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 .
Bidirectional cross-sectional and prospective associations between physical activity and body composition in adolescence: Birth cohort study
Abstract The aim of this study was to investigate the cross-sectional and prospect i ve associations between physical activity and  body composition in adolescence . This is a prospect i ve study , including 4,103 adolescents belonging to the Pelotas ( Brazil ) 1993 birth cohort , who were followed up at the mean ages of 11.3 and 14.7 years . Sub sample analyses included 511 individuals with accelerometry and deuterium dilution data at 13.3 years .  Sum of skinfolds at age 11.3 years was highly correlated with skinfolds at age 14.7 years ( rho = 0.74 , P < 0.001 ) . More than 85 % of participants remained in the same quintile or changed by not more than one quintile during the 3.4 year period .  Tracking of physical activity  was considerably lower , although still significant ; the correlation was 0.24 ( P < 0.001 ) and 61.4 % of the adolescents moved one or less quintiles . In fully-adjusted models , no significant cross-sectional or longitudinal associations were found between physical activity and body composition , neither in boys nor in girls . These null results were confirmed in the 511 individuals with accelerometry and deuterium data . We provide evidence of  tracking of physical activity and particularly body composition during adolescence . Our results do not support the hypothesis that physical activity and fatness are strongly related in adolescents
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 .