regular physical activity ( pa ) reduces the risk of chronic disease , including some 
                 types of cancer , diabetes , obesity and cardiovascular disease ( 1 ) . despite this evidence ,
pa levels 
                 continue to be far from ideal in most parts of the world ( 2 ) . of special concern
is the evidence 
                 indicating that children , particularly in the developed world , establish a sedentary 
                 lifestyle early in life ( 3 ) .
some developing countries are experiencing similar patterns associated 
                 with lifestyle changes , such as sedentary habits and high caloric intake that 
                 contribute in part to the worldwide obesity epidemic ( 4 ) .
the latin american region is 
                 experiencing increasing rates of obesity among youth ( 59 ) . in developing countries ,
high prevalence 
                 of overweight and obesity lead to early mortality in adulthood ( 10 ) .
children today have fewer opportunities to be active in a safe and independent 
                 manner , especially in large cities in developing countries that are rapidly 
                 urbanizing ( 11 ) . 
                 according to a birth cohort study conducted in pelotas , brazil , the prevalence of 
                 sedentary lifestyles , characterized by excessive tv viewing and lack of pa , among 
                 youth is as high as 58% ( 12 ) .
factors that decrease energy 
                 expenditure , such as the declining time for physical education ( pe ) in schools , may 
                 play an important role in the prevalence of overweight among children .
because 
                 students spend large amounts of time in school , there is a great potential for 
                 increasing their level of pa through school - based interventions ( 13,14 ) . in a systematic review of 14 
                 evidence - based pa promotion strategies , the us
guide to community preventive 
                     services ( community guide ) found strong supporting 
                 evidence that school - based pe programs increased pa among school children ( 15 ) .
the school - based pe 
                 interventions included modified pe classes , generally with more classroom time and 
                 more moderate - to - vigorous pa ( 16 ) .
the recommendations of the community guide and its process of 
                 systematic review have not yet been systematically examined and applied in 
                 developing countries .
many promising pa interventions are being carried out in latin 
                 america ( 17 ) ; however , 
                 their effectiveness has generally not been evaluated .
the guide for useful 
                 interventions for activity in latin america ( guia ) was initiated in 2005 to examine 
                 and promote evidence - based strategies , with the intention of increasing pa in latin 
                 america ( 18 ) .
the purpose 
                 of the initial phase of guia was to conduct a review of the latin american 
                 literature on community - based pa promotion strategies and to determine the 
                 applicability of the community guide recommendations in this 
                 region . according to community guide criteria
, 
                 school - based pe was found to be the only type of pa intervention with a strong 
                 enough body of evidence to make a practice recommendation ( 18 ) .
this article focuses on the results of 
                 the guia systematic review related to school - based pe programs in latin america .
the 
                 aims of the article are to ( i ) describe selected school - based pe interventions from 
                 the guia review ; ( ii ) discuss implications of effective school - based pe 
                 recommendations in the latin america region ; ( iii ) propose approaches for 
                 implementing these interventions in latin america ; ( iv ) identify gaps in the 
                 research literature related to pa promotion in latin american youth .
although this article focuses specifically on the school - based pe findings of the 
                 guia literature review , the method used to search , categorize and abstract the 
                 papers for the present study were the same used in the overall review .
therefore , in 
                 order to understand the process of reviewing and evaluating the latin america 
                 literature related to pa interventions , it is necessary to review the methods 
                 previously described ( 18 ) .
first , five databases of peer - reviewed literature and brazilian theses 
                 were systematically searched for studies of pa community interventions by using 
                 search terms in portuguese , spanish and english .
intervention studies were then 
                 synthesized in one - page summary tables , categorized by the 14 community 
                     guide pa intervention categories ( 16 ) and screened for inclusion in a full 
                 abstraction process .
this process followed the community guide 
                 procedures ( 19 ) , with 
                 some modifications ( 18 ) . 
                 on the basis of previously described criteria ( 15 ) ,
studies were evaluated by two 
                 measures : design suitability ( classified as greatest , moderate and least [ appendix 
                 1 ] ) and quality of intervention execution ( classified according to the number of 
                 limitations to assess the strength of the evidence [ appendix 2 ] ) .
