***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: OBJECTIVES We sought to determine the association between school- and neighborhood-level characteristics and physical activity among young people . METHODS We collected the data as part of Youth'07 , a nationally representative survey of the health and well-being of high school students in New Zeal and . In total , 9107 students from 96 schools participated ( 63 % response rate ) . Students answered questions about their schools ( e.g. , support for physical activity ) and neighborhoods ( e.g. , community cohesion , disintegration , safety , and recreational facilities ) . We created school-level measures by aggregating the students ' reports within their schools and we created neighborhood-level measures by aggregating the students ' reports of their neighborhoods to the census area unit of their residential address . We conducted analyses by using cross-classified r and om-effects models controlling for individual variables , with school and neighborhoods treated as r and om effects . RESULTS Schools characterized by high sports team participation and neighborhoods characterized by high social connections were positively associated with student physical activity . We observed few other significant characteristics of school and neighborhood environments . CONCLUSIONS Our findings highlight that opportunity for sports participation and strong social connections in neighborhoods are particularly important for youths ' physical activity BACKGROUND Our objective was to evaluate the effects of environmental , policy , and social marketing interventions on physical activity and fat intake of middle school students on campus . DESIGN Twenty-four middle schools were r and omly assigned to intervention or control conditions . Baseline measures were collected in spring 1997 , and interventions were conducted during the 1997 - 1998 and 1998 - 1999 school years SETTING /PARTICIPATION : The schools had mean enrollments of 1109 , with 44.5 % nonwhite students . Over 2 years , physical activity interventions were design ed to increase physical activity in physical education classes and throughout the school day . Nutrition interventions were design ed to provide and market low-fat foods at all school food sources , including cafeteria breakfasts and lunches , a la carte sources , school stores , and bag lunches . School staff and students were engaged in policy change efforts , but there was no classroom health education . MAIN OUTCOMES MEASURES Primary outcomes were measured by direct observation and existing records . RESULTS R and omized regression models ( N = 24 schools ) revealed a significant intervention effect for physical activity for the total group ( p < 0.009 ) and boys ( p < 0.001 ) , but not girls ( p < 0.40 ) . The intervention was not effective for total fat ( p < 0.91 ) or saturated fat ( p < 0.79 ) . Survey data indicated that the interventions reduced reported body mass index for boys ( p < 0.05 ) . CONCLUSIONS Environmental and policy interventions were effective in increasing physical activity at school among boys but not girls . The interventions were not effective in reducing fat intake at school . School environmental and policy interventions have the potential to improve health behavior of the student population , but barriers to full implementation need to be better understood and overcome Background Regular physical activity is associated with a range of physical and psychological health benefits . In North America the majority of adolescents are insufficiently active . Purpose The purpose of this study was to examine the prospect i ve relationship between adolescents ' perceptions of transformational leadership displayed by their  school physical education teachers  and their own physical activity behaviors , both with respect to within-class physical activity ( WCPA ) and also leisure time physical activity ( LTPA ) . Method The study used a prospect i ve observational design . Using multilevel structural equation modeling ( MSEM ) , we examined the extent to which adolescents ' affective attitudes mediated the effects of teachers ' behaviors on adolescents ' physical activity responses . Two thous and nine hundred and forty-eight adolescents ( Mage = 14.33 , SD = 1.00 , Nfemale = 1,641 , 55.7 % ) from 133 Grade 8–10 classes in British Columbia ( Canada ) provided ratings of their physical education teachers ' behaviors midway through the school year . Two months later , students completed measures of affective attitudes , WCPA , and LTPA . Results The results indicated that adolescents ' perceptions of transformational teaching explained significant variance in both WCPA and LTPA , and these effects were fully mediated by adolescents ' affective attitudes ( total indirect effect : b = 0.581 , p < 0.001 ) . Conclusion The findings suggest that transformational leadership behaviors displayed by physical education teachers may be an important source of adolescent enjoyment of physical education as well as health-enhancing physical activity involvement within school and outside of school PURPOSE To examine the relationship between role model presence , type of role model , and various health-risk and health-protective behaviors among California adolescents . METHODS We used cross-sectional data on 4,010 multiethnic adolescents aged 12 - 17 years from the 2003 California Health