Children's physical activity in family child care homes: Influence of quality status, environment and policy features, and child characteristics.

BACKGROUND: About half of preschool-age children are not meeting recommendations of 15 min/h of physical activity (PA), and nearly one out of seven children between the ages of 2-5 years are living with obesity. Furthermore, children attending family child care homes (FCCHs), compared with larger child care centers, engage in lower levels of PA and appear to be at a higher risk of obesity. Therefore, examining PA and multi-level factors that influence PA in children who attend FCCHs is essential. METHODS: The Childcare Home Eating and Exercise Study (CHEER) examined PA behaviors of 184 children enrolled in 56 FCCHs and FCCH quality status, environment and policy features, and child characteristics. PA was assessed by accelerometer, and FCCH environment and policy was assessed via structured observation. Multiple linear regression was used to model associations between school day total PA and FCCH quality status, environment and policy features, and child characteristics. RESULTS: Child participants were on average 3.1 years old; participants were non-Hispanic Black (47.3%), Non-Hispanic White (42.9%), other race/ethnicity (7.1%), and Hispanic/Latin (2.7%). Children in FCCH settings participated in 11.2 min/h of total PA, which is below the recommended 15 min per hour. The PA environment and policy observation yielded a score of 11.8 out of a possible 30, which is not supportive of child PA. There were no associations between total child PA and FCCH quality status, environment and policy features, and child characteristics in these FCCH settings. CONCLUSIONS: This study was unique in its examination of PA and a comprehensive set of factors that may influence PA at the individual, organizational, environmental, and policy levels in a diverse sample of children attending FCCHs in South Carolina. Additional research is needed to better understand how to increase children's physical activity while they are in the FCCH setting. This research should use multi-level frameworks and apply longitudinal study designs.

Young Children's Dietary Quality in Family Child Care and in Their Own Home.

BACKGROUND: Some evidence suggests that children may have higher quality dietary intake in early care and education settings, compared with their respective homes, but no studies have explored these differences among children in less formal family child care. OBJECTIVE: The purpose of this study was to compare dietary quality via the Healthy Eating Index 2015 among children in family child care and in their own home. DESIGN: This was a cross-sectional analysis of baseline dietary intake data from the Childcare Home Eating and Exercise Research study, a natural experiment, using directly observed dietary data in child care and 24-hour recall data in homes among children in South Carolina. PARTICIPANTS/SETTING: Participants were 123 children in 52 family child-care homes between 2018 and 2019. MAIN OUTCOME MEASURE: The main outcome was total and component Healthy Eating Index 2015 scores. STATISTICAL ANALYSIS: The analysis was a hierarchical linear regression of children nested within family child care homes adjusting for child, provider, facility, and parent characteristics, including sex, age, race, ethnicity, and income, with parameters and SEs estimated via bootstrap sampling. RESULTS: Children had a mean ± SD Healthy Eating Index 2015 score of 60.3 ± 12.1 in family child-care homes and 54.3 ± 12.9 in their own home (P < 0.001). In adjusted analysis and after accounting for clustering of children in family child care homes, total HEI-2015 scores were lower at home than in care (ß = -5.18 ± 1.47; 95% CI -8.05 to -2.30; P = 0.003). CONCLUSIONS: Children had healthier dietary intake in family child-care homes vs their respective homes.

Factors Associated with Children's Physical Activity During Youth Soccer Practices.

