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 .
Physical activity energy expenditure predicts changes in body composition in middle-aged healthy whites: effect modification by age.
BACKGROUND It is unclear whether physical activity energy expenditure ( PAEE ) predicts changes in body composition . OBJECTIVE The objective was to describe the independent associations between PAEE and changes in body composition in a population -based cohort . DESIGN This was a prospect i ve population -based study conducted in 739 ( 311 men and 428 women ) healthy middle-aged ( median age : 53.8 y ) whites . The median follow-up was 5.6 y. PAEE ( MJ/d ) was assessed by heart rate monitoring , individually calibrated by using the FLEX heart rate method .  Fat mass ( FM ) and fat-free mass ( FFM ) were assessed by bioimpedance . RESULTS Body weight ( BW ) at follow-up was significantly related to baseline PAEE ( P < 0.05 ) after adjustment for sex , baseline age , FM , FFM , and follow-up time . A significant interaction between PAEE and age ( P = 0.023 ) was observed . After the subjects were stratified ( above and below the median for age ) , BW increased by a mean ( + /-SD ) of 1.7 + /- 5.9 kg ( P < 0.0001 ) in the younger cohort . In this group , follow-up FM was significantly associated with baseline PAEE ( P = 0.036 ) after adjustment for confounders . In the older cohort , BW did not change between baseline and follow-up . In this group , in contrast with the younger population , follow-up BW , FM , and FFM were all significantly and positively associated with baseline PAEE ( P < 0.01 for all ) . CONCLUSIONS Baseline PAEE predicts a change in FM  in younger adults , who as a group gained weight in this study . In contrast , baseline PAEE  in older adults -- who were on average weight stable -- is associated with a gain in BW , which was explained by an increase in FM and FFM
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 .