relative effect sizes for the school - based pe intervention studies were calculated as 
                 the net percentage change from baseline for all reported measures of aerobic 
                 capacity and physical activity levels and for all time periods .
the formula for 
                 calculating the net effect ( figure 
                     1 ) varied depending on the study design  with or without a 
                 control group or pre - intervention outcome measurement ( 16 ) . to identify common characteristics of 
                 the school - based pe interventions , the authors reviewed each of the school - based pe 
                 articles and abstraction forms in detail , categorizing and listing intervention 
                 components .
core components were determined according 
                 to frequency of use by most of the studies and also by taking into account the 
                 intervention activities recognized by the community guide ( 16 ) . additionally , brazilian experts provided input to address issues related to pe 
                 typically not available in the literature .
these experts made available additional 
                 literature sources , such as peer - non - reviewed manuscripts and meeting reports , not 
                 included in the evidence - based review .
the systematic literature review yielded five school - based pe intervention studies 
                     ( 2024 ) , out of six that met 
                 all of the inclusion criteria ( 18 ) .
the excluded study was a duplicate of one included thesis ( 20 ) , which contained more 
                 details about the intervention and evaluation for the abstraction process than the 
                 peer - reviewed article .
all five studies had sufficient quality of design , execution 
                 and detail regarding the intervention and outcomes to undergo the second phase of 
                 the abstraction process .
three studies used randomized group design ( 20,21,23 ) and two used a non - randomized group 
                 design with a concurrent comparison group ( table 1 ) ( 22,24 ) .
one study was conducted in elementary 
                 public schools in brazil ( children aged 710 years ) ( 20 ) , two were carried out 
                 in public schools in chile ( first- through ninth - grade classes ) ( 21,22 ) and the remaining two took place in us 
                 elementary schools mainly attended by latino students and located on the us / mexico 
                 border ( 23,24 ) .
two studies ( 23,24 ) reported minutes spent 
                 in moderate and vigorous pa , and one study ( 20 ) reported four different outcomes 
                 related to behavior : percentage of children biking or walking to school , estimated 
                 energy expenditure based on observed pa behavior of children , percentage of children 
                 who were very active during pe classes and percentage of time spent walking during 
                 pe classes . further reported outcomes were aerobic capacity as estimated by maximal 
                 oxygen uptake ( vo2 max ) ( 21 ) , results from timed runs ( 23 ) or endurance testing 
                 ( shuttle runs ) ( 22 ) .
although the outcomes , ascertainment methods , and duration of interventions varied 
                 between studies , there were consistent positive increases in pa levels for all 
                 outcomes measured during pe classes ( relative net effects ranged from 7% 
                 to 307% ) in all three randomized studies ( 20,21,23 ) ( figure 1 ) .
the extreme magnitude of the 
                 307% net effect is explained by the low baseline walking levels in the 
                 intervention group versus the control group ( 5.6 vs. 14.4% , 
                 respectively ) . at post - test
the intervention group increased time spent walking 
                 during pe classes nearly 56 times that of baseline , while the control 
                 group increased walking time by only 1.5 times baseline .
likewise , endurance ( 23 ) and active 
                 transportation to school ( 20 ) outcomes showed small but positive net effects for the same group of 
                 studies . with the exception of one cohort in heath ( 24 ) , the non - randomized studies increased 
                 moderate and vigorous pa levels during pe classes .
these increases ranged from 
                 5% to 69% for moderate and 50% to 55% 
                 for vigorous pa levels during pe classes .
the results from the shuttle run test 
                     ( 22 ) demonstrated 
                 increased endurance performances among boys ( 35% ) and girls 
                 ( 37% ) . after reviewing the details of each study ( table 1 ) ,
four types of intervention 
                 activities were identified and summarized as the  core 
                 components presented in table 2 .
