To compare objectively measured physical activity in 11- and 15-year-old children who were born preterm with term-born controls and related physical activity measures to lung function measures.

We used data from the Avon Longitudinal Study of Parents and Children. We compared total physical activity, moderate-to-vigorous physical activity, and sedentary behavior between children born at 25-32, 33-34, 35-36, and 37-43 weeks' gestation at ages 11 and 15 years. At age 11 years, physical activity measures were correlated with lung spirometry recorded at age 7-9 years.

Valid physical activity data at age 11 years were available for 5025, 197, 57, and 48 children born at 37-43, 35-36, 33-34, and 25-32 weeks' gestation, respectively. At age 15 years, valid physical activity data were available for 1829, 62, 32, and 24 children born at 37-43, 35-36, 33-34, and 25-32 weeks' gestation. Boys were more physically active than girls at both ages. There were no differences in total physical activity, moderate-to-vigorous physical activity, or sedentary behavior in children between the different gestation groups. Physical activity at age 11 years did not correlate with spirometry measures at age 7-9 years.

Physical activity was similar for the different gestational groups and did not correlate with lung spirometry. Physical activity does not appear to be limited in preterm-born children despite lung function deficits noted in childhood.