Physical activity and fitness among adolescents in Sweden with a 20-year trend perspective

To prevent chronic diseases such as cardiovascular disease and type-2 diabetes, it is important to avoid body fatness, to remain physically active and to maintain aerobic fitness. It is also important to maintain a certain level of muscular strength to be able to perform everyday tasks in adolescence and adulthood. Regular study of the secular trends (time-changes) in physical activity and fitness of the young can help in identifying how social and lifestyle changes can affect these factors. Also, studying the attitudes towards physical activity among various groups of young, could provide information for tailoring physical activity promotion programmes for contemporary children and adolescents. The aim of this study was to investigate physical activity and physical fitness among 16-year old adolescents in secondary school in 1995. Also, the aim was to study the secular trend (time trend from 1974 to 1995) in physical activity and fitness. A questionnaire assessing physical activity was completed by 93% (n=542) of the invited adolescents and body dimension measurments and physical capacity tests was performed by 78% (n= 460) of the invited adolescents in 1995. In 1974, 395 adolescents was invited and all participated. One third of the students in 1995 failed to achieve the recommended level of thirty minutes of moderate intensity physical activity per day day and 70% did not achieve sixty minutes per day. Students in practical programs were less physically active, and were also less physically fit compared to students in theoretical programs. The difference between the educational programs in physical activity level was associated to lower socio-economic status, lower percieved positive influence from parents to be physically active as well as lower percieved health among the students in practical programs. Fewer girls than boys participated in sports and were members in sports clubs. On average, the girls also were physically active at lower intensities than the boys. However, there was no difference between girls and boys in the time spent in overall physical activity, since many girls performed physical activities outside sports clubs. More adolescents were active in leisure-time sports in 1995 compared to 1974. The adolescents were also more interested in keep-fit activities in 1995 compared to 1974, which is important from a public health perspective, since these activities have the potential to be continued into adulthood. However, the overall lifestyle of adolescents might have become more sedentary in 1995 compared to 1974. The higher body weight, lower running performance and muscular endurance in 1995 compared with 1974 may be due to less overall daily physical activity among girls and boys. The lower muscular endurance could also be due to lack of specific muscle endurance training for instance in leisure-time physical activity and in physical education in school. The physical activity level among adolescents was assessed by a questionnaire and showed acceptable associations to the physical activity level assed by an activity diary and to aerobic fitness on a group level. The questionnaire could be a valuable tool in examining behavioural changes following health and physical fitness promotion programmes and for studying the secular trends in physical activity levels