Evaluation of a BMI Based Body Composition Equation in Intercollegiate Athletes

Abstract

INTRODUCTION: Assessment of body composition in collegiate athletes is an effective tool to enhance training and nutrition protocols. The use of Body Mass Index (BMI) based equations for such purposes has been found to be relatively invalid in athletes due to the inability to decipher between fat and fat-free mass. Recently, a BMI based equation developed by Nickerson et. al. (BMI_NICKERSON) that incorporates handgrip strength as a surrogate for lean mass was found to estimate body fat with low error in general population adults. The use of such a method in collegiate athletes may in turn provide a cost-effective and easily administered option for body composition assessment. PURPOSE: To compare the effectiveness of BMI_NICKERSON with traditional body composition methods in estimating body fat percentage of collegiate athletes. METHODS: Forty-one (n = 41) intercollegiate athletes (n = 21 male, 20 female) were assessed for percentage body fat using BMI_NICKERSON, bio-electrical impedance analysis (BIA) and seven site skinfold (SF). Pearson’s correlation was utilized to assess relationships among measurements methods. A sex x measurement method Two-Way ANOVA with repeated measures on the latter was utilized to determine potential differences in body fat percentage as estimated by each method between males and females. RESULTS: Good to excellent agreement was displayed between BIA and BMI_NICKERSON compared to SF in the total population and each sex (r > 0.76, p < 0.001). A significant interaction (F = 5.01, p = 0.01) between sex and measurement method was found for the sample. Paired samples t-testing in females revealed a significantly greater body fat estimation by BMI_NICKERSON (26.75 % ± 3.72 %) in comparison to both BIA (t = 7.73, p < 0.001, 22.36 % ± 2.80 %) and SF (t = 5.15, p < 0.001, 23.37 % ± 4.49 %). BIA and SF did not significantly differ (t = 1.51, p = 0.15) in females. Further paired samples t-testing in males revealed a significantly greater body fat estimation by BMI_NICKERSON (17.66 % ± 4.30 %) in comparison to both BIA (t = 8.74, p < 0.001, 13.15 % ± 4.28 %) and SF (t = 8.78, p < 0.001, 11.73 % ± 4.38 %). In addition, a significantly greater (t = 2.10, p = 0.05) body fat estimation was found using BIA in comparison to SF in males. CONCLUSION: Although the use of BMI_NICKERSON in estimating body composition has been shown to provide relatively accurate results in the general population, the current study did not observe the same in collegiate athletes. Further research comparing BMI_NICKERSON to a gold standard measurement technique in collegiate athletes is warranted.