# Bioelectrical Impedance Vector Analysis (BIVA) and Somatotype in Female Rugby Players
## 3 Results  
The sample was formed by 19 women with an average age of 24.7 years (SD: 5.9; range: 15.2 to 37.4). Considering the players positions in the field, eight subjects were forwards and eleven were backs. The mean BMI of the athletes was 26.03 kg/m2 (6.2) and was statistically significantly higher for the forwards (31.14 kg/m2 (6.1)) compared to the backs (22.32 kg/m2 (2.7)) (\(p=0.004\)). The BMI cut-off points of the WHO show that one player (back) was underweight, ten were normal weight (one forward and nine backs), four were overweight (three forwards and one back), and four forwards presented obesity. There were statistically significant differences between forwards and backs (\(p=0.007\)). Table 1 shows the anthropometric characteristics and BC measurements. Forwards presented a statistically significant higher FM and residual mass versus the backs. No statistically significant differences in SMM nor in bone mass were found. The FM% obtained by BIA was 26.5% (2.8): 28.7% (1.9) for forwards and 24.8% (2.1) for backs. This difference was statistically significant (\(p=0.001\)). The SMM estimated for the total sample was 24.14 kg (9.5): 24.8 kg (3.9) for forwards and 23.7 kg (2.5) for backs. This difference was not statistically significant (\(p=0.447\)). The agreement between BC estimation models, BIA and anthropometry, was also analysed. The results showed a moderate ICC for BIA-FM% ([PERSON] et al. 's equation) and anthropometry-FM% ([PERSON] and [PERSON]'s equation) (ICC 0.626 (CI 95%: 0.028-0.856; \(p=0.022\))). Agreement between SMM estimation models was excellent, with an ICC of 0.899 (CI 95%: 0.737-0.961; \(p<0.001\)) by using the [PERSON] (BIA) and [PERSON] (anthropometry) models. Somatotype components for the total sample and players' position are presented in Table 2. There were statistically significant differences between forward and back players for the values of ectomorphy, mesomorphy, and endomorphy. Endomorphy and mesomorphy values of forwards were much higher than the reference for Spanish rugby players [33]; however, the ectomorphy value was notably smaller. Endomorphy and ectomorphy values of backs were higher than the reference values, but the mesomorph component was lower. \begin{table}
\begin{tabular}{c c c c} \hline \hline \multirow{2}{*}{**Variables**} & **Total Sample** & \multicolumn{2}{c}{**Player’s Position**} \\  & **(\(n=19\))** & **Forwards (\(n=8\))** & **Backs (\(n=11\))** \\ \hline Height (cm) & 165.5 (7.8) & 161.9 (9.1) & 168.2 (5.7) \\ Body mass (kg) & 71.1 (17.0) & 82.2 (20.6) & 63.0 (7.3) * \\ FM\% & 24.2 (8.3) & 30.7 (7.5) & 19.4 (5.1) * \\ FM (kg) & 18.2 (10.3) & 26.1 (11.0) & 12.5 (4.7) * \\ BM (kg) & 9.5 (1.4) & 9.9 (1.8) & 9.2 (0.9) \\ RM (kg) & 14.9 (3.6) & 17.2 (4.3) & 13.2 (1.5) * \\ SMM Lee (kg) & 25.2 (4.0) & 27.3 (5.1) & 23.7 (2.1) \\ SMM\% Lee & 36.0 (3.5) & 33.8 (3.6) & 37.7 (2.3) * \\ \hline \hline \end{tabular} FM: fat mass; BM: bone mass; RM: residual mass; SMM: skeletal muscle mass. *\(p<0.05\).  
\end{table} 
Table 1: Anthropometric characteristics and BC measurements of rugby players (total sample and player’s position). Figure 1 represents somatochart of the players. Figure 1a displays the total sample and the player's position subgroups (forwards: blue dot and backs: orange dot). The total sample somatotype was catalogued as mesomorph endomorph, although there were major differences between somatotype components values of forwards and backs. Figure 1b shows the somatochart for each individual player. Table 3 shows the raw electrical values from BIA. There were statistically significant differences between subgroups for the values of R, Z, PA, and the BIVA standardised variables for height and transverse areas (specific BIVA): Rsp, Xcsp, and Zsp. The classic BIVA study showed an impedance individual vector distribution in the tolerance ellipses similar to the reference sports population (Figure 2). Figure 3 shows the specific BIVA analysis.