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.