## 2 Materials and Methods
### Statistical Analysis  
The sample size for the study group was initially estimated to be 199 participants using G*Power, version 3.1.9.7 software. The calculations assumed a small effect size (0.2), two dependent groups, and the difference between two dependent means (matched pairs), a statistical power of 0.8, and an alpha significance level of 0.05. The final effect size of the results obtained in the study is 0.374, and the test's statistical power is 0.8034. The normality of the distribution of continuous variables and their differences was tested using the Shapiro-Wilk test. Descriptive characteristics are displayed as means \(\pm\) the standard deviation (SD) for the total sample, both males and females. The mean values were compared with the Mann-Whitney test to describe the difference between females and males. If necessary, differences in the percentage distribution of the categorical variables were verified with the chi2 test with Yates' correction. Differences in the mean result of WC, WHR, WHtR, %BF, and %FFM assessed or calculated from two methods were evaluated using the Wilcoxon matched pair test (unnormal distribution) or t-student for repeated measurements. The Pearson's correlation coefficient (r) was also calculated. The r was evaluated according to the following thresholds: <0.1 (trivial), 0.1-0.3 (weak), 0.3-0.5 (moderate), 0.5-0.7 (strong), 0.7-0.9 (very strong) and 0.9-1.0 (almost perfect) [26]. As part of the accuracy evaluation, paired \(t\)-tests were performed to identify differences in BF%, WC, and WHR estimations between methods. Simple linear regression models were fitted, and the Coefficient of Determination (R\({}^{2}\)) and Standard Error of Estimates (SEE), Mean Absolute Percent Error (MAPE), and Root Mean Square Error (RMSE) were reported. The agreement between the ADP and BIA for %BF, WC manual, and WC from BIA; WHR calculated, and WHR from BIA was evaluated by the Bland-Altman plots [27; 28]. Bland-Altman plots showing systematic bias and the limits of agreement (LOA) for the two compared devices or measurements were created [28]. The Bland-Altman index (%) was calculated as the percentage of participants falling outside the LOA. LOA was calculated using \(\pm\)2 SD from the mean value of the dependent variable. Agreement between methods was considered when the mean value of the dependent variable was not different from zero according to a paired \(t\)-test (\(p>0.05\)). To ascertain whether this bias remained, regardless of \begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline
**FMI Class** & **Severe** & **Moderate** & **Mild** & \multirow{2}{*}{**Normal**} & \multirow{2}{*}{**Excess Fat**} & \multicolumn{3}{c}{**Obese**} \\ \cline{2-2}
**[kg/m\({}^{2}\)]** & & & & & & **Class I** & **Class II** & **Class III** \\ \hline Males & \textless{}2 & 2 to \textless{}2.3 & 2.3 to \textless{}3 & 3–6 & \textgreater{}6 to 9 & \textgreater{}9 to 12 & \textgreater{}12 to 15 & \textgreater{}15 \\ \hline Females & \textless{}3.5 & 3.5 to \textless{}4 & 4 to \textless{}5 & 5–9 & \textgreater{}9 to 13 & \textgreater{}13 to 17 & \textgreater{}17 to 21 & \textgreater{}21 \\ \hline \hline \end{tabular}
\end{table} 
Table 1: FMI classification according to [PERSON] et al. [25]. the results (independent variable), the homogeneity of the dependent variable was assessed by simple linear regression analysis using the \(p\)-value of the beta (\(\beta\)) parameter. Thus, homogeneity was considered at a \(p\)-value > 0.05 of the \(\beta\) parameter [29]. Good clinical agreement was interpreted as the Bland-Altman index, defined _a priori_ as the limits of maximum acceptable differences (expected limits of agreement), demonstrated when at least 95% of the differences were within \(\pm\)2 SD, which corresponds to an index value of 5% [30,31]. From a clinical point of view and from the assumption of the Bland-Altman method, only the clinician who uses the test results can decide whether the mean deviation and LOA are acceptable or not [31]. The above value was set for the measurements performed.