Results Physical activity was associated with numerous health benefits .
The dose-response relations observed in observational studies indicate that the more physical activity , the greater the health benefit .
Results from experimental studies indicate that even modest amounts of physical activity can have health benefits in high-risk youngsters ( e.g. , obese ) .
Vigorous intensity activities may provide even greater benefit .
Aerobic-based activities had the greatest health benefit , other than for bone health , in which case high-impact weight bearing activities were required .
Some of the health benefits can be achieved through an average of 30 minutes per day . [
Level 2 , Grade A ] .
Background The purpose was to : 1 ) perform a systematic review of studies examining the relation between physical activity , fitness , and health in school-aged children and youth , and 2 ) make recommendations based on the findings .
Relationship of physical fitness to prevalence and incidence of overweight among schoolchildren.
OBJECTIVES We examined the relationship between comprehensive fitness tests and overweight using a school surveillance system in a racially diverse city in the United States . RESEARCH METHODS AND PROCEDURES Trained physical education teachers  measured weight , height , and fitness annually from 2001 to 2003 . We compiled data for a cross-sectional analysis ( 11,845 measurements on 6297 students , 5 to 14 years of age ) and a 1-year prospect i ve analysis ( 4215 measurements on 2927 students not overweight at baseline , 5 to 13 years of age ) . Overweight was defined as a BMI > or = 95th percentile ( Centers for Disease Control and Prevention 2000 growth charts ) , and underfit was defined as failing at least one of five fitness tests : endurance run , abdominal strength , flexibility , upper body strength , and agility ( Amateur Athletic Union and Fitnessgram ) . Associations between fitness and overweight were examined using multivariate logistic regression models , adjusting for sociodemographic status and repeated measurements over time . RESULTS The mean number of fitness tests passed was lower among students with a BMI above the 80th percentile . Overweight incidence over 1 year was 7 % and 2 % for underfit and fit girls , respectively ( odds ratio , 3.3 ; 95 % confidence interval , 2.0 to 5.6 ) . Not passing either the endurance run or upper body strength test was associated with overweight incidence in both boys and girls . After adjusting for baseline BMI , the endurance run remained a significant predictor of incident overweight among girls ( odds ratio , 2.0 ; 95 % confidence interval , 1.1 to 3.5 ) . DISCUSSION Findings support a cross-sectional inverse relationship between physical fitness and  overweight among school-aged children . The direction of causation between fitness and overweight is not clearly established and merits further study
Results Physical activity was associated with numerous health benefits .
The dose-response relations observed in observational studies indicate that the more physical activity , the greater the health benefit .
Results from experimental studies indicate that even modest amounts of physical activity can have health benefits in high-risk youngsters ( e.g. , obese ) .
Vigorous intensity activities may provide even greater benefit .
Aerobic-based activities had the greatest health benefit , other than for bone health , in which case high-impact weight bearing activities were required .
Some of the health benefits can be achieved through an average of 30 minutes per day . [
Level 2 , Grade A ] .
Background The purpose was to : 1 ) perform a systematic review of studies examining the relation between physical activity , fitness , and health in school-aged children and youth , and 2 ) make recommendations based on the findings .