Purpose: To identify practice and social contextual factors that associate with physical activity (PA) levels of children during their participation in a youth soccer program. Methods: Twenty-seven youth soccer teams serving children ages 6-11 years participated. Research staff directly observed and recorded PA intensity and practice and social contextual factors using momentary time-sampling procedures. Each team was observed for 1 practice, during which approximately 6 children were each observed for twenty 30-s observation blocks (10-s observation, 20-s recording). In total, children were observed for 3,102 intervals. Multilevel logistic regression analyses were conducted to describe associations between PA intensity and practice and social contexts. Interaction terms were introduced into the models to determine if the associations differed across girls-only, boys-only, and coed teams. Results: A total of 158 children were observed across the 27 teams. Children were more likely to engage in moderate or vigorous PA while performing fitness (Odds Ratio [OR], 9.9, 95% CI = 5.34-18.04), game (OR, 4.0, 95% CI = 2.88-5.66), warm-up (OR, 2.8, 95% CI = 1.85-4.11), and drill (OR, 1.9, 95% CI = 1.41-2.67) activities compared to tactic/instructional activities. The associations between PA intensity levels and practice and social contexts did not differ across girls-only, boys-only, and coed teams. Conclusions: Fitness activities and full-team game play were associated with higher PA intensity levels during children's participation in youth soccer practices. Youth sport practice protocols can be modified to increase children's physical activity.

Longitudinal associations between sleep and weight status in infants and toddlers.

BACKGROUND: The limited research assessing relationships between sleep duration and weight status in infants and toddlers relies primarily on parent-reported sleep and cross-sectional studies. OBJECTIVES: Examine whether average sleep duration and changes in sleep duration among 6-24-month-old children were associated with weight-for-length z-scores, and whether these associations varied by race/ethnicity, socioeconomic status and sex. METHODS: Data were collected when children were approximately 6, 12, 18 and 24 months old (N = 116). Sleep duration was measured using actigraphy. Weight-for-length z-scores were calculated using children's height and weight. Physical activity was assessed using accelerometry. Diet was assessed using a feeding frequency questionnaire. Demographic characteristics included sex, race/ethnicity and socioeconomic status. Separate associations of between- and within-person changes in sleep duration were estimated with weight-for-length z-score treated as the outcome variable in linear mixed model analyses. Additional models were assessed that included interactions between sleep and demographic characteristics. RESULTS: At time points where children slept longer at night compared to their own average, their weight-for-length z-score was lower. This relationship was attenuated by physical activity levels. CONCLUSIONS: Increasing sleep duration can improve weight status outcomes in very young children who have low physical activity levels.

A Summary of One Research Team's Contributions to Understanding Physical Activity Behavior in Children and Youth.

Schools are well-positioned to provide physical activity opportunities to help youth achieve the recommended 60 or more daily minutes of moderate-to-vigorous physical activity. The Children's Physical Activity Research Group (CPARG) at the University of South Carolina has focused on understanding physical activity in school-aged youth for 30+ years. The purpose of this article was to critically review (CPARG) contributions to the field in school settings and school-age youth. We reviewed 127 published CPARG articles from six research projects conducted between 1993-2019. The review was guided by questions in five categories: measurement of physical activity and its determinants, characteristics of physical activity behavior, correlates/determinants of physical activity, physical activity interventions, and race/ethnicity and physical activity. Results were summarized by question and synthesized across categories. CPARG contributions included assessing physical activity levels, patterns, forms, and contexts; identifying and measuring physical activity correlates/determinants; and conducting school-based physical activity interventions. Identifying multiple domains of physical activity determinants enables researchers and practitioners to select/design age-appropriate, valid, and reliable instruments to assess determinants. Focusing on determinants enables them to create effective physical activity interventions, environments, programs, and policies in schools. These efforts must address race/ethnicity differences, ensuring that measurement instruments and intervention strategies are culturally appropriate.

The association of physical activity to oral glucose tolerance test outcomes in multiple autoantibody positive children: The TEDDY Study.

