Body composition assessment in athletes: Comparison of a novel ultrasound technique to traditional skinfold measures and criterion DXA measure

Objectives: This investigation compared ultrasound and skinfolds as measures of body fat for athletes, relative to dual-energy X-ray absorptiometry. Design: Fifty-six well-trained athletes from various sports participated in a cross-sectional study. Methods: The participants attended one testing session, where total body fat mass was measured using dual-energy X-ray absorptiometry, and subcutaneous adipose tissue was measured using brightness-mode ultrasound and skinfolds with callipers. The ultrasound and skinfold measures were correlated independently against standardised fat mass from dual-energy X-ray absorptiometry. Results: The correlation between standardised fat mass and sum-of-eight (Σ8) sites ultrasound (r = 0.959, p < 0.001), and with sum-of-seven (Σ7) sites skinfolds (r = 0.911, p < 0.001), were both high positive correlations. In the lowest quartile by fat proportion, the correlation between standardised fat mass and Σ8 ultrasound (r = 0.811, p < 0.001) was a high positive correlation, whilst the correlation with Σ7 skinfolds (r = 0.652, p = 0.011) was a moderate positive correlation. In the highest quartile by fat proportion, the correlation between standardised fat mass and Σ8 ultrasound (r = 0.847, p < 0.001) was a high positive correlation, whilst the correlation with Σ7 skinfolds (r = 0.591, p = 0.026) was a moderate positive correlation. Conclusions: Ultrasound and skinfolds are both very good methods to accurately assess body composition in athletes, relative to dual-energy X-ray absorptiometry. However, ultrasound delivered consistently more accurate results, throughout a broad athletic spectrum.