Tracking changes in body composition: Comparison of methods and influence of pre-assessment standardization

Grant M. Tinsley, Patrick S. Harty, Matthew T. Stratton, Robert W. Smith, Christian Rodriguez, Madelin R. Siedler

Research output: Contribution to journalArticlepeer-review

Abstract

The present study reports the validity of multiple assessment methods for tracking changes in body composition over time and quantifies the influence of unstandardized pre-assessment procedures. Resistance-trained males underwent 6 weeks of structured resistance training alongside a hypercaloric diet, with four total body composition evaluations. Pre-intervention, body composition was estimated in standardized (i.e., overnight fasted and rested) and unstandardized (i.e., no control over pre-assessment activities) conditions within a single day. The same assessments were repeated post-intervention, and body composition changes were estimated from all possible combinations of pre-intervention and post-intervention data. Assessment methods included dual-energy X-ray absorptiometry (DXA), air displacement plethysmography, 3-dimensional optical imaging, single- and multi-frequency bioelectrical impedance analysis, bioimpedance spectroscopy, and multi-component models. Data were analyzed using equivalence testing, Bland-Altman analysis, Friedman tests, and validity metrics. Most methods demonstrated meaningful errors when unstandardized conditions were present pre- and/or post-intervention, resulting in blunted or exaggerated changes relative to true body composition changes. However, some methods – particularly DXA and select digital anthropometry techniques – were more robust to a lack of standardization. In standardized conditions, methods exhibiting the highest overall agreement with the 4-component model were other multi-component models, select bioimpedance technologies, DXA, and select digital anthropometry techniques. Although specific methods varied, the present study broadly demonstrates the importance of controlling and documenting standardization procedures prior to body composition assessments across distinct assessment technologies, particularly for longitudinal investigations. Additionally, there are meaningful differences in the ability of common methods to track longitudinal body composition changes.

Original languageEnglish
JournalBritish Journal of Nutrition
DOIs
StateAccepted/In press - 2021

Keywords

  • 3D scanning
  • 4-compartment model
  • Anthropometry
  • Bioimpedance
  • Body fat
  • Body fat percentage
  • DXA
  • Fat mass
  • Fat-free mass

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