Question naires were the more predominant way to evaluate PA .
Most studies showed that PA promotes a protective effect against a higher BF gain .
CONCLUSION It was concluded that PA has a protective effect against BF with differences between the genders and according to the BF marker or measurement assessed ; higher intensity PA leads to a greater effect against BF gain in both genders ; and the maintenance or increase of PA level on BF observed through analysis of change in PA level yielded more consistent findings in the relation between PA and BF
BACKGROUND Physical activity ( PA ) practice has been inversely associated to body  fat ( BF ) and recommended as a way to reduce and prevent obesity .
The objective of this study was to conduct a systematic review on the association of  PA and BF in adolescence .
Relation between the changes in physical activity and body-mass index during adolescence: a multicentre longitudinal study
BACKGROUND The role of physical activity in preventing obesity during adolescence remains unknown . We examined changes in activity in relation to changes in body-mass index ( BMI ) and adiposity in a cohort of 1152 black and 1135 white girls from the USA , who were followed up prospect ively from ages 9 or 10 to 18 or 19 years . METHODS BMI and sum of skinfold thickness were assessed annually , whereas habitual activity was assessed at years 1 ( baseline ) , 3 , 5 , and 7 - 10 . Each girls ' overall activity status was categorised as active , moderately active , or inactive . Longitudinal regression models examined associations between changes in activity and in overall activity status with changes in BMI and in sum of skinfold thickness . FINDINGS Each decline in activity of 10 metabolic equivalent [MET]-times per week was associated with an increase in BMI of 0.14 kg/m2 ( SE 0.03 ) and in sum of skinfold thickness of 0.62 mm ( 0.17 ) for black girls , and of 0.09 kg/m2 ( 0.02 ) and 0.63 mm ( 0.13 ) for white girls . At ages 18 or 19 years , BMI differences between active and inactive girls were 2.98 kg/m2 ( p<0.0001 ) for black girls and 2.10 kg/m2 ( p<0.0001 ) for white girls . Similar results were apparent for sum of skinfold thickness . For moderately active girls , changes in BMI and sum of skinfold thickness were about midway between those for active and inactive girls . INTERPRETATION Changes in activity levels of US girls during adolescence significantly affected changes in BMI and adiposity . Thus , preventing the steep decline in activity during adolescence is an important method to reduce obesity
Question naires were the more predominant way to evaluate PA .
Most studies showed that PA promotes a protective effect against a higher BF gain .
CONCLUSION It was concluded that PA has a protective effect against BF with differences between the genders and according to the BF marker or measurement assessed ; higher intensity PA leads to a greater effect against BF gain in both genders ; and the maintenance or increase of PA level on BF observed through analysis of change in PA level yielded more consistent findings in the relation between PA and BF
BACKGROUND Physical activity ( PA ) practice has been inversely associated to body  fat ( BF ) and recommended as a way to reduce and prevent obesity .
The objective of this study was to conduct a systematic review on the association of  PA and BF in adolescence .