OBJECTIVE: To examine the association of physical activity (PA), measured by accelerometry, to hemoglobin AIC (HbA1c) and oral glucose tolerance test (OGTT) outcomes in children who were multiple persistent confirmed autoantibody positive for type 1 diabetes (T1D). METHODS: The Environmental Determinants of Diabetes in the Young (TEDDY) multinational study followed children from birth. Children ≥3 years of age who were multiple persistent confirmed autoantibody positive were monitored by OGTTs every 6 months. TEDDY children's PA was measured by accelerometry beginning at 5 years of age. We examined the relationship between moderate plus vigorous (mod + vig) PA, HbA1c, and OGTT in 209 multiple autoantibody children who had both OGTT and PA measurements. RESULTS: Mod + vig PA was associated with both glucose and C-peptide measures (fasting, 120-min, and AUC); higher mod + vig PA was associated with a better OGTT response primarily in children with longer duration of multiple autoantibody positivity. Mod + vig PA also interacted with child age; lower mod + vig PA was associated with a greater increase in C-peptide response across age. Mod + vig PA was not related to fasting insulin, HOMA-IR or HbA1c. CONCLUSIONS: The OGTT is the gold standard for diabetes diagnosis and is used to monitor those at high risk for T1D. We found higher levels of mod + vig PA were associated with better OGTT outcomes in children ≥5 years of age who have been multiple autoantibody positive for longer periods of time. Physical activity should be the focus of future efforts to better understand the determinants of disease progression in high-risk children.

Behavioral, Environmental, and Demographic Factors Associated with Objectively Measured Physical Activity in Infants.

Background: To describe objectively measured physical activity (PA) in infants, and to identify demographic, behavioral, and environmental factors associated with infants' PA. Methods: Participants were 6-7-month-old infants and their mothers (N = 143 dyads) from two Southeastern US counties. Infant measures included PA assessed by accelerometers at ankle and waist sites, motor developmental status (i.e., stationary and locomotion), and anthropometric characteristics (i.e., height and weight). Mothers provided information on home environment, child care settings, and family demographic factors. PA levels were compared across demographic subgroups. Correlation coefficients described associations between PA and continuous variables, including motor developmental status and anthropometric characteristics. Multiple linear regression analyses examined factors found to be independently associated with PA. Results: Infants' PA counts were greater at the ankle (77,700 counts/hr) vs. the waist site (32,500 counts/hr). In univariate analyses, a diverse set of environmental, behavioral, and infant-level demographic factors were found to be significantly associated with PA at the ankle site. Multivariate analyses indicated that more advanced motor development status (B = 666.3 ± 329.8, p < 0.05), attendance at home child care settings (B = -13,724.4 ± 5083.9, p < 0.05), greater exposure to tummy time (B = 213.5 ± 79.9, p < 0.05), and white racial/ethnic composition (B = -19,953.4 ± 5888.5, p < 0.01) were independently, associated with infants' PA. Conclusions: In 6-7-month-old infants, objectively measured PA was found to be associated with motor developmental status and physical and social environmental factors, including both demographic moderators and factors that are influenced by parents and caregivers. Longitudinal studies are needed to determine if these relationships persist or change as infants develop.

NCS Assessments of the Motor, Sensory, and Physical Health Domains.

As part of the National Children's Study (NCS) comprehensive and longitudinal assessment of the health status of the whole child, scientific teams were convened to recommend assessment measures for the NCS. This manuscript documents the work of three scientific teams who focused on the motor, sensory, or the physical health aspects of this assessment. Each domain team offered a value proposition for the importance of their domain to the health outcomes of the developing infant and child. Constructs within each domain were identified and measures of these constructs proposed. Where available extant assessments were identified. Those constructs that were in need of revised or new assessment instruments were identified and described. Recommendations also were made for the age when the assessments should take place.

The role of parental support for youth physical activity transportation and community-level poverty in the healthy communities study.

This study evaluates whether parental provision of transportation for physical activity is associated with child/adolescent moderate-to-vigorous physical activity, while also evaluating community-level poverty. Self- and parental-reported surveys were administered with parents/caregivers and children in the Healthy Communities Study (N = 5138). Associations between individual-level demographics, community-level poverty, parental provision of transportation for physical activity, and moderate-to-vigorous physical activity were examined in multi-level models. Even when accounting for community-level poverty, which was significantly associated with lower moderate-to-vigorous physical activity, parental provision of transportation for physical activity was positively associated with greater moderate-to-vigorous physical activity. This study provides evidence for the importance of considering multiple systems of influence (e.g., community and individual factors) and considering how gaps in physical activity transportation for youth can be addressed in future health policies.

