Validation of anthropometric models in the estimation of appendicular lean soft tissue in young athletes

Pedro Pugliesi Abdalla,Ana Claudia Rossini Venturini,Thiago Cândido Alves,André Pereira Dos Santos,Anderson Dos Santos Carvalho,Analiza Mónica Silva,Dalmo Roberto Lopes Machado

doi:10.5007/1980-0037.2017v19n5p505

Pedro Pugliesi Abdalla, Ana Claudia Rossini Venturini + Show 5 more

Open Access

https://doi.org/10.5007/1980-0037.2017v19n5p505

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Abstract

Magnetic resonance imaging and computer tomography are gold standards in the measurement of muscle tissue (MT), but are expensive. Dual Energy X-Ray Absorptiometry (DXA) is also costly but safer and allows for the measurement of Appendicular Lean Soft Tissue (ALST), a strong predictor of MT. Alternatively, there are anthropometric models that predict the ALST of Portuguese athletes with low cost/risk that have not been validated in other populations. The aim of this study was to validate anthropometric Portuguese models that predict ALST in young athletes or, if the validation fails, to propose new models. The ALSTDXA of 174 young athletes was determined by DXA. Two anthropometric models (ALSTmod1 and ALSTmod2) measuring ALST among Portuguese athletes were tested. To validate the coefficient of determination, the difference (bias) and concordance correlation coefficient between predicted and actual values were computed. Finally, association between mean and difference of methods was verified. Validation failed and, for this reason, new multiple regression models were proposed and validated using PRESS statistics. The Portuguese models explained ~96% of the ALSTDXA variability. The difference between ALSTmod1 and ALSTDXA (-0.7kg) was less than that found for the ALSTmod2 and ALSTDXA (-2.3kg), with limits of agreement from 3.6 to -2.1 and from 6.1 to -1.5kg, respectively. The new models included three predictive equations for ALST. Only ASLTmod1 was valid; however, it was prone to bias, depending on the magnitude of ALST values. The newly proposed models present validity with greater concordance (r²PRESS=0.98), lower standard error of estimate (SEEPRESS [kg]=0.91) and more homogeneous predicted extreme values.

Highlights

Skeletal muscular tissue (MT) is essential for athletic performance[1,2], as it is the most abundant body tissue in non-obese individuals[1,3]
In the estimation of the variability of values measured by Dual Energy X-ray Absorptiometry (DXA), the Portuguese models (ALSTmod1and ALSTmod2) explained approximately 96.4% and 95.9% (r2), respectively, of the variability of the ALSTDXA of Brazilian athletes
One of the anthropometric models designed by Quiterio et al.[2] to predict Appendicular Lean Soft Tissue (ALST) was validated in a sample of young athletes (ASLTmod1)

Summary

Introduction

Skeletal muscular tissue (MT) is essential for athletic performance[1,2], as it is the most abundant body tissue in non-obese individuals[1,3]. The use of valid and applicable methods to quantify the MT of young athletes is highly relevant to monitoring the effects of athletic training on one’s MT structure, determining training loads in different phases and balancing training routines with dietary prescriptions, enabling the preservation of or increase in muscle mass to improve athletic performance[2]. Even though MT represents a large part of one’s body structure[4], measuring it in live individuals is a complex task when compared to other measures, such as fat or bone tissue. The study showed that these methods accurately quantify MT at the tissue level (IV). These methods are costly[2] and difficult to apply, while CT exposes individuals to radiation, which prevents applying it repetitively[7]

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