human
***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: Background Identifying ways to promote physical activity and decrease sedentary time during childhood is a key public health issue . Research on the putative influences on preschool children ’s  physical activity ( PA ) and  sedentary behavior  ( SB ) is limited and has yielded inconsistent results . Our aim was to identify correlates of PA and SB in preschool children . Methods Cross-sectional data were drawn from the Swiss Preschoolers ’ Health Study ( SPLASHY ) , a Swiss population -based cohort study . Of 476 two to six year old children , 394 ( 54 % boys ) had valid PA data assessed by accelerometry .  Information on exposure data was directly measured or extracted from parental question naires . Multilevel linear regression modeling was used to separately assess associations between 35 potential correlates and  total PA ( TPA ) , moderate-to-vigorous PA ( MVPA ) and SB . Results In total , 12 correlates from different domains were identified . TPA and MVPA were greater in boys than girls , increased with age and were positively associated with gross motor skills . Children from single parent families had a higher level of TPA and spent less time sedentary than those living with two parents . Time spent outdoors was positively associated with TPA and negatively with SB . The child ’s activity temperament was related all three outcomes , whereas parental sports club membership , living area per person and neighborhood safety were associated with SB only . Fixed and r and om factors in the final models accounted for 28 % , 32 % and 22 % of the total variance in TPA , MVPA and SB , respectively . Variance decomposition revealed that age , sex and activity temperament were the most influential correlates of both , TPA and MVPA , whereas the child ’s activity temperament , time outdoors and neighborhood safety were identified as the most important correlates of SB . Conclusions A multidimensional set of correlates of young children ’s  activity behavior has been identified . Personal factors had the greatest influence on PA , whereas environmental-level factors had the greatest influence on SB . Moreover , we identified a number of previously unreported , potentially modifiable correlates of young children ’s PA and SB . These factors could serve to define target groups or become valuable targets for change in future interventions .Trial registration Current Controlled Trials IS RCT N41045021 ( date of registration : 21.03.14 ) Background : Recent studies have cl aim ed a positive effect of physical activity and body composition on vagal tone . In pediatric population s , there is a pronounced decrease in heart rate with age . While this decrease is often interpreted as an age-related increase in vagal tone , there is some evidence that it may be related to a decrease in intrinsic heart rate . This factor has not been taken into account in most previous studies . The aim of the present study was to assess the association between physical activity and /or body composition and heart rate variability ( HRV ) independently of the decline in heart rate in young children . Methods : Anthropometric measurements were taken in 309 children aged 2–6 years .  Ambulatory electrocardiograms  were collected over 14–18 h comprising a full night and accelerometry over 7 days . HRV was determined of three different night segments : ( 1 ) over 5 min during deep sleep identified automatically based on HRV characteristics ; ( 2 ) during a 20 min segment starting 15 min after sleep onset ; ( 3 ) over a 4-h segment between midnight and 4 a.m. Linear models were computed for HRV parameters with anthropometric and physical activity variables adjusted for heart rate and other confounding variables ( e.g. , age for physical activity models ) . Results : We found a decline in heart rate with increasing physical activity and decreasing skinfold thickness . HRV parameters decreased with increasing age , height , and weight in HR-adjusted regression models . These relationships were only found in segments of deep sleep detected automatically based on HRV or manually 15 min after sleep onset , but not in the 4-h segment with r and om sleep phases . Conclusions : Contrary to most previous studies , we found no increase of st and ard HRV parameters with age , however , when adjusted for heart rate , there was a significant decrease of HRV parameters with increasing age . Without knowing intrinsic heart rate correct interpretation of HRV in growing children is impossible Objective : This study assesses differences in adiposity , aerobic fitness , and lifestyle characteristics in preschoolers according to their weight status and sports club ( SC ) participation . Method : As part of the Ballabeina study , 600 r and omly selected preschoolers ( mean age 5.1 ± 0.6 years ; 50.2 % girls ) were analyzed . Body composition