Objectively measured physical activity and sedentary time: cross-sectional and prospective associations with adiposity in the Millennium Cohort Study Effects of Child Care Intervention on Physical Activity and Body Composition. Gender differences in response to a physical activity intervention in overweight and obese children. A comprehensive physical activity promotion programme at elementary school: the effects on physical activity, physical fitness and psychosocial correlates of physical activity. Comparative Effectiveness of a 12-Week Physical Activity Intervention for Overweight and Obese Youth: Exergaming with "Dance Dance Revolution". Fatness leads to inactivity, but inactivity does not lead to fatness: a longitudinal study in children (EarlyBird 45) Correlates of preschool children’s objectively measured physical activity and sedentary behavior: a cross-sectional analysis of the SPLASHY study Cross-sectional and prospective associations between moderate to vigorous physical activity and sedentary time with adiposity in children The effect of a classroom activity break on physical activity levels and adiposity in primary school children. Feasibility and Effectiveness of a Wearable Technology-Based Physical Activity Intervention in Preschoolers: A Pilot Study Assessing Causality in the Association between Child Adiposity and Physical Activity Levels: A Mendelian Randomization Analysis Ability of physical activity measurements to assess health-related risks Physical activity and its correlates in children: a cross-sectional study (the GINIplus & LISAplus studies) Effects of modifying physical activity and sedentary behavior on psychosocial adjustment in overweight/obese children. Relationship between physical activity and the development of body mass index in children. Influence of extracurricular sport activities on body composition and physical fitness in boys: a 3-year longitudinal study Estimating absolute and relative physical activity intensity across age via accelerometry in adults.
Objective To examine whether physical activity ( PA ) and sedentary time ( ST ) in primary school-aged children are associated with adiposity at the start of secondary school , and whether these associations differ by sex or ethnic group . Design Nationally representative prospect i ve cohort study . Setting Children born across the UK , between 2000 and 2002 . Participants 6497 singleton children . Outcome measures Measures of adiposity ( body mass index ( BMI ) , fat mass index ( FMI ) and fat free mass index (FFMI))—obtained at 7 and 11 years . Explanatory measures  Total daily PA ( mean counts per minute ( cpm ) ) ; minutes of moderate-to-vigorous PA ( MVPA ) ; and ST .  All assessed at 7 years using accelerometers . Results In cross-sectional analyses , total PA was inversely associated with FMI ( 3.7 % ( 95 % CI 2.7 % to 4.7 % ) reduction per 150 cpm increase ) , as was MVPA ( 4.2 % ( CI 3.2 % to 5.2 % ) reduction per 20 min/day increase ) . Associations were stronger in black and South Asian ethnic groups . Total PA and MVPA were not associated with FFMI . ST was positively associated with FMI ( 1.3 % ( CI 0.2 % to 2.3 % ) increase per 50 min/day increase ) and inversely associated with FFMI ( 0.5 % ( CI 0.2 % to 0.7 % ) reduction per 50 min/day increase ) . Longitudinally , MVPA at age 7 years remained inversely associated with FMI at age 11 years ( 1.5 % ( CI 0.4 % to 2.6 % ) reduction per 20 min/day increase ) . No association was found between total PA and ST and any of the later adiposity measures . Conclusions 7-year-old children who are more physically active are less likely to be obese at that age and at age 11 years . These associations were particularly evident in children from black or South Asian ethnicity at age 7 years and in boys at age 11 years . Measurements of fat mass provide valuable insights into ethnic differences in associations between adiposity and activity INTRODUCTION This study evaluated whether intervening with child care providers would increase physical activity ( PA )  and reduce adiposity in preschoolers . METHODS This was a two-arm , parallel group , cluster RCT whereby six child care centers were r and omly assigned in equal numbers to intervention ( n=40 children ) or control ( n=43 children ) . Participants were aged 3 - 5 years and attended licensed child care centers . Child care providers received two 3-hour train-the-trainer workshops and a training manual at program initiation aim ed at increasing structured and unstructured PA through active play . Control child care centers implemented their st and ard curriculum .  