[Trends in vigorous physical activity versus physical inactivity among 11-15 year olds from 1988 to 2002]

The increasing prevalence of overweight and obesity among children and adolescents suggests a need to study the development in main predictors of obesity, like eating habits and physical activity. The objective was to describe self-reported vigorous physical activity versus physical inactivity among children and adolescents over a period of 14 years, 1988-2002.

The study population was the Health Behaviour in School-aged Children (HBSC) study among nationally representative samples of 11, 13 and 15 year old students in 1988, 1991, 1994, 1998, and 2002. The data collection used the standardised HBSC questionnaire which included items about vigorous physical activity (VPA) outside school hours per week. We defined physically inactivity as 0 hours of VPA per week and high activity as at least 7 hours of VPA per week.

The prevalence of high activity was higher among boys than girls and increased by age. The prevalence of physically inactive students increased from 1988 to 2002, especially among the 15 year olds. The proportion of students with high activity decreased from 1988 to 2002, especially among the 15 year olds.

A large proportion of children and adolescents do not comply with the national recommendations that children should be physically active at least 60 minutes per day. The physical activity level decreased from 1988 to 2002. There is a need for extraordinary efforts to increase physical activity among children and adolescents.