVA patterns and body composition in relation to MS and chronological age in elite youth basketball players. Although the changes detected are in accordance with expected physiology, no specific comparisons can be made.