Trends and age-related changes of physical activity among Portuguese adolescent girls from 2002-2014: highlights from the health behavior in school-aged children study

Background: To examine the trends of moderate- to vigorous-intensity physical activity (MVPA) from 2002, 2006, 2010, and 2014 in a representative sample of Portuguese adolescent girls and to investigate MVPA changes during adolescence in surveys of each year and by generation. Methods: A nationally representative sample of 6018 girls between 11 and 13 years and 3838 girls between 15 and 17 years was drawn from the Health Behaviour in School-Aged Children surveys in 2002, 2006, 2010, and 2014. A questionnaire was used to collect data of MVPA. Data were assessed with analysis of variance, t test, chi square, and chi-square test for trend. Results: The percentage of 11- to 13-year-old girls reporting 60 minutes of daily MVPA was low and stable between 2002 (9.5%) and 2014 (11.1%) (P = .21), such as for girls aged 15-17 years (2002 = 5.6%, 2014 = 5%, P = .81). The percentage of girls reporting 60 minutes MVPA decreased significantly among age groups in all year surveys. A significant decrease in correlation with age across the same generation of adolescents was also found. Conclusion: This study points out that the prevalence of Portuguese girls meeting the PA guidelines is low, declines with age, and is stable from 2002-2014. Therefore, different strategies to prevent MVPA decline and promote MVPA are needed since childhood.