To determine whether directly measured physical activity and sedentary behavior patterns of obese children presenting to a weight-management clinic differs from nationally representative samples of obese and normal-weight children.

A cross-sectional comparison study of 3 groups of boys and girls between 8 and 18 years (mean, 13.4 years) was performed. A clinical group (n = 56) seeking specialized care for obesity was compared with 2 nationally representative samples of children from the Canadian Health Measures Survey (CHMS): (1) body mass index >95th percentile (n = 143); and (2) body mass index <85th percentile (n = 958).

Obese clinical and obese CHMS boys did not differ in daily moderate-to-vigorous physical activity (MVPA). Both obese groups engaged in less MVPA than normal-weight boys in the CHMS (P < .0006). Compared with normal-weight boys, obese boys had fewer days in which they accrued 60 or 30 minutes of MVPA (P = .006 and .01, respectively). Daily MVPA did not differ among the 3 groups of girls. Light activity in clinical boys was lower than in the normal weight CHMS boys, whereas clinical girls engaged in less light activity than both CHMS comparators. No differences were observed between groups for sedentary behavior.

Obese youth, whether in clinic or the community, were not more sedentary than their normal-weight CHMS comparators. Although obese youth were less active, overall MVPA was low in all groups. This finding highlights the need for health professionals to target both physical activity and sedentary behavior in all children, rather than focusing on only children with obesity.