was measured by bioelectrical impedance , aerobic fitness by the 20-meter shuttle run test , and physical activity by accelerometers . Eating habits , media use , and SC participation were assessed by question naires . Results : Overweight children ( Swiss national percentiles ) and children not participating in SC had both lower aerobic fitness and higher % body fat compared to their respective counterparts ( all p ≤ 0.028 ) . In addition , children not participating in SC were less physically active , had more media use , and ate less healthy compared to children participating in SC ( all p ≤ 0.023 ) . Controlling for parental sociocultural determinants attenuated differences in % body fat , in physical activity , and in eating habits . Conclusion : Aerobic fitness differs both according to weight status and SC participation in preschoolers . Furthermore , in view of the many differences in lifestyle behaviors , SC participation at this age could represent a more discriminatory indicator of healthy lifestyle characteristics than weight status PURPOSE To determine if weight status modifies the relationship between motor skill ( MS ) performance and  physical activity ( PA )  in preschoolers . METHODS Preschoolers ( N = 227 , age 3 - 5 y ) were recruited from 22 preschools . Preschoolers ' MS ( locomotor , object control , and total MS ) were assessed with the Children 's Activity and Movement in Preschool Study MS protocol . PA was measured by accelerometry . Mixed linear models were used to examine the relationship of MS performance and body mass index ( BMI ) z score to PA . Models were adjusted for age , race , sex , and parent education , with preschool as a r and om effect . RESULTS There was a significant correlation between MS performance and PA ( r = .14-.17 , P < .05 ) . A significant interaction was observed between BMI z score and object control , and between BMI z score and total MS score on PA ( P = .03 ) . Preschoolers with higher BMI z scores and high object control scores engaged in significantly ( P = .03 ) more PA than preschoolers with lower BMI z scores and high object control scores ( PA = 15.04 min/h and 13.54 min/h , respectively ) . Similarly , preschoolers with higher BMI z scores and high total MS scores spent significantly ( P = .01 ) more time in  PA  compared with those with lower BMI z scores and high total MS scores ( PA = 15.65 min/h and 13.91 min/h , respectively ) . CONCLUSION Preschool children 's MS performance is positively correlated with PA , and BMI z score modified the relationship between MS performance and PA OBJECTIVE To examine , using an Ecological Systems Theoretical framework , relationships between weight status and child , parent and community characteristics and risk factors among preschool children . METHODS Cross-sectional data was collected from 140 children and their parents from 11 r and omly selected preschools . Outcome variables included : motor development ; perceived competence ; objective ly measured physical activity ; time spent in active and quiet play ; location and number of televisions ; parental rules around physical activity and time spent watching television ; availability of sport and physical activity programs ; and parks and open spaces and access to footpaths .  RESULTS Overweight children spent more time in quiet play and watching television  and less time in active play and physical activity . Perceived competence and motor development were similar for both overweight and non-overweight children . Associations between weight status and several parent and community characteristics were not evident , except for access to footpaths . Overweight children had greater access to footpaths  compared with non-overweight children ( p=0.046 ) . CONCLUSION The results reported here showed little difference between overweight and non-overweight children in relation to a variety of child , parent and community variables . However , for some characteristics , differences in older children have been reported . Longitudinal studies are required to confirm when these characteristics begin to differ , what effects these differences have on behaviour and weight-status , and therefore when targeted treatment should be provided during a child 's development OBJECTIVE Preventing weight gain in adults and excessive weight gain in children is a high priority . We evaluated the ability of a family-based program aim ed at increasing steps and cereal consumption ( for breakfast and snacks ) to reduce weight gain in children and adults . RESEARCH METHODS AND PROCEDURES Families ( n = 105 ) with at least one 8- to 12-year-old child who was at-risk-for-overweight or overweight ( design ated as the target child ) were recruited for the study . Eighty-two families were r and omly assigned to receive the family-based intervention and 23 families to the control condition .  