Correlates of individual differences in body-composition changes resultingfrom physical training in obese children

Background: No studies have been reported in children that assess correlate s of body-composition changes in response to a physical training interventi on. Objective: The hypothesis studied was that variation in diet and physical a ctivity would explain a significant portion of the interindividual variatio n in the response of body composition to physical training. Design: The participants were 71 obese children aged 7-11 y (22 boys, 49 gi rls; 31 whites, 40 blacks). Body composition was measured by dual-energy X- ray absorptiometry, physical activity by a 7-d recall interview, and diet b y two, 2-d recalls. The children underwent 4 mo of physical training. Results: The mean attendance was 4 d/wk, the mean (+/-SD) heart rate for th e 40-min sessions was 157 +/- 7 beats/min, and the mean energy expenditure was 946 +/- 201 kJ/session. On average, the percentage body fat decreased s ignificantly in the total group, and total mass, fat-free soft tissue, bone mineral content, and bone mineral density increased, but there was a good deal of individual variability. Multiple regression models indicated that i n general, more frequent attendance, being a boy, lower energy intake, and more vigorous activity were associated with healthier body-composition chan ges with physical training. Ethnicity was not retained as a correlate of th e change of any component of body composition. Conclusions: In obese children, age, vigorous activity, diet, and baseline percentage body fat together accounted for 25% of the variance in the chang e in percentage body fat with physical training.