***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 African-American girls are at increased risk for becoming overweight . Increased physical activity may prevent this . This study examines measurements of girls ' physical activity and associations with : BMI , parent 's reported self-efficacy and support for helping daughters be active , girl 's perceived support from parents for physical activity , parent 's and girl 's perceived neighborhood safety and access to facilities , and family environment . RESEARCH METHODS AND PROCEDURES Fifty-two 8- to 10-year-old African-American girls and their primary caregiver in the Minneapolis/St . Paul area participated in the Girls Health Enrichment Multisite Studies pilot intervention to prevent weight gain by promoting healthy eating and physical activity . Data collected included height , weight , physical activity level , and physical activity-related psychosocial measures from girl and parent . Girls wore an activity monitor for 3 days to assess activity level . Correlations were computed among the average minutes per day of moderate to vigorous activity between 12 pm and 6 pm and BMI and psychosocial measures . RESULTS BMI was inversely correlated with moderate to vigorous activity ( r = -0.35 , p < 0.01 ) , whereas parent 's self-efficacy for supporting daughter to be active was positively correlated with activity ( r = 0.45 , p < 0.001 ) . There was a trend for parent 's reported support of daughter 's activity level to be associated with activity ( r = 0.26 , p < 0.06 ) . Girl 's perception of parent 's support for physical activity , perceived neighborhood safety and access to facilities , and family environment were not associated with girl 's activity levels . DISCUSSION Interventions to increase physical activity among preadolescent African-American girls may benefit from a parental component to encourage support and self-efficacy for daughters ' physical activity BACKGROUND Underst and ing the determinants of physical activity in children is critical for the treatment and prevention of childhood obesity . Social-cognitive theory has been used to underst and behavioral patterns in children . OBJECTIVES To explore the relationship between health beliefs , self-efficacy , social support , and sedentary activities and physical  activity levels in children and to examine the relationship between physical activity and  children 's  self-esteem . METHODS Ninety-two children aged 10 to 16 years completed the study .  Physical activity was monitored for 1 week with a motion detector ( Actitrac ; IM Systems , Baltimore , Md ) . Moderate-level activity and high-level activity were defined based on the results of treadmill testing . Health beliefs , self-efficacy , social influences , and time spent in sedentary behaviors were determined through question naires . Self-esteem was measured using the Piers-Harris Children 's Self-Concept Scale . Chronic anxiety was measured with the Revised Children 's Manifest Anxiety Scale . RESULTS There was a significant decline in physical activity levels between ages 10 and 16 years , particularly in girls . Preteen girls spent approximately 35 % more time in low- and high-level activity than did teenage girls ( P<.001 ) . Overall , children spent 75.5 % of the day inactive , with a mean + /- SD of 5.2 + /- 1.8 hours watching television , sitting at the computer , and doing homework . In contrast , only 1.4 % of the day ( 12.6 + /- 12.2 minutes ) was spent in vigorous activity . Time spent in sedentary behaviors was inversely correlated with the amount of moderate-level activity ( P<.001 ) but not high-level activity . In contrast , time spent in high-level activity correlated with self-efficacy scores ( P<.001 ) and social influences scores ( P<.005 ) . High-level physical activity was also associated with improved self-esteem ( P<.05 ) . Higher health beliefs scores were not correlated with physical activity levels . CONCLUSIONS Children and adolescents are largely sedentary . Correlates of high- and low-level physical activity are different . Time spent on sedentary activities is inversely correlated with moderate-level activity , while self-efficacy and social influences are positively correlated with more intense physical activity . In addition , increased high-level physical activity is an important component in the development of self-esteem in children OBJECTIVE To develop and test a model based on B and ura 's social cognitive theory to predict healthy lifestyle behaviors for the prevention of osteoporosis . METHODS Participants were 354 girls , ages 8 - 11 years , recruited from area Girl Scout troops . Baseline data from a r and omized trial of behavioral interventions are presented . Measures of social support , knowledge , self-efficacy , dietary calcium intake , and weight-bearing physical activity ( WBPA ) were obtained via interviews and self-administered question naires . RESULTS A structural equation model was tested and fit the data well . Family social support , perceived self-efficacy for eating a calcium-rich diet , and knowledge of WBPA significantly predicted calcium intake . Friend and family support for exercise predicted WBPA . Self-efficacy partially mediated the relationship between family support and calcium intake , as confirmed by Holmbeck 's post-hoc probing strategy ( 2002 ) . CONCLUSIONS Suggestions are made for primary prevention interventions such as parent and peer involvement , health education , and problem-solving training OBJECTIVE To identify factors associated with changes in physical activity in adolescent girls at risk for sedentary lifestyles and obesity . DESIGN A cohort study was performed with 201 high school girls recruited to participate in an evaluation study of a school-based obesity prevention physical education program . Three assessment s were performed during an 8-month period . MAIN OUTCOME MEASURES Associations between physical activity and a range of personal factors ( self-acceptance , self-worth , athletic competence , body image , depressive mood , perceived benefits , enjoyment of physical activity , self-efficacy , and body mass index ) , behavioral factors ( watching television and time constraints )  , and socioenvironmental factors ( social support and costs/re sources )  were assessed . RESULTS The 2 strongest and most consistent factors associated with change in physical activity were time constraints and support for physical activity from peers , parents , and teachers . Measures assessing self-perceptions , global ( ie , self-worth ) and specific to physical activity ( ie , self-efficacy to be physically active ) , were also associated with change in physical activity . For example , a decrease of 2.0 U for an adolescent 's perceived time constraints ( possible range , 3.0 - 12.0 U ) would be expected to lead to an increase of 53 minutes of moderate to vigorous physical activity per week ( 95 % confidence interval , 33 - 72 minutes ) . An increase of 2.0 U in perceived support for physical activity ( possible range , 3.0 - 12.0 U ) would be expected to lead to an increase