Energy expenditure of obese, overweight, and normal weight females during lifestyle physical activities

To quantify energy expenditure of various lifestyle physical activities of obese, overweight, and normal-weight girls. 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 ./SPOB_A_287654_O_XML_IMAGES/SPOB_A_287654_O_ILM0001.gif (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). Relative ./SPOB_A_287654_O_XML_IMAGES/SPOB_A_287654_O_ILM0002.gif (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. 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.