core components included the 
                 provision of information about the benefits and importance of health and active 
                 living ( 20,22 ) ; types of pa suitable 
                 for a particular age range ( 20 ) ; overall pe class planning ( lesson plan development , class and 
                 environment management ) and methods of pa practice ( 23,24 ) ; increases in the duration of the 
                 already scheduled pe classes ( 23,24 ) ; 
                 addition of extra pe classes per week ( 21,22 ) ; use of age - specific and enjoyable 
                 activities ( 2024 ) ( such as balance exercises , dancing , jumping , and running ) ; availability 
                 of new materials for classes ( balls , basketball boards ) ( 2022 ) ; and adaptable , flexible and culturally 
                 sensitive activities based on ethnicity or socioeconomic status ( 20,2224 ) .
characteristics of the five school - based intervention abstracted studies core components summarized from the five intervention studies .
our results identified several common characteristics , the core components ( table 2 ) , of successful 
                 school - based pe interventions in latin america that were comparable to some of those 
                 used in the community guide .
these included the addition of 
                 supplementary pe classes , the lengthening of existing pe classes , and an increase in 
                 time spent in moderate and vigorous pa without necessarily changing duration of pe 
                 classes ( 16 ) .
four ( 20,2224 ) out of the five studies reviewed in the 
                 current study were adaptations of north american school - based interventions and 
                 therefore delivered analogous activities to the 13 studies reviewed by the 
                     community guide , both in terms of content and quality . with 
                 appropriate adjustments for national , local , and cultural contexts ,
the identified 
                 core components from interventions from two schools in chile , a brazilian elementary 
                 school and two elementary schools on the us / mexican border could be a logical 
                 approach to guide pe recommendations and implementation across diverse countries , 
                 cultures and populations such as those found in latin america .
high - quality school - based pe programs , combining all or some of the core components 
                 described here , increase pa among children in latin america in the same way as they 
                 do in the usa ( 18 ) . 
                
similar to the guia literature review ( 18 ) , the 13 us qualifying studies revealed 
                 consistent increases in time spent in pa at school ( 16 ) , the net increase in the amount of pe 
                 class time spent in moderate and vigorous pa was 50% , ranging from 
                 6% to 125% .
the percentage of class time increase in moderate 
                 and vigorous pa was 10% , ranging from 3% to 15% , 
                 although one study reported a 762% increase from a very small baseline 
                 value .
two studies showed increases in energy expenditure , and 11 studies reported 
                 increases in aerobic capacity with a median of 8% ( interquartile range 
                 3% to 19% ) ( 16 ) . when comparing intervention effects for the same outcomes , the five studies from the 
                 present study are generally consistent with the us cg results , both 
                 in direction and effect size .
some of the us cg net effects also 
                 had a wide range , particularly for the amount and percentage of pe class time spent 
                 in moderate and vigorous pa .
the three studies that reported increased levels of pa 
                 during pe class ( 20,23,24 ) used the same observational method 
                     ( 16 ) to measure the 
                 amount of pe class time spent in moderate and vigorous pa , but for different outcomes , such as the time spent being very active and 
                 the amount of walking during pe classes ( 20 ) .
the wide range in net effect sizes 
                 reflects differences in the degree of change in the outcome measures for 
                 intervention and comparison ( if applicable ) groups before and after the 
                 intervention .
they also reflect the magnitude of the pre - intervention measures ( see 
                     figure 1 note ) .
insufficient evidence supported recommending classroom - based health education to 
                 increase pa , mainly because of an insufficient number of qualified studies 
                     ( n = 3 ) ( 18 ) .
these interventions consist of multicomponent health education classes 
                 in elementary , middle , or high schools that aim to help students to develop the 
                 skills they need to make rational decisions about adopting healthier behaviors 
                     ( 16 ) .
net percentage change in physical activity from baseline for the school - based 
                         physical education intervention studies source : adapted from kahn e , ramsey l , brownson r , et al .
am j prev med . 2002 ; 22(4 ) : 73107 . among the three reviewed studies ,
the net effects for various outcomes ( e.g. 
                 frequency of exercise - related behaviors , any moderate and vigorous pa in the 
                 previous week ) ranged from 0.0 to 0.2 ; net effects for 11 of the 14 outcomes were 
                 between 0 and 0.1 .
