Overall , total PA was favourably associated with physical , psychological/social , and cognitive health indicators .
Relationships were more consistent and robust for higher ( e.g. , MVPA ) versus lower ( e.g. , LPA ) intensity PA .
All patterns of activity ( sporadic , bouts , continuous ) provided benefit .
LPA was favourably associated with cardiometabolic biomarkers ; data were scarce for other outcomes .
These findings continue to support the importance of at least 60 min/day of MVPA for disease prevention and health promotion in children and youth , but also highlight the potential benefits of LPA and total PA .
Moderate-to-vigorous physical activity ( MVPA ) is essential for disease prevention and health promotion .
Emerging evidence suggests other intensities of physical activity ( PA ) , including light-intensity activity ( LPA ) , may also be important , but there has been no rigorous evaluation of the evidence .
The purpose of this systematic review was to examine the relationships between objective ly measured PA ( total and all intensities ) and health indicators in school-aged children and youth .
Online data bases were search ed for peer- review ed studies that met the a priori inclusion criteria : population ( apparently healthy , aged 5 - 17 years ) , intervention/exposure/comparator ( volumes , duration s , frequencies , intensities , and patterns of objective ly measured PA ) , and outcome ( body composition , cardiometabolic biomarkers , physical fitness , behavioural conduct/pro-social behaviour , cognition/academic achievement , quality of life/well-being , harms , bone health , motor skill development , psychological distress , self-esteem ) .
Relationships among fitness, body composition, and physical activity.
PURPOSE This study was design ed to examine the associations of physical activity and body composition with cardiorespiratory fitness in eighth grade girls . METHODS A r and om sample of 1440 eighth grade girls at 36 schools participated in this cross-sectional investigation , which represented an ethnically and geographically diverse group .  Cardiorespiratory fitness was assessed using a modified physical work capacity test on a cycle ergometer that predicted workload at a heart rate of 170 beats.min . Physical activity was assessed over 6 d in each girl using an accelerometer and body composition was estimated from body mass index and triceps skinfolds using a previously vali date d equation . Pearson correlations and multiple regression analyses were used to determine the relationships among fitness , physical activity , and body composition . RESULTS Significant linear relationships among cardiorespiratory fitness , body composition , and physical activity were found . The combination of fat and fat-free mass along with racial group and a race by fat-free-mass interaction accounted for 18 % ( R ) of the variation in physical fitness . Adding moderate-to-vigorous physical activity to the regression model increased the R to 22 % . Black girls had somewhat lower fitness levels ( P < 0.05 ) especially at higher levels of fat and fat-free mass than other racial/ethnic groups . CONCLUSIONS Physical activity , fat-free mass , and the interaction between fat-free mass and racial group are significantly associated with cardiorespiratory fitness in adolescent girls
Overall , total PA was favourably associated with physical , psychological/social , and cognitive health indicators .
Relationships were more consistent and robust for higher ( e.g. , MVPA ) versus lower ( e.g. , LPA ) intensity PA .
All patterns of activity ( sporadic , bouts , continuous ) provided benefit .
LPA was favourably associated with cardiometabolic biomarkers ; data were scarce for other outcomes .
These findings continue to support the importance of at least 60 min/day of MVPA for disease prevention and health promotion in children and youth , but also highlight the potential benefits of LPA and total PA .
Moderate-to-vigorous physical activity ( MVPA ) is essential for disease prevention and health promotion .
Emerging evidence suggests other intensities of physical activity ( PA ) , including light-intensity activity ( LPA ) , may also be important , but there has been no rigorous evaluation of the evidence .
The purpose of this systematic review was to examine the relationships between objective ly measured PA ( total and all intensities ) and health indicators in school-aged children and youth .
Online data bases were search ed for peer- review ed studies that met the a priori inclusion criteria : population ( apparently healthy , aged 5 - 17 years ) , intervention/exposure/comparator ( volumes , duration s , frequencies , intensities , and patterns of objective ly measured PA ) , and outcome ( body composition , cardiometabolic biomarkers , physical fitness , behavioural conduct/pro-social behaviour , cognition/academic achievement , quality of life/well-being , harms , bone health , motor skill development , psychological distress , self-esteem ) .