Similarly, ADP is also a two-compartment model where body composition analysis is performed using the BOD POD system (COSMED USA, Inc., Concord, CA, USA), which involves measuring body volume by air displacement. At the same time, the individual is seated in the chamber and calculating the body density, which is used to estimate FM (% and kg) and FFM (% and kg) (based on the Siri equation) [1; 7]. The accuracy of the BOD POD in determining body composition has been considered high, but some studies have shown that it overestimates body fat percentage in lean individuals [8; 9; 10]. In addition, testing conditions such as clothing worn during measurement and excessive facial or body hair may affect the accuracy of results [1]. BIA is a common method used to measure body composition in the general population because it is easily accessible, simple, and inexpensive [1]. However, the consistency of the results compared to other established techniques is important. In previous studies, the validity of BIA compared with ADP presented inconsistent results [11; 12; 13]. Results of research by [PERSON] et al. [11] have shown that sometimes there are clear differences between the results of body fat content measured using BIA and ADP. Some studies have shown that the average body fat measured by BIA was less than ADP, and the limits of agreement were wide [11; 12]. Modern BIA devices can also automatically estimate trunk circumferences, including waist circumference (WC) and waist-to-hip ratio (WHR). However, there is limited research validating BIA measurements against manual measurement values [14]. Simple anthropometric indicators such as WC, WHR, and waist-to-height ratio (WHtR) have been used to diagnose central obesity. Existing evidence suggests that central obesity is more strongly associated with cardiometabolic risk factors and chronic disease risk than overall obesity. Consequently, central obesity indices may provide a more accurate estimate of adiposity and may be more closely associated with mortality risk compared to body mass index (BMI) [15]. Current recommendations suggest confirming obesity either through direct measurement of %BF, if available, or via at least one anthropometric criterion (e.g., WC, WHR, or WHtR) alongside BMI, using validated methods and cut-off points tailored to age, sex, and ethnicity [16]. Additionally, analyzing body composition raw data is enhanced by calculating fat mass index (FMI; as FMheight2) and the fat-free mass index (FFMI; as FFMheight[2]), which eliminate the differences in \(\mathrm{\SIUnitSymbolMicro\%BF}\) related to body height [17]. However, these calculations require a comprehensive body composition assessment. However, because body composition assessment methods are based on different principles, the results of studies are inconsistent, possibly due to the different BIA devices and study populations. Therefore, the objectives of the study were: (i) to compare the agreement of the results of the body fat percentage from the air displacement plethysmography (ADP)--BOD POD and bioelectrical impedance analysis (BIA) method--InBody 770; and (ii) to compare the agreement of the central obesity risk classification in young adult healthy females and males using data from manual WC measurement and BIA analysis. ADP and manual measurement of WC were utilized as reference techniques to compare variables estimated from BIA (i.e., body composition values, WC, and WHR).