of 35 minutes of moderate to vigorous physical activity per week ( 95 % confidence interval , 13 - 56 minutes ) . An increase of 3.0 U on the self-worth scale ( possible range , 5.0 - 20.0 U ) might be expected to lead to an increase of 19 minutes of moderate to vigorous physical activity per week ( 95 % confidence interval , 0 - 40 minutes ) . CONCLUSION The effectiveness of interventions aim ed at increasing physical activity among adolescent girls might be enhanced by engaging support from friends , family , and caring adults ; addressing real and perceived time constraints ; and helping adolescent girls feel more confident about themselves and their ability to engage in physical activity OBJECTIVE This study compared correlates of  physical activity ( PA )  among African-American and white girls of different weight groups to guide future interventions . RESEARCH METHODS AND PROCEDURES Participants were 1015 girls ( mean age , 14.6 years ; 45 % African-American ) from 12 high schools in South Carolina who served as control subjects for a school-based intervention .  Post-intervention measures obtained at the end of ninth grade were used . PA was measured using the Three-Day PA Recall , and a question naire measured social-cognitive and environmental variables thought to mediate PA . Height and weight were measured , and BMI was calculated . Girls were stratified by race and categorized into three groups , based on BMI percentiles for girls from CDC growth charts : normal ( BMI < 85th percentile ) , at risk ( BMI , 85th to 94th percentile ) , and overweight ( BMI > or = 95th percentile ) . Girls were further divided into active and low-active groups , based on a vigorous PA st and ard ( average of one or more 30-minute blocks per day per 3-day period ) . Mixed-model ANOVA was used to compare factors among groups , treating school as a r and om effect RESULTS None of the social-cognitive or environmental variables differed by weight status for African-American or white girls . Perceived behavioral control and sports team participation were significantly higher in girls who were more active , regardless of weight or race group . In general , social-cognitive variables seem to be more related to activity in white girls , whereas environmental factors seem more related to activity in African-American girls . DISCUSSION PA interventions should be tailored to the unique needs of girls based on PA levels and race , rather than on weight status alone BACKGROUND Physical activity declines during childhood and determinants of this decline are poorly understood . The purpose of this prospect i ve study was to examine modifiable psychological and social correlates of physical activity change over 20 months . SUBJECTS 370 girls and 362 boys in public schools , studied through the 4th and 5th grade s. MEASURES A  physical activity index  was computed from child reports , parent reports , and objective activity monitoring . Predictor variables were assessed by child and parent surveys . RESULTS In multiple regressions , after adjustments for demographic variables , psychological variables explained 4 % of the variance in boys ' physical activity change , parent variables explained 8 % , and interactions with skinfolds explained 3 % , for a total of 15 % ( unadjusted ) . Regarding change in girls ' physical activity , psychological variables explained 3 % , parent variables explained 1.5 % , and interactions with skinfold explained 1.5 % , for a total of 6 % explained variance ( unadjusted ) . There were differences in predictors among children with high and low levels of body fat . CONCLUSIONS Children 's preferences for physical activity and frequency of parents transporting children to activity locations explained significant proportions of variance for girls and boys . The results support a dynamic model of the determinants of children 's physical activity , but most of the variance was left unexplained The goal was to have children and adolescents identify and rank the major perceived benefits of and barriers to healthful eating and physical activity and to suggest strategies for overcoming barriers . Semistructured , in-depth focus groups were undertaken using st and ardized questions and prompts . Students in grade s 2 through 11(ages 7 through 17 ; N=213 ) from 34 r and omly selected schools participated in 38 focus groups . Major benefits of healthful eating included improvements to cognitive and physical performance , fitness , endurance , psychological benefits , physical sensation ( feeling good physically ) , and production of energy . Barriers included convenience , taste , and social factors . Benefits of physical activity included social benefits , enhancement of psychological status , physical sensation , and sports performance . Barriers included a preference for indoor activities , lack of energy and motivation , time constraints , and social factors . Suggested strategies for overcoming barriers included support from parents and school staff , better planning , time management , self-motivation , education , restructuring the physical environment , and greater variety of physical activities Objective : To examine the extent to which parents and carers perceive injury and safety risks as serious enough to prevent or discourage their children , aged 5–12 years , from participating in sports/physical activity  and to identify factors that influence these perceptions The purpose of this study was to examine the effect of  parental involvement in a  school-based program about exercise and nutrition .  One fifth grade and one sixth grade class were r and omly assigned to each of the three different treatment conditions , a  school- and -home condition ( n = 45 ) , a  school-only condition  ( n = 43 ) , and a control condition  ( n = 44 ) . In the school- and -home condition , the children 's parents were also asked to participate in nutritional and exercise activities at home as a family " home team . " A multivariate analysis of variance on change scores was completed on the following variables : height , weight , skinfold , sit- and -reach , sit-ups , mile run , exercise knowledge , saturated fat , cholesterol , percent calories from fat , percent calories from carbohydrates , and nutrition knowledge . There was a significant difference among groups . The school- and -home and school-only groups showed significantly greater improvement than the control group but were not significantly different from each other . Univariate analyses on posttest scores indicated that the school- and -home children scored significantly higher than the control group on sit- and -reach flexibility and nutrition knowledge . The results indicate that including the family was primarily effective in facilitating children 's improvements in flexibility and nutrition knowledge rather than in diet and exercise behaviors 
    Output:
    
The majority of studies demonstrated positive associations among selected measures of parental tangible and intangible social support and youth activity .
Overall , parental social support demonstrated positive effects .