PA and sedentary behavior were measured by accelerometry , and body composition was measured using bioelectrical impedance at baseline and 6 months . Data were collected in 2011 - 2012 and analyzed in April 2015 . RESULTS Linear mixed-effects modeling showed that at 6 months , children in the intervention group demonstrated greater increases in minutes per preschool day spent in overall PA ( 22.5 minutes , 95 % CI=8.9 , 36.1 , p=0.002 ) , and light-intensity PA ( 16.1 minutes , 95 % CI=5.2 , 26.7 , p=0.004 ) , but changes between groups in moderate to vigorous PA did not differ . The intervention group showed greater reductions in body fat percentage ( -1.9 % , 95 % CI=-3.5 , -0.3 , p=0.023 ) and fat mass ( -0.3 kg , 95 % CI=-0.7 , -0.1 , p=0.018 ) , but groups did not differ on fat-free mass , BMI , or z- BMI . CONCLUSIONS Provider-led intervention in child care centers increased preschoolers '  PA and reduced adiposity , therefore may represent a viable approach to promoting PA and related health benefits in preschool-aged children . TRIAL REGISTRATION This study is registered at www . clinical trials.gov NCT02293278 BACKGROUND This study evaluated the effects of gender on response to a behavioral intervention that rewarded increases in  physical activity ( PA ) with increases in access to TV viewing . METHODS We performed a secondary analysis of a clinical trial that r and omized 30 overweight or obese , 8- to 12-year-old children to an intervention ( 8 boys , 6 girls ) or control ( 7 boys , 9 girls ) group . Participants wore accelerometers every day for 8 weeks and attended biweekly meetings to download the activity monitors . For the intervention group , accumulating 400 counts of PA on accelerometers earned 1 hour of TV time , which was controlled by a Token TV electronic device . Controls wore activity monitors but had free access to TV . RESULTS Compared with girls , boys in the intervention group exhibited greater increases in overall daily PA counts ( 110 % versus 40 % , P < .05 ) and minutes per day of moderate-to-vigorous physical activity ( MVPA ; + 18.1 versus + 2.7 , P < .05 ) . Neither boys nor girls in the control group showed significant changes in overall PA or intensity of PA . CONCLUSION Wearing an accelerometer in combination with rewarding PA with TV might be a more effective intervention for increasing overall PA and time spent in MVPA in overweight and obese boys than it is for overweight or obese girls OBJECTIVE To evaluate the effects of a comprehensive physical activity ( PA ) promotion programme in elementary schools on children 's total PA levels , leisure-time PA , physical fitness and psychosocial correlates of PA . DESIGN A pre-test-post-test design over two school years . SETTING AND SUBJECTS Sixteen elementary schools ( 764 children , mean age : 11.2 + /- 0.7 years ) were r and omly assigned to the intervention condition ( n = 8) and the control condition ( n = 8) . The intervention included a health-related physical education programme , an extracurricular PA promotion programme and classroom-based PA education lessons . In the total sample , leisure-time PA , psychosocial correlates of PA and physical fitness were measured using a PA question naire and the Eurofit test battery . In a sub- sample , total PA levels were measured using an accelerometer . RESULTS According to accelerometer data , children 's moderate PA and moderate-to-vigorous PA ( MVPA ) levels decreased less in the intervention schools than in the control schools ( P < 0.01 ) . The average time spent on MVPA decreased by 9 min per day in the intervention schools compared with 33 min per day in the control schools . Children in the intervention schools reported significantly more moderate PA in leisure time than the controls ( P < 0.05 ) . No overall improvement of physical fitness and no effects on the psychosocial correlates of PA were found . CONCLUSIONS The comprehensive PA promotion programme was successful in preventing a decline in children 's  total activity levels . Furthermore , the intervention increased children 's PA engagement in leisure time . Therefore , implementation needs to be encouraged OBJECTIVE Experts recommend that children engage in 60 minutes of daily moderate to vigorous PA ( PA ) , but few meet these goals . Exergames like " Dance Dance Revolution " ( DDR ) ( Konami of America , Redwood City , CA ) have the potential to provide PA . We sought to determine if DDR would boost PA among overweight or obese children . SUBJECTS AND METHODS Children over the 85th percentile for body mass index ( BMI ) and between 9 and 17 years old were r and omly assigned to receive DDR+pedometers ( treatment group ) or pedometers only ( comparison group ) .  