Estimation of body fat in female collegiate dancers via BMI-based equations and air displacement plethysmography

Abstract

This study was conducted to evaluate the efficacy of three body mass index (BMI) based equations (BEQ) used to estimate body-fat percentage (BF%) in female-collegiate dancers in relation to air-displacement plethysmography (AP). Methods: Data from 28 collegiate dancers were assessed for this study. Body mass and height were measured to calculate BMI. Three BEQ to estimate BF% [Jackson et al. (JBMI), Deurenberg et al. (DBMI), and Womersley & Durnin (WBMI)] were compared to BF% estimated via AP. Results: The following estimates of BF% were produced: AP = 24.6 ± 4.7%; JBMI = 21.9 ± 4.0%; DBMI = 23.8 ± 2.2%; and WBMI = 24.7 ± 2.5%. There were no differences (p > 0.05) for the BF% estimations between AP, DBMI, or WBMI. However, BF% estimated via JBMI was lower than AP (p = 0.04), DBMI (p < 0.001), and WBMI (p < 0.001). Only moderate correlations were found between AP and BEQ (JBMI, r = 0.43; DBMI, r = 0.44; WBMI, r = 0.43). The limits of agreement (constant error ± 1.96 SD) for each BEQ compared to AP were: JBMI = -2.6 ­­± 9.1%; DBMI = -0.8 ­­± 8.1%; and WBMI = 0.2 ± 8.2%. Conclusions: Two BEQ produced similar group means to AP. However, all BEQ had a wide range of individual differences when compared to AP. An accurate, inexpensive, and practically feasible method of assessing body composition is valuable for sport practitioners. The results of this study demonstrate that DBMI and WBMI may be acceptable in a field setting for estimating BF% for a large group of female collegiate dancers. However, due to the large range of differences, none of the BMI-based equations should be utilized to predict BF% for individuals. It is suggested that other field methods of predicting BF% be used in female collegiate dancers due to individual error of BEQs and potential harm in providing misinformation. Key Words: air-displacement, body mass index, percent fat, dancers