Aim of the thesis
The aim of the ”Physical Activity among Norwegian Children Study” was to perform a study that was aimed to describe physical activity, physical fitness and cardiovascular disease (CVD) risk factor levels in a nationally representative sample of 9- and 15-year-olds. The study was initialized and funded by the Norwegian Directorate of Health.  

 

A total of 2299 children and adolescents participated in the study. The participation rate was high; 89% among the 9-year-olds and 74% among the 15-year-olds. Physical activity was assessed objectively by accelerometry and aerobic fitness was measured directly through a maximum exercise test on a cycle ergometer. Muscle fitness was assessed by measuring explosive, isometric, and endurance strength and CVD risk factors were measured from fasting blood samples. The data collection started in March 2005 and was completed in October 2006.

 

Physical activity level
The results revealed that boys have a higher physical activity level than girls at both 9- and 15-years. Nine-year-olds had a physical activity level that was 46% higher than the 15-year-olds. Whilst four out of five children met current physical activity guidelines, only half of the adolescents did.

Physical  fitness
This study has also included measures of the participants’ physical fitness. Among 9-year-old mean values for peak oxygen uptake (ml •min-1• kg-1) were 48 for boys and 43 for girls, and 52 and 41 for 15-year old boys and girls, respectively. In both age groups, boys performed better on all muscle fitness measures than girls, exceptfor the Biering Sørensen test, where the 15-year old girls performed better than the 15-year old boys.

 

Risk factors for CVD
This study provides for the first time reference values on selected CVD risk factors in a nationally representative sample of Norwegian children and adolescents. This study gives an opportunety to examine the distibrution of CVD risk factors from a normal population.

 

Physical fitness and CVD risk factors
This study also examined the independent associations of muscle fitness and aerobic fitness and clustered CVD risk. The results revealed that both muscle fitness and aerobic fitness were independently associated with clustering of CVD risk factors. Moreover, the largest difference in CVD risk was observed between the two lowest quartiles of physical fitness.

 

Jostein Steene-Johannessen (14.12.1975) is born in Bærum. He obtained his Bachelors degree in physical activity and health from NSSS. He completed his Master’s degree in physical activity and health from NSSS. Jostein started his PhD in 2005, and has been supervised by Professor   Sigmund A. Anderssen and Professor Lars Bo Andersen.