## 3 Results
### The Bivariate Analysis  
Firstly, as shown in Table 2, in the total elite athlete sample, the ICC calculated between both the CUN-BAE and BIA methods for estimating BF% was 0.91 (95% CI: 0.88; 0.93). With regard to age and sport discipline, the ICCs were higher for junior athletes (ICC 0.96; 95% CI: 0.95; 0.97) and strength-power athletes (ICC 0.92; 95% CI: 0.88; 0.94) while they were lower for both male and female athletes, endurance athletes, and athletes within the 19-33-year age range. Overall, conformity between both methods, namely the CUN-BAE and BIA, was detected. At the same time, the established consistency of the measurements obtained using the two methods did not necessarily lead to agreement. \begin{table}
\begin{tabular}{c c c c c} \hline \hline \multirow{2}{*}{**Variables**} & **Total Athletes** & **Male Athletes** & **Female Athletes** & \\  & **(\(n\) = 323)** & **(\(n\) = 234)** & **(\(n\) = 89)** & **\(p\)*** \\ \cline{2-5}  & & **Mean \(\pm\) SD** & & \\ \hline Age (in years) & 19.1 \(\pm\) 3.4 & 19.2 \(\pm\) 3.3 & 19.9 \(\pm\) 3.8 & 0.608 \\ Athletic experience (in years) & 7.9 \(\pm\) 3.7 & 8.0 \(\pm\) 3.9 & 7.6 \(\pm\) 3.8 & 0.545 \\ Training regimen (workouts a week) & 5.9 \(\pm\) 0.7 & 5.7 \(\pm\) 0.6 & 5.9 \(\pm\) 0.7 & 0.598 \\ Training regimen (workouts a day) & 1.7 \(\pm\) 0.5 & 1.6 \(\pm\) 0.4 & 1.5 \(\pm\) 0.6 & 0.089 \\ Duration of exercise (minutes in a day) & 186 \(\pm\) 62 & 178 \(\pm\) 63 & 171 \(\pm\) 54 & 0.498 \\ Anthropometry & & & & \\ Body weight (kg) & 72.2 \(\pm\) 14.9 & 76.1 \(\pm\) 14.5 & 61.9 \(\pm\) 10.5 & \textless{}0.001 \\ Standing height (cm) & 180 \(\pm\) 12 & 183 \(\pm\) 12 & 170 \(\pm\) 8 & \textless{}0.001 \\ BMI (kg/m\({}^{2}\)) & 22.1 \(\pm\) 2.8 & 22.5 \(\pm\) 2.9 & 21.3 \(\pm\) 2.4 & \textless{}0.001 \\ BIA & & & & \\ BF (kg) a & 13.6 \(\pm\) 5.7 & 13.2 \(\pm\) 5.9 & 14.6 \(\pm\) 5.1 & 0.038 \\ BF\% a & 18.4 \(\pm\) 5.3 & 16.7 \(\pm\) 4.7 & 22.9 \(\pm\) 4.2 & \textless{}0.001 \\ Fat-free mass (kg) a & 58.7 \(\pm\) 11.1 & 62.9 \(\pm\) 9.6 & 47.4 \(\pm\) 6.1 & \textless{}0.001 \\ Fat-free mass (\%) a & 81.5 \(\pm\) 5.4 & 83.2 \(\pm\) 4.6 & 76.9 \(\pm\) 4.2 & \textless{}0.001 \\ CUN-BAE & & & & \\ BF (kg) & 13.7 \(\pm\) 6.5 & 12.7 \(\pm\) 6.5 & 16.4 \(\pm\) 5.6 & \textless{}0.001 \\ BF\% & 18.7 \(\pm\) 6.6 & 15.9 \(\pm\) 5.1 & 25.9 \(\pm\) 4.3 & \textless{}0.001 \\ \hline \hline \end{tabular} BMI—body mass index; BIA—bioelectrical impedance analysis; BF—body fat; CUN-BAE—the body fat prediction equation; 95% CI—95% confidence interval; LB—lower bound; UB—upper bound; \(\text{a}\)—predicted using the manufacturer’s equation; \(\text{a}\)—the \(p\)-value was calculated for between-sex differences.  
\end{table} 
Table 1: Demographic and anthropometric data on high-performance athlete sample. \begin{table}
\begin{tabular}{c c c c c} \hline \hline \multirow{2}{*}{**Variables**} & **\(n\)** & **BF% by BIA** &
\begin{tabular}{c} **BF% by** \\ **CUN-BAE** \\ \end{tabular} & **ICC** & **95\% CI [LB; UB]** \\ \hline Total athletes & 323 & 18.4 \(\pm\) 5.3 & 18.7 \(\pm\) 6.6 & 0.91 & [0.88; 0.93] \\ Male athletes & 234 & 16.6 \(\pm\) 4.7 & 15.9 \(\pm\) 5.1 & 0.86 & [0.82; 0.90] \\ Female athletes & 89 & 23.0 \(\pm\) 4.2 & 25.9 \(\pm\) 4.3 & 0.83 & [0.81; 0.95] \\ Strength–power athletes & 130 & 18.3 \(\pm\) 6.1 & 18.5 \(\pm\) 7.5 & 0.92 & [0.88; 0.94] \\ Endurance athletes & 193 & 18.5 \(\pm\) 4.8 & 18.8 \(\pm\) 6.0 & 0.91 & [0.88; 0.93] \\ Junior athletes (aged \(\leq\) 18) & 181 & 18.0 \(\pm\) 0.6 & 18.0 \(\pm\) 0.7 & 0.96 & [0.95; 0.97] \\ Elite athletes (aged 19–33) & 142 & 19.0 \(\pm\) 4.4 & 19.6 \(\pm\) 6.1 & 0.80 & [0.72; 0.85] \\ \hline \hline \end{tabular}  
* Data are presented as means \(\pm\) SD. ICC—intraclass correlation coefficient; 95% CI—95% confidence interval; LB—lower bound; UB—upper bound; BIA—bioelectrical impedance analysis; BF—body fat; CUN-BAE—the body fat prediction equation.  
\end{table}