these net effects tended to be much lower in magnitude than those 
                 observed for the school - based pe interventions , which suggests that merely providing 
                 health information and promoting behavioral skills for healthy decision - making may 
                 be insufficient to significantly change pa behavior .
however , more research of 
                 classroom - based health education , both in the usa ( 16 ) and in latin america , is needed to 
                 confirm this finding .
the impact of an intervention is determined not only by its reach and efficacy but 
                 also by the extent to which the intervention is adopted , implemented as intended and 
                 maintained at the system and individual level ( 25 ) .
an effective intervention needs to 
                 have broad reach and be feasible to implement in  real - world 
                 settings in order to make a public health impact ( 25 ) .
some of the major challenges for 
                 interventions are finding creative and cost - effective ways to implement 
                 evidence - based programs and policies at the population level , while providing 
                 adequate information and resources ( e.g. infrastructure , training , proper economic 
                 and social environments ) ( 26 ) .
this is particularly important in a region where legislation to promote 
                 school - based pe is highly variable .
in addition , it is key to consider differences 
                 in terms of social influences that may affect children 's and 
                 adolescents behavior ( e.g. family , social networks , culture ) when 
                 adapting programs that are effective in a specific setting or population ( 27 ) .
although the purpose 
                 of school - based pe is larger than enhancing physical fitness only , it also has great 
                 potential for pa promotion because of its effectiveness in increasing pa among 
                 children ( 18 ) and because 
                 school programs reach virtually all children at relatively low cost with preexisting 
                 infrastructure . in a context of increased academic and political credibility for pa promotion and pe 
                 during the past decade ( 28 ) , supportive school pe policies appear to exist in many latin american 
                 countries ( 29,30 ) . in these countries , 
                 even though pe is mandatory for students in public and private elementary and 
                 secondary schools , the requirements concerning frequency and duration of classes is 
                 generally low ( 31 ) .
an 
                 optimal pe curriculum should include a variety of learning and practice experiences 
                 that will provide the basis for active living in the adult years ( 32 ) .
however , according to 
                 experts in the area , pe programs in latin america are often of low quality and 
                 quantity .
therefore , a comprehensive school policy to increase pa practice during 
                 school - based pe and enhance its quality is required .
in addition , frequency and 
                 duration of classes is often less than optimal because of challenges related to 
                 salary , work environment , physical space and curriculum structure ( 31 ) ; consequently , barriers 
                 to implementation exist primarily within the school systems and need to be addressed 
                 as well . according to melo ( 28 ) , 
                
there is a call for academic institutions where pe teachers are trained to push for 
                 an adequate transition from what is learned in the academic world to what is needed 
                 in everyday practice in the schools .
often , the fields of academic knowledge 
                 production ( e.g. universities / research institutes ) and policy 
                 formulation / implementation are very different , frequently with incompatible goals 
                 and methods ( 33 )
. 
                 therefore , collaborative partnerships between researchers and practitioners , along 
                 with regulatory and legislative enforcement and political commitment and support for 
                 pe , are particularly desirable to help bridge the gap between theory and practice 
                 and for successful and sustainable program implementation
the five identified studies 
                 applied diverse ways to measure similar or same outcomes ( e.g. moderate and vigorous 
                 pa levels during pe classes ) , which limited the ability of the previous review to 
                 derive a summary measure for the effect of school - based pe across the five reviewed 
                 studies .
the net effect plot is an effort to be transparent in illustrating the 
                 variability in measures and lack of a gold standard in pa measurement in kids . by 
                 computing the net intervention effect
although the literature search was conducted to identify interventions 
                 delivered in latin america , we discuss findings from only five studies , two of which 
                 were implemented on the us / mexican border ( 23,24 ) .
however , because these interventions 
                 took place in schools attended mainly by hispanic children of low socioeconomic 
                 status , and since information on quality or availability of equipments and 
                 facilities was not available in the reviewed papers , we considered this population 
                 and setting comparable to those from other latin american countries .
the three 
                 remaining studies were limited to chile ( 21,22 ) and brazil ( 20 ) .
this limitation should be taken into 
                 account when disseminating school - based pe interventions in latin america
. another 
                 consideration is the variability in the interventions duration ( 4 months 
                 to 3 years ) .
