# Anthropometric Characteristics and Somatotype of Young Slovenian Tennis Players
## 3 Results  
Descriptive statistics, including mean, standard deviation, and range, are presented for anthropometric variables in four age categories (under 12, under 14, under 16, and under 18) separately for boys and girls (Table 2). As expected, the values for the longitudinal, transverse, and circumferential measurements increase with age, while the changes in skinfolds vary according to gender and measurement location on the body. Significant differences in body height, body mass, and BMI were observed across all age categories, from U12 to U18 (all \(p<0.001\)). Among skinfold measurements, the suprailiac, abdominal (except U16 vs. U18, \(p=0.137\)), and subscapular sites showed significant differences in nearly all pairwise comparisons (\(p<0.05\)), reflecting age-related changes in fat distribution. Calf skinfold thickness was significantly different in selected comparisons (e.g., U14 vs. U16, U14 vs. U18, and U12 vs. U18), while thigh and forearm skinfolds showed significant differences primarily between the youngest and oldest groups (U12 vs. U18 and U14 vs. U18, \(p<0.05\)). In contrast, triceps, biceps, and chest skinfolds did not show significant age-related changes (all \(p>0.05\)). Age-related increases were also observed in upper arm, thigh, calf, and chest girths, with all comparisons showing strong statistical significance (\(p<0.001\)). Similarly, both leg and arm lengths increased consistently with age (\(p<0.001\)). However, no significant differences were found in humoral, femoral, or bimalleolar breadths between older categories (e.g., U16 vs. U18, \(p>0.05\)). Significant sex differences were observed in body height across all categories except U14 (U14: \(p=0.053\); U12, U16 and U18: \(p<0.001\)). Body mass showed significant differences from U14 onward (U14: \(p<0.05\); U16 and U18: \(p<0.001\)), while body mass index differed significantly only in U14 and U16 (\(p<0.05\)). Skinfold thickness measurements at the calf, thigh, suprailiac, abdominal, subscapular, tricep, and bicep sites showed significant differences between sexes across all age groups (\(p<0.001\)), except forearm skinfold, which was significant from under 14 onward (\(p<0.001\)) and not in the youngest group (\(p=0.1966\)). Chest skinfold differences were significant from under 14 (\(p<0.001\)) onward but not in the under 12 group. Upper arm girth was significantly different starting at under 14 (\(p<0.05\)), while maximum upper arm girth differences were significant only in the under 16 and under 18 groups (\(p<0.001\)). Thigh and calf girths showed significant sex differences, especially in the older groups (\(p<0.05\)). Bone breadths (humerus, femur, and bimalleolar) and limb lengths showed significant sex differences, especially in the under 16 and under 18 categories (\(p<0.001\)). Clear differences in somatotype components were found between the age categories in both boys and girls (Figure 1). In boys, endomorphy decreased with age, with significant differences between U12 and U16 (\(p<0.001\)) and an increase between U16 and U18 (\(p<0.05\)). A different trend was observed in girls, where endomorphy was higher at U16 and U18 than at U12 (\(p<0.01\) and \(p<0.05\), respectively). Mesomorphy decreased significantly from U12 to U14 in both genders (boys: \(p<0.001\); girls: \(p<0.001\)) and remained relatively stable in the older groups. Further significant changes were observed between U12 and U16 in boys (\(p<0.001\)) and girls (\(p<0.01\)). Electomorphy was significantly greater in younger age groups compared to older ones. In boys, U12, U14, and U16 did not differ significantly, but U18 showed significantly lower values (\(p<0.05\)). In girls, a significant decline was observed across age, with U12 and U14 showing higher ectomorphy than U16, and U18 showing the lowest values (all \(p<0.05\)).