PA levels were tracked for 12 weeks by self-report , pedometer , and accelerometer data . RESULTS Sixty-five families completed the study . The average  BMI percentile of the participant was over 96 percent . Despite r and omization , participants in the treatment ( DDR )  group were more often male , older , and heavier than participants in the comparison group . Self-reported frequency of moderate to vigorous PA increased significantly from baseline to 12 weeks for the treatment group and declined for the comparison group . Accelerometer results indicated a significant decline in moderate activity over time for the comparison group . However , there were no significant between-group differences based on the accelerometer or pedometer data . CONCLUSION Based on self-report measures , DDR may have increased PA levels in obese and overweight children . However , we are led to question the validity of these results because analyses based on objective measures do not confirm them . Accelerometer results indicate that although DDR did not boost PA , it may have helped to slow the decline in moderate to vigorous PA over time Objective To establish in children whether inactivity is the cause of fatness or fatness the cause of inactivity . Design A non-intervention prospect i ve cohort study examining children annually from 7 to 10 years . Baseline versus change to follow-up associations were used to examine the direction of causality . Setting Plymouth , Engl and . Participants 202 children ( 53 % boys , 25 % overweight/obese ) recruited from 40 Plymouth primary schools as part of the EarlyBird study . Main outcome measures  Physical activity ( PA ) was measured using Actigraph accelerometers . The children wore the accelerometers for 7 consecutive days at each annual time point . Two components of PA were analysed : the total volume of PA and the time spent at moderate and vigorous intensities . Body fat per cent ( BF% ) was measured annually by dual energy x ray absorptiometry . Results BF% was predictive of changes in PA  over the following 3 years , but PA levels were not predictive of subsequent changes in BF% over the same follow-up period . Accordingly , a 10 % higher BF% at age 7 years predicted a relative decrease in daily moderate and vigorous intensities of 4 min from age 7 to 10 years ( r=−0.17 , p=0.02 ) , yet more PA at 7 years did not predict a relative decrease in BF% between 7 and 10 years ( r=−0.01 , p=0.8 ) . Conclusions Physical inactivity appears to be the result of fatness rather than its cause . This reverse causality may explain why attempts to tackle childhood obesity by promoting PA have been largely unsuccessful 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 : Physical activity ( PA ) and sedentary time ( SED ) have both been suggested as potential risk factors for adiposity in children . However , there is paucity of data examining the temporal associations between these variables . Objective : This study aim ed to analyze the cross-sectional and prospect i ve associations between PA , SED and body composition in children . Methods : A total of 510 children ( age at baseline 10.1±0.8 , age at follow-up 11.8±0.9 ) from six Portuguese schools from the Oeiras Municipality participated in this study .  PA and SED were measured by accelerometry and trunk fat mass ( TFM ) and body fat mass ( BFM )  were measured by dual energy X-ray absorptiometry .  Fat mass index ( FMI ) was calculated as BFM divided by height squared . Several regression models adjusted for age , sex , maturity status , follow-up duration , baseline levels of the outcome variable and SED or moderate to vigorous PA ( MVPA ) were performed . Results : MVPA ( min per day ) was cross-sectionally inversely associated with adiposity indexes ( FMI , TFM and BFM ) . Adiposity indexes were inversely associated with time in MVPA . In prospect i ve analyses , MVPA was associated with a lower levels of FMI ( β=−0.37 , 95 % confidence interval ( CI ) : −0.49 to −0.26 , P<0.001 ) , TFM ( β=−0.20 , 95 % CI : −0.29 to −0.10 , P<0.001 ) and BFM ( β=−0.37 , 95 % CI : −0.49 to −0.26 , P<0.001 ) . When the model was adjusted for age , sex , maturity status and for baseline levels of the outcome variables MVPA remained a significant predictor of lower adiposity indexes ( FMI : β=−0.09 , 95 % CI : −0.16 to −0.01 , P<0.05 ; TFM : β=−0.08 , 95 % CI : −0.15 to −0.01 , P<0.05 ; BFM : β=−0.07 , 95 % CI : −0.15 to 0.00 , P<0.05 ) . Adiposity was not associated  with MVPA when modeled as the exposure in prospect i ve analyses . SED was not related with adiposity indexes , except for the relationship with FMI . Conclusions : In cross-sectional and prospect i ve analyses , MVPA is associated with lower adiposity independent of covariates and SED . Results suggest that promoting MVPA is important for preventing gain in adiposity in healthy children AIM Despite recognition that regular physical activity is essential for good health , many children do not accumulate sufficient daily physical activity . The aim of this study was to examine the effect of a classroom-based activity break on accelerometer-determined moderate-to-vigorous intensity physical activity ( MVPA ) and adiposity in primary school children . METHODS One hundred twenty children from seven primary schools in Northern Irel and participated in the study . In each school , one class of children was r and omly assigned to an intervention group and another class to a control group . Teachers of the intervention classes led a 5-min activity break three times per day for 12 weeks .  