Comparison Between Self-Reported Athleticism and the Calculated Fit Index in Body Composition Assessment

A common commercially available handheld bioelectrical impedance analysis (BIA) device is routinely utilized to estimate an individual's percent body fat (%BF) in a variety of public forums. These commercial devices typically utilize one of two settings: normal or athlete, when calculating %BF. PURPOSE: To determine if a self-report of athletic status is a valid procedure for determining the mode of operation for the commercially available BIA. METHODS: One-hundred and fifty-five young and apparently healthy individuals (87 women, 68 men): age 21 + 2 years, prepared to have their %BF estimated using a common commercially available bioelectrical impedance analysis device. The subjects completed a physical activity inventory in order to determine the type, intensity, and duration of their activity. The subjects were also asked if they considered themselves to be an athlete. The subject's fit index was calculated based on the results of the physical activity inventory. A fit index of 60 equaled 'athlete'. RESULTS: For the total and females populations χ2(1,N=155)=27.78, p=0.000, χ2(1,n=87)=31.72, p=0.000, respectively, while the males χ2(1,n=68)=1.56, p=0.211. The method sensitivity values were 0.83, 0.81, and 0.86, respectively for the total population, males, and females. The method specificity values were 0.64, 0.36, and 0.82, respectively for the total population, males, and females. The positive predictive values were 0.91, 0.87, and 0.95, respectively for the total population, males, and females. The negative predictive values were 0.46, 0.27, and 0.58, respectively for the total population, males, and females. CONCLUSIONS: Female participants were more likely to correctly identify themselves as either an athlete or non-athlete. Male participants who were athletes were likely to correctly identify themselves as such, while non-athlete males tended to over identify themselves as athletes. Based on the results of this study, it appears that a self-report of athletic status is sufficient when selecting between the normal and athlete modes on the BIA when reported by females, but should be used with caution when applying the self-report method in order to select the appropriate mode of analysis for males.