An observation system to assess physical activity of children with developmental disabilities and delays in preschool.

BACKGROUND: Physical activity (PA) behaviors during preschool settings can influence the health and development of children with developmental disabilities (DD). There is a need for a direct observation system that simultaneously assesses PA and preschool environmental contexts. OBJECTIVE: The purpose of this study was to develop an observation instrument for measuring PA and related contextual factors of preschoolers with DD, and to establish content validity and reliability. METHODS: Content validity was established through consultation with experts, informal observations in inclusive and special education preschools, and literature reviews. Categories and codes were identified and modified from existing observational systems for young children. Reliability was assessed in a convenience sample of preschool children with DD using a cross-sectional design. Data were collected using a momentary time sampling system (5-sec observe, 25-sec record) following a focal child. Inter-rater reliability was assessed during 20% of the observation sessions. RESULTS: The instrument development process resulted in ten coding categories that accounted for PA levels, types, and social and physical environmental contexts relevant to preschoolers with disabilities. Observers completed 137.5 observation sessions, yielding 5498 30-s observation intervals. Interval-by-interval percent agreement was excellent (91%-100%) and kappa values were high (0.82-0.99). CONCLUSIONS: The instrument was found to be a reliable measure of PA of preschoolers with DD and provided important contextual information about PA behaviors in early childhood special education settings. Additionally, it allowed for the simultaneous measurement of specific types and contexts of PA behaviors of preschoolers with DD and will be useful for describing PA and informing future interventions.

Preschool Environmental Influences on Physical Activity in Children with Disabilities.

PURPOSE: The purpose of this study was to describe associations between physical and social environmental features of preschools and physical activity behaviors of young children with developmental disabilities. METHODS: A sample of 34 preschool-age children (mean age, 4.28 ± 1.07; male, 64.7%) with developmental disabilities participated in this study. Physical activity and preschool environmental factors were measured through direct observation using the Observational System for Recording Physical Activity in Children-Developmental Disabilities version. Children were observed approximately eight times over the course of a week, yielding a total of 11, 310 observation intervals. The number of intervals and percentage of time spent in physical activity across environmental contexts were calculated. Logistic regression analyses were conducted to determine associations between time spent in physical activity and features of the physical and social environment. RESULTS: Children with disabilities were sedentary for most of the observed intervals (81.5%). Children were 4.8 times (confidence interval (CI), 4.25-5.50) more likely to be physically active while outdoors compared with indoors. Physical activity was more likely to occur in open spaces (odds ratio [OR], 3.3; CI, 2.59-4.19) and when using portable play equipment (OR, 2.7; CI, 1.31-5.64) compared with fixed playground equipment. While indoors, children in this study were 5.6 times (CI, 3.78-8.03) more likely to be active when in therapy compared with group time activities. Physical activity was more likely to occur when in solitary (OR, 3.4; CI, 2.87-4.10) or one-on-one group contexts (OR, 1.7-2.9) compared with in groups with an adult present. CONCLUSIONS: Certain features of the preschool setting, such as location and social group composition, were more conducive to physical activity than others. Children with disabilities would benefit from more time outdoors and in smaller group settings during preschool.

Cross-Country Comparisons of Physical Activity and Sedentary Behavior among 5-Year-Old Children.

