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Accuracy of DXA in estimating body composition changes in elite athletes using a four compartment model as the
Diana A Santos1, Analiza M Silva, Catarina N Matias
1Exercise and Health Laboratory, Faculty of Human Movement-Technical University of Lisbon, Portugal. analiza@fmh.utl.pt.
Nutrition & Metabolism
|March 24, 2010
Summary
Dual-energy x-ray absorptiometry (DXA) showed limited accuracy in tracking body composition changes, including relative fat mass, absolute fat mass, and fat-free mass, in elite male judo athletes. Further validation is needed for DXA in this population.
Area of Science:
- Sports Science
- Human Physiology
- Biomedical Engineering
Background:
- Dual-energy x-ray absorptiometry (DXA) is a common tool for body composition analysis.
- Limited data exists on DXA's ability to track body composition changes in elite athletes.
- Elite athletes undergo significant body composition fluctuations, especially during training and competition periods.
Purpose of the Study:
- To evaluate the accuracy of DXA in tracking changes in body composition among elite male judo athletes.
- To compare DXA-derived body composition changes against a criterion four-compartment (4C) model.
- To assess DXA's reliability in monitoring relative fat mass (%FM), absolute fat mass (FM), and fat-free mass (FFM) during periods of weight stability to pre-competition.
Main Methods:
- Twenty-seven elite male judo athletes participated in the study.
- Body composition was assessed using DXA and a 4C model incorporating air displacement plethysmography, DXA-derived bone mineral content, and deuterium dilution for total-body water.
- Statistical analyses included regression, coefficient of determination (r2), standard error of estimation (SEE), and Bland-Altman agreement analysis.
Main Results:
- At a group level, DXA changes in %FM, FM, and FFM were not significantly different from the 4C model.
- However, DXA changes explained only 29% (%FM), 36% (FM), and 38% (FFM) of the 4C model's reference values.
- Individual analysis revealed wide limits of agreement and a trend of DXA over/underestimating FM changes at the extremes.
Conclusions:
- DXA demonstrated insufficient accuracy for tracking individual body composition changes in elite male judo athletes.
- The findings suggest caution when using DXA for monitoring adiposity fluctuations in this specific athletic population.
- Further research is recommended to improve DXA's precision or explore alternative methods for elite athlete body composition tracking.
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