title: Utility of novel body indices in predicting fat mass in elite athletes.
abstract: OBJECTIVE
  Recently, new body indices, including body adiposity (BAI), a body shape (ABSI), and body roundness (BRI) indices have been developed to estimate adiposity. The aim of this study was to compare percent fat mass (%FM) with novel indices in an elite athlete population.
  
  
  METHODS
  Using a cross-sectional design, %FM in 159 male and 50 female athletes using a four-component model was assessed. The %FM was compared with body mass index (BMI), BAI, ABSI, BRI, and with other %FM field methods (bioimpedance spectroscopy and skinfold prediction equation). These associations were determined using multilinear regression analysis, which resulted in predictive models of %FM in athletes. Cross-validation was performed using the prediction residual error sum of squares (PRESS) statistics method.
  
  
  RESULTS
  Although higher associations than other indices were observed, BRI still presented low coefficients of determination (men: R(2) = 0.36; women: R(2) = 0.25) when comparing with other field methods (R(2) range, 0.33-0.75). Using BAI as the independent variable, the R(2) was 0.07 for men and 0.14 for women. ABSI did not result in a significant association with %FM in women (R(2) = 0.05) while in men a significant association was found (R(2) = 0.22). The BMI model resulted in a R(2) = 0.20 for men and R(2) = 0.22 for women. Waist circumference and the sum of skinfolds were the anthropometric variables with the highest association with adiposity. New alternatives were presented with higher coefficients of determination (PRESS R(2) ranged from 0.47 to 0.71).
  
  
  CONCLUSIONS
  The newly developed body indices are limited in predicting %FM in elite athletes, particularly when compared with other commonly and readily available field methods like bioimpedance analysis or skinfold prediction models.
authors.affiliation: Exercise and Health Laboratory, CIPER, Faculdade de Motricidade Humana, Universidade de Lisboa, Lisbon, Portugal.
authors.forename: Diana A
authors.initials: DA
authors.lastname: Santos
authors.affiliation: Exercise and Health Laboratory, CIPER, Faculdade de Motricidade Humana, Universidade de Lisboa, Lisbon, Portugal. Electronic address: Lsardinha@fmh.ulisboa.pt.
authors.forename: Analiza M
authors.initials: AM
authors.lastname: Silva
authors.affiliation: Exercise and Health Laboratory, CIPER, Faculdade de Motricidade Humana, Universidade de Lisboa, Lisbon, Portugal.
authors.forename: Catarina N
authors.initials: CN
authors.lastname: Matias
authors.affiliation: Exercise and Health Laboratory, CIPER, Faculdade de Motricidade Humana, Universidade de Lisboa, Lisbon, Portugal.
authors.forename: João P
authors.initials: JP
authors.lastname: Magalhães
authors.affiliation: Faculty of Physical Education and Sport, Lusófona University, Lisbon, Portugal.
authors.forename: Cláudia S
authors.initials: CS
authors.lastname: Minderico
authors.affiliation: Center for Quantitative Obesity Research, Montclair State University, Montclair, New Jersey, USA.
authors.forename: Diana M
authors.initials: DM
authors.lastname: Thomas
authors.affiliation: Exercise and Health Laboratory, CIPER, Faculdade de Motricidade Humana, Universidade de Lisboa, Lisbon, Portugal.
authors.forename: Luís B
authors.initials: LB
authors.lastname: Sardinha
mesh_terms: D050154:Adiposity / Q000502:physiology*; D000328:Adult; D000886:Anthropometry / Q000379:methods*; D056352:Athletes; D001823:Body Composition / Q000502:physiology*; D001827:Body Height; D015992:Body Mass Index; D001835:Body Weight; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D008297:Male; D015999:Multivariate Analysis; D011237:Predictive Value of Tests; D012737:Sex Factors; D012885:Skinfold Thickness; D055105:Waist Circumference / Q000502:physiology; D055815:Young Adult
keywords: Adiposity; Athletes; Body adiposity index; Body mass index; Body roundness index; Multicomponent models