Accelerometer-determined MVPA , height , weight and four skinfolds  were measured at baseline and post-intervention . RESULTS Compared with the control group , the intervention group significantly increased weekday MVPA ( + 9.5 min ) from baseline to post-intervention . There were no significant changes in BMI ; however , an increase in sum-of-skinfolds of the intervention group was observed . CONCLUSIONS Classroom-based activity breaks led by the teacher are successful in increasing  children 's  physical activity levels . The programme shows a positive step in improving overall physical activity levels and contributing to the goal of 60 min daily MVPA The purpose of this pilot study was to evaluate the feasibility and the effectiveness of an intervention that employed a technology-based physical activity ( PA ) monitoring system and teacher-regulated strategies to promote PA  in preschoolers . A total of 93 preschoolers ( 53 % girls , 4.7 years ) from 5 child care centers were recruited for a one-week intervention and r and omly assigned into control ( 2 centers , n = 45 ) or intervention ( 3 centers , n = 48 ) group . Key intervention components included : ( 1 ) wearable device-based , real-time monitoring of children ’s PA by classroom teachers and ( 2 ) teacher-regulated strategies for providing more opportunities for PA . Sedentary behavior ( SED ) and PA were measured using accelerometers . Overall , children in the intervention group showed significantly lower level of SED ( 31.6 vs. 33.6 min/h ) and higher level of total PA ( 28.4 vs. 26.4 min/h ) than children in the control group , after adjusting for age , sex , race , parent education level , parent perception of their child ’s PA , BMI , and childcare centers . Teachers in the intervention group reported that the intervention was highly feasible to be implemented in their current classroom setting s. In conclusion , we observed high acceptability and initial effectiveness of the current intervention . Subsequent research at larger-scale is warranted to fully evaluate the effectiveness of the intervention strategies tested in this study Here , Timpson and colleagues performed a Mendelian R and omization analysis to determine whether childhood adiposity causally influences levels of  physical activity .  The results suggest that increased adiposity causes a reduction in physical activity  in children ; however , this study does not exclude lower physical activity also leading to increasing adiposity . Please see later in the article for the Editors ' The aim of this study is to evaluate if two different physical activity ( PA ) question naires have similar ability to rank individuals , and to examine associations with cardiovascular-metabolic risk factors , compared to an objective measure . In a r and om sample ( n=369 , age : 65±6 years ) from the population -based ‘ Malmö Diet and Cancer ’ ( MDC ) cohort , PA was measured by a leisure-time comprehensive question naire ( MDC-score ) , a simple leisure-time question naire and by accelerometer-monitoring ( CSA ) . Moderate correlations were observed between MDC-score and CSA in men and women ( r=0.35 and 0.24 , respectively ) . In men , both question naires and CSA were inversely associated with waist circumference , insulin resistance and metabolic syndrome . In women , the MDC-score was positively associated with high-density lipoprotein-cholesterol , and the simple question naire inversely associated with anthropometric indexes , but no association was seen between PA estimates and cardiovascular components . We conclude that both PA question naires distinguish health risks associated with anthropometric-metabolic risk factors , particularly in men Background Physical inactivity  among children is an increasing problem that adversely affects children ’s health . A better underst and ing of factors which affect  physical activity ( PA ) will help create effective interventions aim ed at raising the activity levels of children . This cross-sectional study examined the associations of PA with individual ( biological , social , behavioral , psychological ) and environmental ( East vs. West Germany , rural vs. urban regions ) characteristics in children . Methods Information on PA and potential correlates was collected from 1843 girls and 1997 boys using question naires during the 10-year follow-up of two prospect i ve birth cohort studies ( GINIplus and LISAplus ) . Study regions represent urban and rural sites as well as East and West of Germany . Logistic regression modeling was applied to examine cross-sectional associations between individual as well as environmental factors and  PA levels . Results Five of fourteen variables were significantly associated with  PA .  