Methods over Materials: The Need for Sport-Specific Equations to Accurately Predict Fat Mass Using Bioimpedance Analysis or Anthropometry

Abstract

Bioelectrical impedance analysis (BIA) and anthropometry are considered alternatives to well-established reference techniques for assessing body composition. In team sports, the percentage of fat mass (FM%) is one of the most informative parameters, and a wide range of predictive equations allow for its estimation through both BIA and anthropometry. Although it is not clear which of these two techniques is more accurate for estimating FM%, the choice of the predictive equation could be a determining factor. The present study aimed to examine the validity of BIA and anthropometry in estimating FM% with different predictive equations, using dual X-ray absorptiometry (DXA) as a reference, in a group of futsal players. A total of 67 high-level male futsal players (age 23.7 ± 5.4 years) underwent BIA, anthropometric measurements, and DXA scanning. Four generalized, four athletic, and two sport-specific predictive equations were used for estimating FM% from raw bioelectric and anthropometric parameters. DXA-derived FM% was used as a reference. BIA-based generalized equations overestimated FM% (ranging from 1.13 to 2.69%, p < 0.05), whereas anthropometry-based generalized equations underestimated FM% in the futsal players (ranging from −1.72 to −2.04%, p < 0.05). Compared to DXA, no mean bias (p > 0.05) was observed using the athletic and sport-specific equations. Sport-specific equations allowed for more accurate and precise FM% estimations than did athletic predictive equations, with no trend (ranging from r = −0.217 to 0.235, p > 0.05). Regardless of the instrument, the choice of the equation determines the validity in FM% prediction. In conclusion, BIA and anthropometry can be used interchangeably, allowing for valid FM% estimations, provided that athletic and sport-specific equations are applied.

ISAK-Based Anthropometric Standards for Elite Male and Female Soccer Players

“…Generally, various tools are used to estimate components related to fat or muscle mass, differing in cost and accuracy [ 28 ]. However, when assessing body composition, it is crucial to acknowledge that different assessment methods may yield disparate estimates, irrespective of the considered body mass component [ 29 ]. In the context of soccer, the application of various equations and methods often leads to a variation in fat mass values, ranging from 11% to 14% [ 27 , 28 , 29 , 30 ].…”

“…However, when assessing body composition, it is crucial to acknowledge that different assessment methods may yield disparate estimates, irrespective of the considered body mass component [ 29 ]. In the context of soccer, the application of various equations and methods often leads to a variation in fat mass values, ranging from 11% to 14% [ 27 , 28 , 29 , 30 ]. This variability in the procedures employed makes it challenging and not always reliable to compare values from different studies.…”

“…This variability in the procedures employed makes it challenging and not always reliable to compare values from different studies. Recent research prefers to provide reference parameters for raw measurements to avoid artifacts stemming from theoretical assumptions about body composition or estimation errors due to predictive models, especially in athletes [ 29 , 30 , 31 , 32 ]. Moreover, given that laboratory techniques may not always be available, having low-cost and time-efficient tools, such as anthropometry, is essential for practitioners and researchers interested in field evaluations.…”

Comparisons and associations among anthropometric indices of first and second division and assistant soccer referees

“…Despite the robustness of the present findings, this cross-sectional study had some limitations such as the fact that it was not possible to determine cause-and-effect relationships. Moreover, body composition was assessed through non-considered reference methods but, according to a recent study, anthropometry can also be used for valid FM% estimations (Campa et al, 2023 ). In addition, nutritional habits (Sarkar et al, 2019 ; Afrifa et al, 2020 ) could probably help justify why assistant referees tended to have higher values.…”

Localized hamstring bioimpedance in marathon runners is related to muscle high-energy enzyme serum levels and predicts race time

“…In sports, whole-body and L-BIA measurements have been applied as evaluation methods for body composition analysis and muscle assessment, respectively. Whole-body BIA in sports has been used to analyze nutritional status and soft tissue composition ( Micheli et al, 2014 ), quantitative body composition ( Campa et al, 2023 ), aerobic fitness ( Matias et al, 2022 ), training effectiveness, performance levels ( Di Vincenzo et al, 2020 ; López-Fernández et al, 2020 ; Marra et al, 2020 ), and even talent identification ( López-Fernández et al, 2020 ; Marra et al, 2020 ). Consistently, whole-body BIA increases in R, Xc, and PhA have been reported ( Castizo-Olier et al, 2018 ) after different types of sports and physical exercise intensity.…”