1. Abstract AIR DISPLACEMENT PLETHYSMOGRAPHY VERSUS DUAL ENERGY X-RAY ABSORPTIOMETRY FOR BODY COMPOSITION ASSESSMENT IN FEMALE ATHLETES Ronald L. Snarr 1, Jr., Henry N. Williford, FACSM 2, and Michael R. Esco, FACSM 2 1 School of Nutrition and Health Promotion, Arizona State University, Phoenix, AZ 2 Human Performance Laboratory, Auburn University at Montgomery, Montgomery, AL Methods Subjects Thirty female collegiate athletes (mean age = 21.87 ± 1.93, height = 167.65 ± 6.76 cm, weight = 65.21 ± 7.80 kg) volunteered for this study. For each athlete, BODPOD and DXA were used to measure BF% and FFM. The body composition measures were compared with T-tests, correlation procedures, and the method of Bland-Altman. Procedures For all participants, height measurements were taken with a digital wall stadiometer (Detecto, Missouri, USA). To obtain measures, all subjects stood erect, without shoes, and arms hanging by their sides against the stadiometer. Body composition was first tested using air displacement plethysmography (Bod Pod®, COSMED, Rome, Italy). For this measurement, subjects were required to wear a bathing suit and swim cap. Prior to body volume measurements, weight of the subject was measured via an external, electronic scale outside the Bod Pod® chamber. Once inside the chamber, subjects’ were asked to remain motionless and breathe normally as the body composition measurement, roughly 1-2 minutes, was completed. A whole-body DEXA scan (GE Lunar Prodigy®, Software version 10.50.086, GE Lunar Corporation, Madison, WI, USA) was used as the criterion method of BF% (BF%-DEXA). Calibration of the DEXA was performed before each scan according to the manufacturer’s specifications using the calibration block. Prior to each DEXA scan removal of all metal objects, such as jewelry, etc., was required by all subjects. Subjects were then instructed to lie completely motionless in the supine position with their arms down by their sides and hands in a neutral position. To avoid movement of their legs, the subjects’ ankles were held together by a Velcro strap. Introduction Assessing body composition in athletes is vital due to its potential impact on sports performance and overall health. Air displacement plethysmography (BODPOD) and dual energy x-ray absorptiometry (DXA) are two laboratory techniques of measuring body composition. Both methods are often utilized as criterion measures in sports science investigations. However, there is limited research comparing the BODPOD and DXA among female athletes. The purpose of this investigation was to compare BODPOD and DXA for estimating body fat percentage (BF%) and fat-free mass (FFM) in female athletes. Assessing body composition in athletes is vital due to its potential impact on sports performance and overall health. Air displacement plethysmography (BODPOD) and dual energy x-ray absorptiometry (DXA) are two laboratory techniques of measuring body composition. Both methods are often utilized as criterion measures in sports science investigations. However, there is limited research comparing the BODPOD and DXA among female athletes. PURPOSE: The purpose of this investigation was to compare BODPOD and DXA for estimating body fat percentage (BF%) and fat-free mass (FFM) in female athletes. METHODS: Thirty female collegiate athletes (mean age = 21.87 ± 1.93, height = 167.65 ± 6.76 cm, weight = 65.21 ± 7.80 kg) volunteered for this study. For each athlete, BODPOD and DXA were used to measure BF% and FFM. The body composition measures were compared with T-tests, correlation procedures, and the method of Bland-Altman. RESULTS: The mean BF% and FFM acquired from BODPOD was 22.4 ± 5.1% and 50.4 ± 5.2 kg, respectively, and from DXA was 27.4 ± 4.3% and 47.2 ± 5.2 kg, respectively. The BF% and FFM values were significantly different between DXA and BODPOD (p < 0.05) despite significant correlations (r = 0.85, p < 0.05 for BF% and r = 0.94, p < 0.05 for FFM). The limits of agreement showed that the 95% confidence interval of the mean difference (i.e., BODPOD – DXA) ranged from 0.3% to -10.3% for BF% and from 0.2 to -6.6 kg for FFM. CONCLUSION: This study demonstrated significant differences in BF% and FFM between BODPOD and DXA. Furthermore, the limits of agreement between the two techniques were wide. Future research is needed to determine accurate body composition assessment tools in female athletes. Conclusion This study demonstrated significant differences in BF% and FFM between BODPOD and DXA. Furthermore, the limits of agreement between the two techniques were wide. These results are in agreement with previous research of collegiate female track and field athletes, where BF% was significantly different (1). Therefore, future research is needed to determine accurate body composition assessment tools in female athletes. Results The mean BF% and FFM acquired from BODPOD was 22.4 ± 5.1% and 50.4 ± 5.2 kg, respectively, and from DXA was 27.4 ± 4.3% and 47.2 ± 5.2 kg, respectively. The BF% and FFM values were significantly different between DXA and BODPOD (p < 0.05) despite significant correlations (r = 0.85, p < 0.05 for BF% and r = 0.94, p < 0.05 for FFM). The limits of agreement showed that the 95% confidence interval of the mean difference (i.e., BODPOD – DXA) ranged from 0.3% to -10.3% for BF% and from 0.2 to -6.6 kg for FFM (Figures 1 and 2). References 1.Ball, SD, and Altena, TS. Comparison of the Bod Pod and dual energy x-ray absorptiometry in men. Physiol Meas 25(3): 671-678, 2004. 2.Ballard, TP, Fafara, L, and Vukovich, MD. Comparison of Bod Pod and DXA in female collegiate athletes. Med Sci Sports Exerc 36(4): 731-735, 2004. 3.Bentzur, KM, Kravitz, L, and Lockner, DW. Evaluation of the BOD POD for estimating percent body fat in collegiate track and field female athletes: a comparison of four methods. J Strength Cond Res 22(6): 1985-1991, 2008. 4.Peterson, JT, Repovich, WES, and Parascand, CR. Accuracy of consumer grade bioelectrical impedance analysis devices compared to air displacement plethysmography. Int J Exerc Sci. 176-184, 2011. Results