Validação da bioimpedância elétrica por multifrequência em atletas

Abstract

It is recognized the importance of assessing body composition in athletic populations. Therefore, it is necessary to use valid techniques for the determination of the main molecular components. Dual-energy X-ray absorptiometry (DXA) is a precise and valid method for assessing body composition. However, DXA is still not available at the clinical and field settings. Thus, it is important to use simple techniques such as electrical bioimpedance analysis (BIA) but few studies validated this technique specifically multifrequency BIA in body composition assessment in athletes. Therefore, the aim of this research is to test the validity of multifrequency BIA (Tanita, Model MC-180) in the determination of bone mineral content (BMC), lean soft tissue (LST) and fat mass (FM) in athletes. A total of 79 elite athletes (35 males) were assessed by DXA and BIA. Comparison of means, concordance coefficient correlation, multiple regression and Bland-Altman analysis were performed. Tanita explained 76%, 72%, 95% and 73% of the total variability observed from the reference method for FM (kg), FM (%), LST and BMC, respectively. The concordance coefficient correlation for MIGO presented a substantial strength of agreement of 0,927. However, relatively larger limits of agreement were found between BIA and DXA for the several body components. These findings reveal that the Tanita MC-180 is a valid alternative, particularly in the estimation of LST, in a group of athletes. However, due to the limits of agreement obtained in the determination of the body components this equipment presents a more limited validity in the estimation of individual body composition. Key Words: Athletes; Physical Assessment; Body Composition.