PURPOSE: Previous studies have observed that physical activity (PA) levels tend to be lower in the U.S. population than in many other countries. Within the U.S., PA levels in children are lower in the South than in other regions. Cross-country and interregional differences in PA have not been studied in young children. METHODS: In an ongoing study of children at genetic risk for Type 1 diabetes, PA was measured by accelerometry in samples of 5-year-old children (n = 2008) from Finland (n = 370), Germany (n = 85), Sweden (n = 706), and the U.S. (n = 847). The U.S. sample was drawn from centers in Washington State, Colorado, and Georgia/Florida. Children wore accelerometers for 7 days, and the data were reduced to daily minutes of light-, moderate- (MPA), vigorous- (VPA), and moderate-to-vigorous- (MVPA) intensity PA and sedentary behavior. Multiple regression was used to compare children across countries and across regions in the U.S, adjusting for wear time, body mass index, and demographic characteristics. RESULTS: After adjusting for previously mentioned factors, MVPA and MPA were lower in U.S. children than those in Finland and Sweden. Estimates of physical activity were higher in Finland than in other countries, although not all comparisons were significantly different. U.S children spent significantly more time in sedentary behavior than children in Finland (p < 0.0001). Within the U.S., children's PA was consistently lowest in Georgia/Florida and highest in Washington. CONCLUSIONS: Cross-country differences in PA, previously reported for adults and adolescents, are evident in 5-year-old children. In general, PA levels are lower in U.S. children than their European counterparts, and within the U.S., are lower in Georgia/Florida and Colorado than in Washington. Future studies should be designed to identify the factors that explain these differences.

Longitudinal Associations Between Psychosocial, Home, and Neighborhood Factors and Children's Physical Activity.

BACKGROUND: Physical activity (PA) provides important health benefits to children, and a large percentage of children's PA occurs at home. The purpose of this study was to examine the associations between psychosocial, home, and neighborhood environmental factors and children's reported PA at home and in the neighborhood, during the transition from elementary to high school. METHODS: A total of 555 participants (44% boys) were recruited in grade 5 and followed through grades 6, 7, and 9. Children self-reported PA in 3 locations-at home, in the neighborhood, and on the street. Children reported parent support and neighborhood environment, parents reported PA equipment, and a windshield survey assessed incivilities and outside PA equipment. Longitudinal Poisson models evaluated the relationships between environmental variables and 3 self-reported PA variables, adjusting for gender, race/ethnicity, and parent education. RESULTS: Parent support and PA equipment were significant positive predictors of home PA. Child's perceived environment (positive) and incivilities (negative) were significant predictors of neighborhood PA. Parental support, perceived environment, and outside PA equipment were positive significant predictors of street PA. CONCLUSIONS: This study supports the need for both family and community/neighborhood PA interventions that encourage parents to support child PA and for communities to reduce incivilities.

Sport participation, physical activity and sedentary behavior in the transition from middle school to high school.

OBJECTIVES: To examine associations between sport participation, and objectively assessed physical activity and sedentary behavior in youth during the transition from middle school to high school. DESIGN: Longitudinal study with 2-year follow-up. METHODS: Sport participation and accelerometer-measured physical activity and sedentary behavior were assessed in 306 children (122 males, 184 females) when they were in 7th and 9th grades (mean age of 12.5 ±â€¯0.5 years). RESULTS: Sport participation and physical activity declined from 7th to 9th grade, but total physical activity (d = 0.38, p < 0.0001) and moderate-to-vigorous physical activity (d = 0.26, p = 0.0004) remained higher in sport participants compared to non-participants. In 9th grade, the full sample of sport participants compared to non-participants had higher levels of total physical activity (20.7 min/h vs. 18.5 min/h) and moderate-to-vigorous physical activity (1.8 min/h vs. 1.6 min/h). Sex-specific analysis revealed similar patterns in both females and males. Sedentary behavior remained lower (d = -0.37, p = <0.0001) in the full sample of sport participants compared to non-participants (39.8 min/h vs. 41.7 min/h) in 9th grade. Similar patterns were observed in both females and males. CONCLUSIONS: Children's participation in sport is associated with greater levels of physical activity and lower levels of sedentary behavior during the transition from middle school to high school. Promoting children's participation in sports could be an effective public health strategy to help children meet the current physical activity guideline.

Comparison of Indirect Calorimetry- and Accelerometry-Based Energy Expenditure During Children's Discrete Skill Performance.