The 13-week intervention consisted of specific increases in daily steps ( an additional 2000 steps/d ) and consumption of 2 servings/d of ready-to-eat cereal . RESULTS The intervention was successful in increasing walking ( steps ) and cereal consumption . The intervention had positive , significant effects on percentage BMI -for-age and percentage body fat for target children and weight , BMI , and percentage body fat for parents . On further analysis , the positive effects of the intervention were seen largely in target girls and moms , rather than in target boys and dads . DISCUSSION This family-based weight gain prevention program based on small changes holds promise for reducing excessive weight gain in families and especially in growing overweight children OBJECTIVE The impact of physical activity patterns and sleep duration on growth and body composition of preschool-aged children remains unresolved . Aims were ( 1 ) to delineate cross-sectional associations among physical activity components , sleep , total energy expenditure ( TEE ) , and body size and composition ; and ( 2 ) to determine whether physical activity components , sleep , and TEE predict 1-year changes in body size and composition in healthy preschool-aged children . METHODS Anthropometry , body composition , accelerometry , and TEE by doubly labeled water were measured at baseline ; anthropometry and body composition were repeated 1 year later ( n = 111 ) . RESULTS Cross-sectionally , positive associations between sedentary activity and weight and fat-free mass ( FFM ) ( P = 0.009 - 0.047 ) , and a negative association between moderate-vigorous physical activity ( MVPA ) and percent fat mass ( FM ) ( P = 0.015 ) were observed . TEE and activity energy expenditure ( AEE ) were positively associated with weight , body mass index ( BMI ) , FFM , and FM ( P = 0.0001 - 0.046 ) . Prospect ively , TEE , AEE , physical activity level , and MVPA , but not sedentary activity , were positively associated with changes in BMI ( P = 0.0001 - 0.051 ) and FFM ( P = 0.0001 - 0.037 ) , but not percent FM . Sleep duration inversely predicted changes in FM ( P = 0.005 ) and percent FM ( P = 0.006 ) . CONCLUSIONS Prospect ively , MVPA , TEE , AEE , and physical activity level promote normal growth and accretion of FFM , whereas sleep duration inversely predicts changes in adiposity in preschool-aged 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 
    Output:
    
agent
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
***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: Background Identifying ways to promote physical activity and decrease sedentary time during childhood is a key public health issue . Research on the putative influences on preschool children ’s  physical activity ( PA ) and  sedentary behavior  ( SB ) is limited and has yielded inconsistent results . Our aim was to identify correlates of PA and SB in preschool children . Methods Cross-sectional data were drawn from the Swiss Preschoolers ’ Health Study ( SPLASHY ) , a Swiss population -based cohort study . Of 476 two to six year old children , 394 ( 54 % boys ) had valid PA data assessed by accelerometry .  Information on exposure data was directly measured or extracted from parental question naires . Multilevel linear regression modeling was used to separately assess associations between 35 potential correlates and  total PA ( TPA ) , moderate-to-vigorous PA ( MVPA ) and SB . Results In total , 12 correlates from different domains were identified . TPA and MVPA were greater in boys than girls , increased with age and were positively associated with gross motor skills . Children from single parent families had a higher level of TPA and spent less time sedentary than those living with two parents . Time spent outdoors was positively associated with TPA and negatively with SB . The child ’s activity temperament was related all three outcomes , whereas parental sports club membership , living area per person and neighborhood safety were associated with SB only . Fixed and r and om factors in the final models accounted for 28 % , 32 % and 22 % of the total variance in TPA , MVPA and SB , respectively . Variance decomposition revealed that age , sex and activity temperament were the most influential correlates of both , TPA and MVPA , whereas the child ’s activity temperament , time outdoors and neighborhood safety were identified as the most important correlates of SB . Conclusions A multidimensional set of correlates of young children ’s  activity behavior has been identified . Personal factors had the greatest influence on PA , whereas environmental-level factors had the greatest influence on SB . Moreover , we identified a number of previously unreported , potentially modifiable correlates of young children ’s PA and SB . These factors could serve to define target groups or become valuable targets for change in future interventions .Trial registration Current Controlled Trials IS RCT N41045021 ( date of registration : 21.03.14 ) Background : Recent studies have cl aim ed a positive effect of physical activity and body composition on vagal tone . In pediatric population s , there is a pronounced decrease in heart rate with age . While this decrease is often interpreted as an age-related increase in vagal tone , there is some evidence that it may be related to a decrease in intrinsic heart rate . This factor has not been taken into account in most previous studies . The aim of the present study was to assess the association between physical activity and /or body composition and heart rate variability ( HRV ) independently of the decline in heart rate in young children . Methods : Anthropometric measurements were taken in 309 children aged 2–6 years .  Ambulatory electrocardiograms  were collected over 14–18 h comprising a full night and accelerometry over 7 days . HRV was determined of three different night segments : ( 1 ) over 5 min during deep sleep identified automatically based on HRV characteristics ; ( 2 ) during a 20 min segment starting 15 min after sleep onset ; ( 3 ) over a 4-h segment between midnight and 4 a.m. Linear models were computed for HRV parameters with anthropometric and physical activity variables adjusted for heart rate and other confounding variables ( e.g. , age for physical activity models ) . Results : We found a decline in heart rate with increasing physical activity and decreasing skinfold thickness . HRV parameters decreased with increasing age , height , and weight in HR-adjusted regression models . These relationships were only found in segments of deep sleep detected automatically based on HRV or manually 15 min after sleep onset , but not in the 4-h segment with r and om sleep phases . Conclusions : Contrary to most previous studies , we found no increase of st and ard HRV parameters with age , however , when adjusted for heart rate , there was a significant decrease of HRV parameters with increasing age . Without knowing intrinsic heart rate correct interpretation of HRV in growing children is impossible Objective : This study assesses differences in adiposity , aerobic fitness , and lifestyle characteristics in preschoolers according to their weight status and sports club ( SC ) participation . Method : As part of the Ballabeina study , 600 r and omly selected preschoolers ( mean age 5.1 ± 0.6 years ; 50.2 % girls ) were analyzed . Body composition was measured by bioelectrical impedance , aerobic fitness by the 20-meter shuttle run test , and physical activity by accelerometers . Eating habits , media use , and SC participation were assessed by question naires . Results : Overweight children ( Swiss national percentiles ) and children not participating in SC had both lower aerobic fitness and higher % body fat compared to their respective counterparts ( all p ≤ 0.028 ) . In addition , children not participating in SC were less physically active , had more media use , and ate less healthy compared to children participating in SC ( all p ≤ 0.023 ) . Controlling for parental sociocultural determinants attenuated differences in % body fat , in physical activity , and in eating habits . Conclusion : Aerobic fitness differs both according to weight status and SC participation in preschoolers . Furthermore , in view of the many differences in lifestyle behaviors , SC participation at this age could represent a more discriminatory indicator of healthy lifestyle characteristics than weight status PURPOSE To determine if weight status modifies the relationship between motor skill ( MS ) performance and  physical activity ( PA )  in preschoolers . METHODS Preschoolers ( N = 227 , age 3 - 5 y ) were recruited from 22 preschools . Preschoolers ' MS ( locomotor , object control , and total MS ) were assessed with the Children 's Activity and Movement in Preschool Study MS protocol . PA was measured by accelerometry . Mixed linear models were used to examine the relationship of MS performance and body mass index ( BMI ) z score to PA . Models were adjusted for age , race , sex , and parent education , with preschool as a r and om effect . RESULTS There was a significant correlation between MS performance and PA ( r = .14-.17 , P < .05 ) . A significant interaction was observed between BMI z score and object control , and between BMI z score and total MS score on PA ( P = .03 ) . Preschoolers with higher BMI z scores and high object control scores engaged in significantly ( P = .03 ) more PA than preschoolers with lower BMI z scores and high object control scores ( PA = 15.04 min/h and 13.54 min/h , respectively ) . Similarly , preschoolers with higher BMI z scores and high total MS scores spent significantly ( P = .01 ) more time in  PA  compared with those with lower BMI z scores and high total MS scores ( PA = 15.65 min/h and 13.91 min/h , respectively ) . CONCLUSION Preschool children 's MS performance is positively correlated with PA , and BMI z score modified the relationship between MS performance and PA OBJECTIVE To examine , using an Ecological Systems Theoretical framework , relationships between weight status and child , parent and community characteristics and risk factors among preschool children . METHODS Cross-sectional data was collected from 140 children and their parents from 11 r and omly selected preschools . Outcome variables included : motor development ; perceived competence ; objective ly measured physical activity ; time spent in active and quiet play ; location and number of televisions ; parental rules around physical activity and time spent watching television ; availability of sport and physical activity programs ; and parks and open spaces and access to footpaths .  RESULTS Overweight children spent more time in quiet play and watching television  and less time in active play and physical activity . Perceived competence and motor development were similar for both overweight and non-overweight children . Associations between weight status and several parent and community characteristics were not evident , except for access to footpaths . Overweight children had greater access to footpaths  compared with non-overweight children ( p=0.046 ) . CONCLUSION The results reported here showed little difference between overweight and non-overweight children in relation to a variety of child , parent and community variables . However , for some characteristics , differences in older children have been reported . Longitudinal studies are required to confirm when these characteristics begin to differ , what effects these differences have on behaviour and weight-status , and therefore when targeted treatment should be provided during a child 's development OBJECTIVE Preventing weight gain in adults and excessive weight gain in children is a high priority . We evaluated the ability of a family-based program aim ed at increasing steps and cereal consumption ( for breakfast and snacks ) to reduce weight gain in children and adults . RESEARCH METHODS AND PROCEDURES Families ( n = 105 ) with at least one 8- to 12-year-old child who was at-risk-for-overweight or overweight ( design ated as the target child ) were recruited for the study . Eighty-two families were r and omly assigned to receive the family-based intervention and 23 families to the control condition .  The 13-week intervention consisted of specific increases in daily steps ( an additional 2000 steps/d ) and consumption of 2 servings/d of ready-to-eat cereal . RESULTS The intervention was successful in increasing walking ( steps ) and cereal consumption . The intervention had positive , significant effects on percentage BMI -for-age and percentage body fat for target children and weight , BMI , and percentage body fat for parents . On further analysis , the positive effects of the intervention were seen largely in target girls and moms , rather than in target boys and dads . DISCUSSION This family-based weight gain prevention program based on small changes holds promise for reducing excessive weight gain in families and especially in growing overweight children OBJECTIVE The impact of physical activity patterns and sleep duration on growth and body composition of preschool-aged children remains unresolved . Aims were ( 1 ) to delineate cross-sectional associations among physical activity components , sleep , total energy expenditure ( TEE ) , and body size and composition ; and ( 2 ) to determine whether physical activity components , sleep , and TEE predict 1-year changes in body size and composition in healthy preschool-aged children . METHODS Anthropometry , body composition , accelerometry , and TEE by doubly labeled water were measured at baseline ; anthropometry and body composition were repeated 1 year later ( n = 111 ) . RESULTS Cross-sectionally , positive associations between sedentary activity and weight and fat-free mass ( FFM ) ( P = 0.009 - 0.047 ) , and a negative association between moderate-vigorous physical activity ( MVPA ) and percent fat mass ( FM ) ( P = 0.015 ) were observed . TEE and activity energy expenditure ( AEE ) were positively associated with weight , body mass index ( BMI ) , FFM , and FM ( P = 0.0001 - 0.046 ) . Prospect ively , TEE , AEE , physical activity level , and MVPA , but not sedentary activity , were positively associated with changes in BMI ( P = 0.0001 - 0.051 ) and FFM ( P = 0.0001 - 0.037 ) , but not percent FM . Sleep duration inversely predicted changes in FM ( P = 0.005 ) and percent FM ( P = 0.006 ) . CONCLUSIONS Prospect ively , MVPA , TEE , AEE , and physical activity level promote normal growth and accretion of FFM , whereas sleep duration inversely predicts changes in adiposity in preschool-aged 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 
    Output:
    