the two longest studies ( 23,24 ) are funded adaptations of a broad , 
                 well - designed , tested and documented intervention study , which could justify in part the length of these two interventions .
the 
                 three remaining studies ( 2022 ) were much less supported and were single initiatives largely developed 
                 by academic institutions ( university of chile , catholic university of chile and 
                 federal university of sao paulo ) in collaboration with local health or education 
                 sectors .
nevertheless , the two longest interventions ( 23,24 ) did not result in larger net effect for 
                 similar outcomes when compared with the study with shortest duration ( 20 ) .
identifying interventions to increase pa levels in school settings is particularly 
                 important in latin america because of the rapid demographic , epidemiologic and 
                 nutritional transitions associated with the increase in risk factors for chronic 
                 disease , including obesity and physical inactivity ( 4 ) .
these problems are unequally distributed 
                 across populations , and they disproportionately affect the most impoverished latin 
                 americans .
given the limited literature on evidence - based interventions for pa 
                 promotion in latin american countries , developing recommendations to address 
                 physical inactivity among youth is essential .
the five studies in the guia review ( 18 ) and the 13 studies from the 
                     community guide review ( 16 ) were of sufficient quality to be 
                 included in the evidence - based review process and form the basis for the 
                 recommendation of school - based pe for pa promotion among children and adolescents in 
                 latin america .
even though this may appear to be a small number of studies upon 
                 which to base global public health policy , relatively few other public health 
                 intervention recommendations are supported by systematic reviews of the scientific 
                 literature ( 27 ) .
further 
                 implementation of school - based pe interventions could greatly benefit from 
                 systematic evaluation and publication of peer - reviewed studies on 
                 schools pe efforts to promote pa .
given the importance of promoting pa in youth to improve the health of latin 
                 americans , our results provide the impetus to implement high - quality school - based pe 
                 interventions in this region .
enhancing the quality of pe in the schools and 
                 increasing the level of pa among youth depends on capacity building and training for 
                 pe teachers and instructors , appropriate changes in the pe curricula , proper 
                 infrastructure including equipment and materials , and adjustments to various 
                 political , cultural and socioeconomic characteristics .
additionally , future research 
                 is needed to identify other practical key elements , such as legislation , policy , 
                 barriers and facilitators for promoting school - based pe in latin america .
the findings and conclusions in this report are those of the authors and do not 
                 necessarily represent the official position of the centers for disease control and 
                 prevention .
 this article focuses on results of the systematic review from the guide for 
                     useful interventions for activity in latin america project related to 
                     school - based physical education ( pe ) programs in latin america . 
 the aims of the 
                     article are to describe five school - based pe programs from latin america , 
                     discuss implications for effective school - based pe recommendations , propose 
                     approaches for implementing these interventions , and identify gaps in the 
                     research literature related to physical activity promotion in latin american 
                     youth . following the us community guide systematic review 
                     process , five school - based pe intervention studies with sufficient quality of 
                     design , execution and detail of intervention and outcomes were selected for full 
                     abstraction . 
 one study was conducted in brazil , two studies were conducted in 
                     chile and two studies were conducted on the us / mexico border . while studies 
                     presented assorted outcomes , methods and duration of interventions , there were 
                     consistent positive increases in physical activity levels for all outcomes 
                     measured during pe classes , endurance and active transportation to school in all 
                     three randomized studies . 
 except for one cohort from one study , the 
                     non - randomized studies showed positive intervention effects for moderate and 
                     vigorous physical activity levels during pe classes . 
 the core elements of these 
                     five interventions included capacity building and staff training ( pe specialists 
                     and/or classroom teachers ) ; changes in the pe curricula ; provision of equipment 
                     and materials ; and adjustment of the interventions to specific target 
                     populations . in order to translate the strong evidence for school - based pe into 
                     practice , systematic attention to policy and implementation issues 
 is required . 
                     
 ( global health promotion , 2010 ; 17(2 ) : pp . 0515 ) 
Introduction
Methods
Results
Discussion
Conclusions
Disclaimer