Weekend and weekday patterns of physical activity in overweight and normal-weight adolescent girls.

OBJECTIVE To describe the patterns (specifically comparing weekdays and weekends classified by intensities) of physical activity (PA) measured by accelerometry in adolescent girls. RESEARCH METHODS AND PROCEDURES Healthy sixth grade girls (n=1603), 11 to 12 years old, were randomly recruited from 36 schools participating in the Trial of Activity in Adolescent Girls. Age, ethnicity, socioeconomic status, weight, and height were taken. PA patterns were measured for 6 days using accelerometry. RESULTS Adolescent girls spend most of their time in sedentary (52% to 57% of the day) and light activity (40% to 45% of the day) on weekdays and weekends. In all girls, total PA comprised 44.5% of the day (41.7% light, 2.2% moderate, and 0.7% vigorous) with sedentary activity comprising 55.4%. Moderate-to-vigorous PA (MVPA) was higher (p<0.001) on weekdays than weekends in all girls, but MVPA was lower in at-risk of overweight+overweight girls (p<0.001) on both weekdays and weekends compared with normal-weight girls. DISCUSSION Adolescent girls are more active at moderate and vigorous intensities on weekdays than on weekends, and at-risk of overweight and those overweight spend less time engaging in MVPA than normal-weight girls.