## 2 Materials and Methods
### Air Displacement Plethysmography (ADP)  
BOD POD (COSMED USA, Inc., Concord, CA, USA) was used for ADP. System quality checks and scale calibrations were carried out on a daily basis in accordance with the manufacturer's guidelines. TGV was predicted by the BOD POD system using OMNIA, version 2.3.0.6 software based on age, sex, and height.  
Plethysmography determines body volume (V_raw_) based on the pressure/volume relationship based on [PERSON]'s law (isothermal condition) and [PERSON]'s law (adiabatic condition). Body volume measurements in BOD POD take place primarily under adiabatic conditions. There is a certain volume of air maintained under isothermal conditions, as contained in the lungs, near the skin or hair, and in clothing [2; 24]. The average amount of air in the lungs during normal tidal breathing, as well as the volume of thoracic gas (VTG), can be measured or predicted. Thoracic gas volume (TGV) can be quantified as an additional measure while in the chamber or estimated by the BOD POD. The effect of isothermal air near the skin surface is estimated by computing the area artifact (SAA). SAA is automatically calculated by the BOD POD software as follows:  
\[\text{SAA (L)}=k\ \text{(L/cm${}^{2}$)}\ \times\ \text{BSA (cm${}^{2}$)},\]  
where \(k\) is a constant (derived empirically by the manufacturer; and BSA is the body surface area. BSA is calculated from the body mass and height using the DuBois formula. The SAA is typically 1.0 L for average-sized adults [2]. Then, the body volume is calculated using the formula:  
\[\text{V}_{\text{B (L)}}=\text{V}\textit{raw (L)}-\text{SAA (L)}+40\%\ \text{TGV (L)},\]  
where \(\text{V}_{\text{B}}\) is the body volume corrected for SAA and TGV. As part of the test procedure, the subject is also weighed; hence, the body density (D) can be calculated as \(\text{M}/\text{V}_{\text{B}}\). Then, the %BF is estimated based on the Siri model or Brozek equation [24].  
The ADP examination was performed under standardized conditions, according to the manufacturer's protocol. Participants were instructed to wear form-fitting clothing,such as a swimsuit or single-layer compression shorts, and a single-layer sports bra for females. Hair was thoroughly compressed by a swim cap.  
The measurement included two assessments of the participant's raw body volume, but if these differed by more than 150 mL, the BOD POD software instructed to perform a third assessment and used the mean of the two closest values in subsequent computations. If no two measurements met the acceptance criteria, the entire trial was repeated. Repeated measurements in five healthy males and females had an intraclass correlation R of 0.98 and a standard deviation of 0.005 g/cm\({}^{3}\) for body density. %BF and FFM were computed using the Siri equation using the BOD POD software. Further analysis included the FM and %BF.  
Further analysis also included the FM results from ADP and BIA. On this basis, the FMI was also calculated as FM (kg) divided by H (m\({}^{2}\)) [17]. Moreover, to classify the participants according to their body fat content, the values proposed by [PERSON] et al. were used, presented in Table 1[25].