Purpose: To compare children's energy expenditure (EE) levels during object projection skill performance (OPSP; e.g., kicking, throwing, striking) as assessed by hip- and wrist-worn accelerometers. Method: Forty-two children (female n = 20, Mage = 8.1 ± 0.8 years) performed three, nine-minute sessions of kicking, over-arm throwing, and striking at performance intervals of 6, 12, and 30 seconds. EE was estimated using indirect calorimetry (COSMED k4b2) and accelerometers (ActiGraph GT3X+) worn on three different locations (hip, dominant-wrist, and non-dominant-wrist) using four commonly used cut-points. Bland-Altman plots were used to analyze the agreement in EE estimations between accelerometry and indirect calorimetry (METS). Chi-square goodness of fit tests were used to examine the agreement between accelerometry and indirect calorimetry. Results: Hip- and wrist-worn accelerometers underestimated EE, compared to indirect calorimetry, during all performance conditions. Skill practice at a rate of two trials per minute resulted in the equivalent of moderate PA and five trials per minute resulted in vigorous PA (as measured by indirect calorimetry), yet was only categorized as light and/or moderate activity by all measured forms of accelerometry. Conclusion: This is one of the first studies to evaluate the ability of hip- and wrist-worn accelerometers to predict PA intensity levels during OPSP in children. These data may significantly impact PA intervention measurement strategies by revealing the lack of validity in accelerometers to accurately predict PA levels during OPSP in children.

Self-efficacy, beliefs, and goals: Moderation of declining physical activity during adolescence.

OBJECTIVE: To examine whether the decline in physical activity observed from childhood through adolescence is explained by moderating effects of self-efficacy on concurrent changes in children's goals and beliefs about their physical activity environments. METHOD: Latent growth modeling was used in longitudinal tests in a cohort of 79 boys and 108 girls assessed in 5th, 6th, 7th, 9th, and 11th grades. RESULTS: Physical activity measured objectively by an accelerometer declined most in students who had bigger declines in self-efficacy and (1) maintained higher perceptions of barriers to physical activity, (2) had bigger declines in enjoyment and fitness goals, or (3) had smaller declines in appearance and social goals. CONCLUSIONS: Trials of physical activity interventions based on social-cognitive theory should consider that the influence of changing goals on physical activity may differ according to whether students maintain high efficacy beliefs about overcoming barriers to physical activity coincident with perceptions of their physical activity environment. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

Moderating effect of the neighbourhood physical activity environment on the relation between psychosocial factors and physical activity in children: a longitudinal study.

BACKGROUND: Few studies have examined the moderating role of neighbourhood environments on the relation between psychosocial factors and physical activity, and results of these studies are mixed. This study examined this relationship in 636 fifth to seventh graders from South Carolina, USA. METHODS: From 2010 to 2013, children and their parent/guardian completed annual self-reported surveys assessing psychosocial factors, and children wore accelerometers for 1 week each year. Neighbourhood environments were classified as supportive or non-supportive for physical activity (PA) based on in-person audits of facilities near children's homes and windshield surveys of children's streets. Growth curve analyses were completed to assess the moderating effect of the neighbourhood physical activity environment (NPAE) on the relation between psychosocial factors and total physical activity (TPA) over time. RESULTS: Significant interactions on TPA were found for (1) time, NPAE and parent-reported parent support for PA; (2) time, NPAE and child-reported equipment in the home; (3) child-reported parental support for PA and time; (4) child-reported parental support for PA and NPAE; (5) PA self-schema and time and (6) child-reported parental encouragement and time. Parental support and a supportive NPAE were important for TPA, especially as children transitioned to middle school, whereas home equipment and a supportive NPAE were important for fifth graders' TPA. CONCLUSION: Consistent with the socioecological model, PA behaviour was dependent on interacting effects across levels of influence. Generally, both a supportive NPAE and positive psychosocial factors were needed to support TPA. Factors influencing PA across multiple levels should be addressed in PA interventions.

Children's metabolic expenditure during object projection skill performance: New insight for activity intensity relativity.

