Agreement between B-Mode Ultrasound and Air Displacement Plethysmography in Preprofessional Ballet Dancers.

Purpose: This study aimed to assess the agreement between B-mode ultrasound and air displacement plethysmography (ADP) body composition results in preprofessional ballet dancers.

Methods: Male (n = 21, Mage = 17.2 ± 1.7 yr, MBMI = 20.5 ± 2.0 kg·m-2) and female (n = 27, Mage = 16.1 ± 1.4 yr, MBMI = 18.3 ± 1.3 kg·m-2) dancers were assessed by ADP and ultrasound to determine body fat percentage (%BF), fat mass (FM), and fat-free mass (FFM). Pearson's correlations were used to assess agreement, and paired t-tests were used to determine differences between devices (α = 0.05). Ultrasound validity was assessed using SEE and total error. Bland-Altman plots were used to identify 95% limits of agreement.

Results: Agreement was high for %BF (females, r = 0.94; males, r = 0.77), FM (females, r = 0.94; males, r = 0.73), and FFM (females, r = 0.95; males, r = 0.99). However, ultrasound overestimated %BF and FM and underestimated FFM (P < 0.05) compared with ADP in females only. In addition, there were stronger agreement and lower error for FFM compared with both %BF and FM regardless of sex.

Conclusion: There is strong agreement between ultrasound and ADP in this population. Although ultrasound may be a useful field tool to assess body composition, future research is needed to refine %BF equations in this population to reduce calculation errors.