However , total PA , sedentary behaviour , and different PA intensities were not associated with body mass index ( BMI ) or waist circumference .
Adiposity levels were lower among preschool children engaged in more ( moderate-to- ) vigorous PA compared with their peers , but no associations  between  PA and BMI or waist circumference were found
Evidence on the association between  physical activity ( PA ) and adiposity in young children is inconclusive .
A systematic review and meta-analyses were conducted to examine associations between accelerometer-derived PA and varying adiposity outcomes  in preschool children .
Relationship between physical activity and the development of body mass index in children.
PURPOSE Studies estimating the contribution of physical activity ( PA ) to the development of body mass index ( BMI ) in critical periods of childhood are warranted . Therefore , we have prospect ively investigated this relationship in boys and girls of the KOALA Birth Cohort study , the Netherl and s , in the period around adiposity rebound ( i.e. , 4 - 9 yr old ) . METHODS PA was  assessed  in 470 children ( 231 boys , 239 girls ) using accelerometers at the ages of 5 and 7 yr , and height and weight were measured at 5 , 7 , and 9 yr .  BMI z-scores were calculated to st and ardize for age and sex . Leaner and heavier children were classified according to the 25th and 75th percentile of our study sample . To examine longitudinal relationships between PA and BMI z-scores , generalized estimating equation analyses were performed and stratified for sex and baseline weight status ( leaner , normal weight , and heavier children ) . RESULTS In heavier children , an increment of 6.5 min of moderate to vigorous PA ( MVPA ) was related to a subsequent decrease of 0.03 BMI z-scores both in boys ( 95 % confidence interval = -0.07 to -0.001 ) and girls ( 95 % confidence interval = -0.05 to -0.002 ) . Light PA was also associated with a decrease of BMI in heavier boys but not girls . In normal weight children , MVPA was associated with decrease of BMI in boys but not girls . CONCLUSION Increments of MVPA were associated with decreases in BMI z-score in heavier children , both boys and girls . Promoting MVPA should remain a major prevention vehicle for improving body composition in 4- to 9-yr-old children
However , total PA , sedentary behaviour , and different PA intensities were not associated with body mass index ( BMI ) or waist circumference .
Adiposity levels were lower among preschool children engaged in more ( moderate-to- ) vigorous PA compared with their peers , but no associations  between  PA and BMI or waist circumference were found
Evidence on the association between  physical activity ( PA ) and adiposity in young children is inconclusive .
A systematic review and meta-analyses were conducted to examine associations between accelerometer-derived PA and varying adiposity outcomes  in preschool children .