Master of Science (MS)
The purpose of this study was to test the hypothesis that self-reported physical activity (PA) levels quantified from the International Physical Activity Questionnaire (IPAQ) could be used to improve the prediction of percent body fat (%BF) measured by dual-energy X-ray absorptiometry (DXA) from body mass index (BMI), gender, and race in White and Black college students. A total of 278 students, aged 18 – 24 yr, volunteered to participate. There were 133 males (85 White and 48 Black) and 145 females (77 White and 68 Black). Total activity levels were quantified in MET-hours per week (MET-hrs•wk-1) using the IPAQ short form. Height and weight were measured and BMI values calculated (kg•m-2). Percent fat was assessed using DXA. Regression analysis was used to determine the impact of MET-hrs•wk-1 on the relationship between %BF and BMI, taking gender and race into account. The prediction sum of squares (PRESS) statistic was used to cross-validate the models. Mean (± SD) values were as follows: MET-hrs•wk-1 37.4 ± 21.9, %BF 24.5 ± 9.3%, and BMI 24.4 ± 4.1 kg•m-2. Percent body fat was significantly correlated with MET-hrs•wk-1 (r = -0.44, p < 0.0001) and BMI (r = 0.38, p < 0.0001). Stepwise regression analysis of a reduced model with BMI, gender and race produced an R2 value of 0.81 (root mean square error [RMSE] = 4.07). The full model with MET-hrs•wk-1 marginally improved the prediction of %BF (R2 = 0.83, RMSE = 3.87). When cross-validated, the corresponding PRESS statistic for the reduced and full model was 4.10 and 3.90, respectively. These results suggest that %BF can be predicted with greater precision and accuracy in a college-aged population when MET-hrs•wk-1 are included in addition to BMI, gender, and race.
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Zanovec, Michael, "The Impact of Self-Reported Physical Activity Levels on the Prediction of Body Fatness from BMI in White and Black College Students" (2008). LSU Master's Theses. 4003.