Ultrasound techniques applied to body fat measurement in male and female athletes.

CONTEXT For athletes in disciplines with weight categories, it is important to assess body composition and weight fluctuations. OBJECTIVE To evaluate the accuracy of measuring body fat percentage with a portable ultrasound device possessing high accuracy and reliability versus fan-beam, dual-energy X-ray absorptiometry (DEXA). DESIGN Cross-validation study. SETTING Research laboratory. PATIENTS OR OTHER PARTICIPANTS A total of 93 athletes (24 women, 69 men), aged 23.5 +/- 3.7 years, with body mass index = 24.0 +/- 4.2 and body fat percentage via DEXA = 9.41 +/- 8.1 participated. All participants were elite athletes selected from the Institut National des Sports et de l'Education Physique. These participants practiced a variety of weight-category sports. MAIN OUTCOME MEASURE(S) We measured body fat and body fat percentage using an ultrasound technique associated with anthropometric values and the DEXA reference technique. Cross-validation between the ultrasound technique and DEXA was then performed. RESULTS Ultrasound estimates of body fat percentage were correlated closely with those of DEXA in both females (r = 0.97, standard error of the estimate = 1.79) and males (r = 0.98, standard error of the estimate = 0.96). The ultrasound technique in both sexes had a low total error (0.93). The 95% limit of agreement was -0.06 +/- 1.2 for all athletes and did not show an overprediction or underprediction bias. We developed a new model to produce body fat estimates with ultrasound and anthropometric dimensions. CONCLUSIONS The limits of agreement with the ultrasound technique compared with DEXA measurements were very good. Consequently, the use of a portable ultrasound device produced accurate body fat and body fat percentage estimates in relation to the fan-beam DEXA technique.