Body composition in sport: a comparison of a novel ultrasound imaging technique to measure subcutaneous fat tissue compared with skinfold measurement
- Wolfram Müller1,
- Martin Horn1,
- Alfred Fürhapter-Rieger1,
- Philipp Kainz1,
- Julia M Kröpfl1,
- Ronald J Maughan2,
- Helmut Ahammer1
- 1Institute of Biophysics, Medical University of Graz, Graz, Austria
- 2Department of Exercise and Health Sciences, School of Sport, Loughborough University, Loughborough, UK
- Correspondence to Professor Wolfram Müller, Institute of Biophysics, Medical University of Graz, Harrachgasse 21/4, Graz 8010, Austria;
- Accepted 21 August 2013
- Published Online First 20 September 2013
Background Extremely low weight and rapid changes in weight and body composition have become major concerns in many sports, but sufficiently accurate field methods for body composition assessment in athletes are missing. This study aimed to explore the use of ultrasound methods for assessment of body fat content in athletes.
Methods 19 female athletes (stature: 1.67(±0.06) m, weight: 59.6(±7.6) kg; age: 19.5(±3.3) years) were investigated by three observers using a novel ultrasound method for thickness measurement of uncompressed subcutaneous adipose tissue and of embedded structures. Two observers also measured skinfold thickness at eight International Society for the Advancement of Kinanthrometry (ISAK) sites; mean skinfold values were compared to mean subcutaneous adipose tissue thicknesses measured by ultrasound. Interobserver reliability of imaging and evaluation obtained by this ultrasound technique: intraclass correlation coefficient ICC=0.968 (95% CI 0.957 to 0.977); evaluation of given images: ICC=0.997 (0.993 to 0.999).
Results Skinfold compared to ultrasound thickness showed that compressibility of subcutaneous adipose tissue depends largely on the site and the person: regression slopes ranged from 0.61 (biceps) to 1.59 (thigh) and CIs were large. Limits of agreement ranged from 2.6 to 8.6 mm. Regression lines did not intercept the skinfold axis at zero because of the skin thickness being included in the skinfold. The four ISAK trunk sites caused ultrasound imaging problems in 13 of 152 sites (8 ISAK sites, 19 athletes).
Conclusions The ultrasound method allows measurement of uncompressed subcutaneous adipose tissue thickness with an accuracy of 0.1–0.5 mm, depending on the probe frequency. Compressibility of the skinfold depends on the anatomical site, and skin thickness varies by a factor of two. This inevitably limits the skinfold methods for body fat estimation. Ultrasound accuracy for subcutaneous adipose tissue measurement is limited by the plasticity of fat and furrowed tissue borders. Comparative US measurements show that skinfold measurements do not allow accurate assessment of subcutaneous adipose tissue thickness.