Interview Survey , a population -based r and om-digit dial telephone survey of more than 40,000 California households . The survey , conducted every other year since 2001 , collects extensive demographic , health , and health-related information . RESULTS Fifty-nine percent of adolescents identified a role model . Affluent teens were more likely to have a role model than lower income teens . Role models were generally of the same ethnicity and gender as the teens ; ethnic congruence was higher among African Americans and whites than Latinos and Asians ; gender congruence was higher among males . Type of role model was significantly associated with health-related behaviors . Identification of a teacher was strongly associated with positive health behaviors . Correlations with health-promoting behaviors were generally smaller in magnitude but consistently positive among family member and athlete role models . Peer or entertainer role models were associated with health-risk behaviors . CONCLUSION Not only role model presence but also the type of role model is an important predictor of  adolescent health-related behaviors . Our findings have implication s for design ing youth targeted interventions and policies involving role models Within instructional setting s , individuals form relational efficacy appraisal s that complement their self-efficacy beliefs . In high school physical education ( PE ) , for instance , students develop a level of confidence in their teacher 's capabilities , as well as estimating how confident they think their teacher is in their ( i.e. , the students ' ) ability . Grounded in existing trans context ual work , we examined the motivational pathways through which students ' relational efficacy and self-efficacy beliefs in PE were predictive of their leisure-time physical activity . Singaporean students ( N = 990 ; age M = 13.95 , SD = 1.02 ) completed instruments assessing efficacy beliefs , perceptions of teacher relatedness support , and autonomous motivation toward PE , and 2 weeks later they reported their motivation toward , and engagement in , leisure-time physical activity . Structural equation modeling revealed that students reported stronger other-efficacy and RISE beliefs when they felt that their teacher created a highly relatedness-supportive environment . In turn , their relational efficacy beliefs ( a ) supported their confidence in their own ability , ( b ) directly and indirectly predicted more autonomous motives for participation in PE , and ( c ) displayed prospect i ve trans context ual effects in relation to leisure-time variables . By emphasizing the adaptive motivational effects associated with the tripartite constructs , these findings highlight novel pathways linking students ' efficacy perceptions with leisure-time outcomes Objective To examine associations between students ’ time spent in  moderate to vigorous physical activity ( MVPA )  and the school built environment while also considering features of the schools ’ social environment and student-level characteristics . Methods Using surveys and GIS measures , multilevel linear regression analysis was applied to examine the environment- and student-level characteristics associated with time spent in MVPA  among grade 9–12 students ( n = 22,117 ) attending 76 secondary schools in Ontario , Canada as part of the SHAPES-Ontario study . Results Statistically significant between-school r and om variation in student MVPA was identified [ $ $ \sigma^{2}_{\mu 0 } $ $ = 9,065.22 ( 250.64 ) ] ; school-level differences accounted for 3.0 % of the variability in student MVPA .  Students attending a school that offered daily physical education or provided an alternate room for physical activity spent more time in MVPA than students attending a school without these re sources . Moreover , as l and -use mix diversity and walkability of the school neighbourhood increased , students ’ time spent in MVPA decreased . Conclusion Developing a better underst and ing of the environment- and student-level characteristics associated with students ’ time spent in MVPA is critical for informing school-based physical activity intervention programmes and policies PURPOSE School physical education ( PE ) is highly recommended as a means of promoting physical activity , and r and omized studies of health-related PE interventions in middle schools have not been reported . We developed , implemented , and assessed an intervention to increase physical activity  during middle-school PE classes . METHODS Twenty-four middle schools ( approximately 25,000 students , 45 % nonwhite ) in Southern California participated in a r and omized trial . Schools were assigned to intervention ( N = 12 ) or control ( N = 12 ) conditions , and school was the unit of analysis . A major component of the intervention was a 2-yr PE program , which consisted of curricular material s , staff development , and on-site follow-up . Control schools continued usual programs . Student activity and lesson context were observed in 1849 PE lessons using a vali date d instrument during baseline and intervention years 1 and 2 . RESULTS The intervention significantly ( P = 0.02 ) improved student moderate to vigorous physical activity ( MVPA ) in PE , by approximately 3 min per lesson . Effects were cumulative ; by year 2 intervention schools increased MVPA by 18 % . Effect sizes were greater for boys ( d = 0.98 ; large ) than girls ( d = 0.68 ; medium ) . CONCLUSIONS A st and ardized program increased MVPA in middle schools without requiring an increase in frequency or duration of PE lessons . Program components were well received by teachers and have the potential for generalization to other schools . Additional strategies may be needed for girls Based on self-determination theory , the present study developed and evaluated the utility a school-based intervention to change pupils ’ physical activity intentions and self-reported leisure-time physical activity behaviour . The study evaluated utility of the intervention to promote physical activity participation over a 5-week interval of time . A cluster r and omised design targeting 215 pupils from 10 schools with schools as the unit of r and omisation was adopted ( Male = 106 , Female = 109 , Age = 14.84 , SD = 0.48 ) . Results indicated that pupils who were taught  by autonomy-supportive teachers reported stronger intentions to exercise during leisure time and participated more frequently in leisure-time physical activities than pupils in the control condition . Autonomous motivation and intentions mediated the effects of the intervention on self-reported physical activity behaviour . It is concluded that self-determination theory provides a useful framework for the development of school-based interventions that ultimately affect leisure-time physical activity participation The Healthy Youth Places ( HYP ) intervention targeted increased fruit and vegetable consumption ( FV ) and physical activity ( PA ) through building the environmental change skills and efficacy of adults and youth .  HYP included group training for adult school site leaders , environmental change skill curriculum , and youth-led FV and PA environment change teams . Sixteen schools were r and omized to either implement the HYP program or not . Participants ( N = 1,582 ) were assessed on FV and PA  and hypothesized HYP program mediators ( e.g. , proxy efficacy ) at the end of sixth grade ( baseline ) , seventh grade ( Postintervention Year 1 ) , and eighth grade ( Postintervention Year 2 ) . After intervention , HYP schools did not change in FV but did significantly change in PA compared to control schools . Proxy efficacy to influence school PA environments mediated the program effects . Building the skills and efficacy of adults and youth to lead school environmental change may be an effective method to promote youth PA The relationship between the school environment and health has infrequently been examined . This study sought to examine the association between school students ' perceptions of their school environment , teachers ' and peers ' support and their health behaviours . A cross sectional descriptive survey by supervised self-administration was conducted in 1996 based on the international WHO collaborative survey of school children 's health and lifestyle ( the HBSC Study ) and extended in an Australian setting . R and omly sample d primary and secondary schools from Catholic , Independent and Government education sectors throughout New South Wales ( NSW ) , Australia , were invited to participate . The final sample included 3918 school students attending Year 6 ( primary school ) , Year 8 and Year 10 ( high school ) from 115 schools . The main outcome measures were self-reported health status and 7 health behaviours ( tobacco use , alcohol use , physical activity , dental hygiene , nutritional intake , seat belt and bicycle helmet use ) . Independent variables included student perceptions of the school environment , perceptions of teachers ' and peers ' support .  Girls , Year 6 students and students who have less than $ 19 a week to spend were significantly more likely to have positive perceptions towards their school environment , teacher(s ) and peers . Students who had positive perceptions regarding their school environment and perceived their teachers as supportive were significantly more likely to engage in health promoting behaviours adjusting for age , sex and average weekly pocket money . A supportive peer environment was not associated with positive health behaviour . Health promotion practitioners need to consider the impact of the school environment on health behaviours of school students . In particular , practitioners should consider intervention models that improve the school environment as a key strategy within a health promoting school Objective : To assess developmental trends in physical activity and sedentary behaviour in British adolescents in relation to sex , ethnicity and socioeconomic status ( SES ) . Design : A 5-year longitudinal study of a diverse cohort of students aged 11 
    Output:
    
A range of school-based policy ( e.g. break time length ) , physical ( e.g. facilities ) and social-environmental ( e.g. teacher behaviours ) factors were associated with adolescent physical activity , with limited research on sedentary behaviour .
The mixed- studies synthesis revealed the importance of specific activity setting s ( type and location ) and intramural sport opportunities for all students .
Important physical education-related factors were a mastery-oriented motivational climate and autonomy supportive teaching behaviours .
Qualitative evidence highlighted the influence of the wider school climate and shed light on complexities of the associations observed in the quantitative literature .