| Summary |
It is estimated that 31.5% of children are overweight or at risk for overweight. Overweight children tend to be less active than nonoverweight weight children. To date, little research is available regarding energy expenditure of lifestyle activities in children. The purpose ofthis study was to quantify energy expenditure of various lifestyle physical activities ofoverweight, at risk for overweight, and nonoverweight weight girls. Fifty-five girls participated in six different lifestyle physical activities: treadmill walk at 2.5 mph, run, football throw, walk in open area, cycling, and riding a scooter. Intensities for all activities except the treadmill walk were self-selected. Oxygen consumption and energy expenditure were measured using the COSMED K4b portable metabolic system during all activities. One way independent groups analyses of variance with Bonferonni adjustments were used to compare the three groups (overweight± = 15, at risk n = 14, and nonoverweight weight n = 26) on each ofthe six activities. These analyses were conducted for two outcome variables: relative VO2 (ml[superior dot]FFM-¹[superior dot]min-¹) and absolute energy expenditure (kcal[superior dot]min-¹). Magnitudes ofthe mean differences were examined with Cohen's delta (ES). Relative VO2 was not significantly different (p > .05) among the groups for any activity. Overweight girls expended more (p < .05) absolute energy (kcal[superior dot]min-¹) than nonoverweight weight girls on all weight bearing activities (i.e.. walking, running, throwing a football). These differences were large (ES >0.94). The differences in absolute energy expenditure between the overweight and nonoverweight weight groups for the bicycle and scooter activities were moderate to large (ES [greater-than-or-equal]0.66), although not statistically significant. The at risk group expended more energy than the nonoverweight weight group and less energy than the overweight group on all activities (ES = 0.28 to 1.68), although these differences were generally not statistically significant. Estimated MET intensities for all activities were higher than estimates from the adult compendium ofphysical activities. In conclusion, the oxygen costs of various activities are similar among overweight, at risk, and nonoverweight weight girls when expressed relative to fat free mass. When engaging in self-selected levels of activity, overweight girls have a higher absolute energy expenditure than nonoverweight weight girls. These estimates of energy expenditure can contribute to the development of a compendium of physical activities for children. |