Among children aged 10 , girls tended to be less active than boys , especially with respect to vigorous PA ( OR = 0.72 for summer ) . Children who were not a member of a sports club showed a substantially reduced amount of PA in winter ( OR = 0.15 ) . Rural environments promote moderate PA  , particularly in winter ( OR = 1.88 ) , whereas an increased time outdoors primarily promotes moderate PA in summer ( OR = 12.41 ) . Children with abnormal emotional symptoms  exhibited reduced physical activity , particularly in winter ( OR = 0.60 ) . BMI , puberty , parental BMI , parental education , household income , siblings , TV/PC consumption , and method of arriving school , were not associated with PA . Conclusions When considering correlates of PA from several domains simultaneously , only few factors ( sex , sports club membership , physical environment , time outdoors , and emotional symptoms ) appear to be relevant . Although the causality needs to be ascertained in longitudinal studies , variables which can not be modified should be used to identify risk groups while modifiable variables , such as sports club activities , may be addressed in intervention programs OBJECTIVES To evaluate the relationship between changes in  physical activity ( PA ) , sedentary behavior , and physical self-perceptions and global self-worth in 30 , 8 - 12 years old , overweight/obese children ( 13 boys , 17 girls ) . METHODS Secondary analyses from a r and omized controlled trial design ed to increase PA and reduce sedentary behavior . PA was measured by accelerometers worn by participants every day for 8 weeks .  Sedentary behavior , defined as minutes per day spent in television viewing , was assessed by self-report . RESULTS Increases in PA were associated with increases in perceived physical conditioning ( r = .54 , p < .01 ) , body satisfaction ( r = .55 , p < .01 ) , and overall physical self-worth ( r = .44 , p < .05 ) independent of changes in body mass index ( BMI ) . Reductions in TV viewing were also related to increased physical and global self-worth . CONCLUSIONS Increases in PA are associated with improvements in physical self-perceptions but not global self-worth , while reductions in TV viewing are associated with increased physical and global self-worth , and these psychosocial benefits appear to be independent of changes in adiposity 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 Objective : To analyse the effect of extracurricular physical activities on fat mass accumulation and physical fitness during growth in early pubertal males . Design : Longitudinal study .Subjects : A total of 42 male children ( 9.4±1.4 years , Tanner I – II and 12.7±1.5 years , Tanner III – IV , before and after the 3.3 years follow-up , respectively ) , r and omly sample d from the population of Gran Canaria ( Spain ) , 26 of them physically active ( PA , at least 3 h per week during 3 years ) and 16 non-physically active ( non-PA ) . Measurements : Body composition ( dual-energy X-ray absorptiometry ) , anthropometrics ( body circumferences and skinfolds ) and physical fitness variables ( dynamic and isometric force , anaerobic capacity and maximal aerobic power ) were determined in all subjects . Results : Both groups had comparable body sizes at the start and the end of the study . Body mass index increased with growth more in the PA than in the non-PA group ( P<0.05 ) . However , fat mass accumulation with growth was lower in the PA than in the non-PA ( P<0.05 ) . There was a positive relationship between the increment of total and trunkal fat mass , especially in non-active children ( r 2=0.93 ) . In contrast , there was an inverse relationship between the total lean mass growth and the accumulation of total and regional fat mass ( r=−0.37 to −0.41 , all P<0.05 ) . Physical fitness was maintained in the PA , while it worsened in the non-PA children . Conclusions : Without any dietary intervention , children who regularly participate in at least 3 h per week of sports activities are more protected against total and regional fat mass accumulation . They also increase their total lean and bone mass to a greater extent than children who do not participate in extracurricular sport activities . In addition , PA children maintain their physical fitness during growth , while it deteriorates in the non-PA children This study examined the predictive validity of accelerometers ( ACC ) to estimate physical activity intensity ( PAI ) across age and differences in intensity predictions when expressed in relative and absolute PAI terms . Ninety adults categorized into 3 age groups ( 20 - 29 , 40 - 49 , and 60 - 69 yr ) completed a treadmill calibration study with simultaneous ACC ( 7164 Actigraph ) and oxygen-consumption assessment . Results revealed strong linear relations between ACC output and measured PAI ( R2 = .62-.89 ) across age and similar ACC cut-point ranges across age delineating absolute PAI ranges compared with previous findings . Comparing measured metabolic equivalents ( METs ) with estimated METs derived from previously published regression equations revealed that age did not affect predictive validity of ACC estimates of absolute PAI . Comparing ACC output expressed in relative vs. absolute terms across age revealed substantial differences in PAI ACC count ranges . Further work is warranted to increase the applicability ofACC use relative to PAI differences associated with physiological changes with age
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 .