Objective: To examine children's energy expenditure (EE) during object projection skill performance at three intensity intervals. Methods: Children's (42, Mage = 8.1) average metabolic equivalents of task (METs) were calculated using a COSMED K4b2 while they repeatedly performed blocks of kicking, throwing (overhand), and striking (two-handed) during 6, 12, and 30-s interval conditions. A repeated-measures analysis of covariance examined differences in METs while controlling for skill level. Results: Data indicated a main effect for interval condition (df = 2, 123, F = 94.36, p <.001, η2 = .605). Post hoc t-tests demonstrated decreasing performance interval times yielded progressively higher METs (p <.001) across the three conditions (30s = 4.5±0.8 METs, 12s = 6.3±1.3, 6s = 8.3±1.6). There also was a main effect for sex (df = 1,120, F = 52.28, p <.001 η2 = .305). Boys demonstrated higher METs at each performance interval (p <.001). Conclusion: Skill practice with a maximum of one trial every 30s resulted in the equivalent of at least moderate physical activity (>4.0 METs) and intervals of 6s demonstrated vigorous physical activity (>7.0 METs). Practicing/performing object projection skills, even at intervals that allow for adequate instruction and feedback (i.e., 1 trial/30s), promotes MVPA in children.

Group-based physical activity trajectories in children transitioning from elementary to high school.

BACKGROUND: Physical activity has been observed repeatedly to decline as children transition into adolescence; however, few studies have explored the possibility that sub-groups of children experience unique patterns of change during this transition. The purpose of this longitudinal study was to examine the physical activity trajectories in clusters of youth transitioning from 5th to 11th grade. METHODS: Participants (n = 652) were recruited as 5th graders (ages 10-12 years) from elementary schools (n = 21) in two school districts. Demographic, anthropometric, and physical activity data were collected once per year when children were in 5th, 6th, 7th, 9th, and 11th grades. Children wore accelerometers for 7 consecutive days. Group-based trajectory modeling statistical techniques were applied to identify patterns of physical activity trajectories. Posterior probabilities confirmed participants' membership in their respective group. RESULTS: Three distinct physical activity trajectories were identified. Group 1 (n = 27) remained highly active over time, and physical activity increased from ages 14 to 16 years. Group 2 (n = 365) was active at baseline, but activity declined and remained low as group members aged. Group 3 (n = 260) had the lowest levels of physical activity at all ages, and activity declined from ages 10 to 16 years. CONCLUSIONS: While most children experienced a decline in physical activity as they transitioned into high school, some remained highly active and increased their level of physical activity. Future studies should test physical activity interventions for youth that are tailored for age-related trajectory groups.

Change in Children's Physical Activity: Predictors in the Transition From Elementary to Middle School.

INTRODUCTION: Interventions to promote physical activity in children should be informed by knowledge of the factors that influence physical activity behavior during critical developmental transitions. The purpose of this study is to identify, from a comprehensive, multidomain set of factors, those that are associated with change in objectively measured physical activity in children as they transition from elementary to middle school. METHODS: The study used a prospective cohort design, with children observed in fifth, sixth, and seventh grades. Growth curve analyses were used to examine associations between exposure variables measured at baseline and children's physical activity across three observations. A total of 828 children, aged 10.6 (SD=0.5) years at baseline provided physical activity data in fifth grade and at one or both follow-ups. Exposure variables assessed child characteristics, parent characteristics, home characteristics, social factors, school environment, and community characteristics. Physical activity was measured via accelerometry. Data were collected in two school districts in South Carolina in 2010-2013 and analyzed in 2017. RESULTS: Variables measured within the child, parent/home, and community domains were positively associated with children's physical activity as they transitioned from fifth to seventh grade. These included parent encouragement of physical activity, parental support for physical activity, child sports participation, parent's report of the child's physical activity level, the child's time spent outdoors, social spaces for physical activity in the community, and the number of physical activity facilities that were proximal to the child's home. CONCLUSIONS: Interventions designed to increase children's physical activity should include strategies that target multiple domains of influence.