Abstract
Objective. To quantify energy expenditure of various lifestyle physical activities of obese, overweight, and normal-weight girls. Methods. In total, fifty-five girls participated in six activities: a treadmill walk at 4.0 km·hr−1, run, football throw, walk in open area, cycle, and riding a scooter. Intensities for all activities except the treadmill walk were self-selected. Energy expenditure was measured using the COSMED K4b2 portable metabolic system. Analyses of variance were used to compare the three groups (obese n=11, overweight n=16, and normal weight n=28) on relative (ml·kg−1·min−1 and ml·FFM−1·min−1), and absolute energy expenditure (kJ·min−1). Magnitudes of the mean differences were examined using Cohen's delta (ES). Results. Relative
(ml·FFM−1·min−1) was not significantly different (p>0.05) among the groups for any activity. Obese girls expended more energy (p<0.05) than normal-weight girls on all weight bearing activities. These differences were large (ES≥0.91). The differences in kJ·min−1 between the obese and normal weight groups for the bicycle and scooter activities were moderate to large (ES≥0.56), although not statistically significant. The overweight group expended more energy than the normal weight group and less energy than the obese group on all activities (ES=0.17 to 1.82), although these differences were generally not statistically significant. Conclusions. The oxygen costs of various activities are similar among obese, overweight, and normal-weight girls when expressed relative to fat-free mass. When engaging in self-selected levels of activity, obese girls have a higher absolute energy expenditure than normal-weight girls.