Association of physical activity, sedentary behavior, diet quality with adiposity: a longitudinal analysis in children categorized by baseline weight status.

BACKGROUND/OBJECTIVES: Childhood obesity rates have increased in recent years. The effectiveness of future public health interventions to reduce childhood obesity will be enhanced by a better understanding of behavioral factors that influence adiposity in children as they transition from childhood to adolescence. The purpose of this study was to examine whether initial weight status modifies the longitudinal associations of physical activity, sedentary behavior, and diet quality with changes in adiposity over time. SUBJECTS/METHODS: A total of 658 children (45% boys) were stratified into 3 groups based on 5th grade BMI percentiles ( < 85th, 85-95th, > 95th) and followed from 5th grade to 6th and/or 7th grade. Study variables, including fat-mass-index (FMI), moderate-to-vigorous physical activity (MVPA), diet quality, and sedentary behavior, were measured at 5th, 6th, and/or 7th grades. Separate growth curve models were conducted within each weight status group to examine the associations between MVPA, sedentary behavior, diet quality and adiposity, operationalized as FMI. All models controlled for sex, maturity offset, race, and parent education. RESULTS: Of the 658 children, 53% were classified with normal weight at baseline, 18% with overweight, and 29% with obesity. Associations between MVPA, sedentary behavior, diet quality and FMI varied within each weight status group. MVPA was negatively associated with adiposity (FMI) for all weight status groups. Diet quality and sedentary behavior were associated with adiposity only in children with obesity at baseline; neither diet quality nor sedentary behavior was associated with FMI for those with overweight. CONCLUSIONS: MVPA was negatively associated with adiposity (FMI) in all weight status groups, suggesting that MVPA may protect against higher adiposity. Sedentary behavior and diet quality were associated with adiposity only in children with obesity at baseline; neither sedentary behavior nor diet quality was associated with FMI for children with overweight.

Longitudinal association of biological maturation with physical activity behaviors in girls transitioning from 5th to 7th grade.

INTRODUCTION: This longitudinal study determined if social cognitive variables influence physical activity in girls stratified on the basis of maturity status. METHODS: Participants attended South Carolina public schools (Mage in 5th grade = 11.1 years) and included a cohort of 529 girls who provided physical activity data in the 5th grade and in 6th and/or 7th grade. The measure of maturity status was age at peak height velocity (APHV) estimated from maturity offset when the children were in the 5th grade. The Earlier Maturity (EM) group included girls whose APHV was one standard deviation or more below the mean APHV for the full sample. All other girls were placed in the Later Maturity (LM) group. Physical activity was assessed at each time point via accelerometry. Social-cognitive variables were assessed at each time point by a questionnaire measuring self-efficacy, enjoyment, competence, appearance, fitness, and social motives for physical activity. Growth curves for the total, Earlier Maturing, and Later Maturing groups assessed relationships between physical activity over time and time-varying social cognitive variables. RESULTS: Physical activity was lower in the Earlier Maturing group and was positively associated with self-efficacy and enjoyment motivation in the total group. These relationships were observed in the 5th grade and maintained through 7th grade. In the Later Maturing group, we observed positive relationships between physical activity and self-efficacy, enjoyment and competence motivation. CONCLUSIONS: Strategies to increase confidence, skills, and enjoyment of physical activity may only be effective for promoting activity among later maturing girls.

The Effect of Light-Intensity Cycling on Mood and Working Memory in Response to a Randomized, Placebo-Controlled Design.

OBJECTIVE: Prior attempts to measure psychological responses to exercise are potentially limited by a failure to account for participants' expectations, the absence of a valid exercise placebo, and demand characteristics. The purpose of this study was to explore the main and interactive effects of a manipulation designed to increase expectations about the psychological benefits of an acute bout of active, light-intensity (treatment), and passive (placebo) cycling on mood and cognition. Demand characteristics were attenuated during recruitment, informed consent, and interactions with test administrators by communicating to participants that the study purpose was to assess the effects of active and passive cycling on respiration, heart rate, and muscle activation. METHODS: A repeated-measures, randomized, placebo-controlled design (n = 60) was used with cycling (active, passive) and information (informed, not informed) as between-subjects factors. State anxiety, feelings of energy, and working memory (percent accuracy and reaction time for correct responses) were measured at baseline (time 1), immediately after cycling (time 2) and 20 minutes after cycling (time 3). RESULTS: Most participants did not guess the purpose of the study (~92%) or expect a reduction in state anxiety (85%) or an increase in energy (80%) or cognitive performance (~93%). Mood and cognitive performance were not improved by active or passive cycling (all p values ≥ .12). CONCLUSIONS: The methods used here to disguise the experimental hypotheses provide a potential framework for reducing demand characteristics and placebo responses in future investigations of psychological responses to exercise.

Perceptions of the Neighborhood Environment and Children's Afterschool Moderate-to-Vigorous Physical Activity.

Previous research suggests the neighborhood environment may be an important influence on children's physical activity (PA) behaviors; however, findings are inconsistent. The purpose of this study was to further understand the relationship between perceptions of the neighborhood environment and children's afterschool moderate-to-vigorous PA. Utilizing a structural equation modeling technique, we tested a conceptual model linking parent and child perceptions of the neighborhood environment, parent support for PA, and child outdoor PA with children's afterschool moderate-to vigorous PA. We found that child perception of the neighborhood environment and outdoor PA were positively associated with afterschool moderate-to-vigorous PA. In addition, parent support for PA positively influenced children's outdoor PA. The neighborhood environment and outdoor activity appear to play an influential role on children's afterschool PA behaviors.

Self-regulation of exercise behavior in the TIGER study.

OBJECTIVE: This study aimed to test experiential and behavioral processes of change as mediators of the prediction of exercise behavior by two self-regulation traits, self-efficacy and self-motivation, while controlling for exercise enjoyment. METHODS: Structural equation modeling was applied to questionnaire responses obtained from a diverse sample of participants. Objective measures defined adherence (928 of 1,279 participants attended 80 % or more of sessions) and compliance (867 of 1,145 participants exercised 30 min or more each session at their prescribed heart rate). RESULTS: Prediction of attendance by self-efficacy (inversely) and self-motivation was direct and also indirect, mediated through positive relations with the typical use of behavioral change processes. Enjoyment and self-efficacy (inversely) predicted compliance with the exercise prescription. CONCLUSIONS: The results support the usefulness of self-regulatory behavioral processes of the transtheoretical model for predicting exercise adherence, but not compliance, extending the supportive evidence for self-regulation beyond self-reports of physical activity used in prior observational studies.

A Comprehensive Planning Framework for Designing Effective Physical Activity Interventions in Youth.

BACKGROUND: Effective physical activity (PA) interventions are needed to counter the insufficient and declining levels of PA in youth. These require an updated, comprehensive planning framework that consolidates recent decades of progress in promoting PA in young children, children, and adolescents. Effective PA interventions require program planning and conceptual model development that target a coordinated and multilevel set of age-specific PA determinants. Accordingly, this paper presents a comprehensive planning framework that researchers can use to design intervention research to promote PA in youth. METHODS: The first author conducted targeted searches through Google Scholar to compile PA models/frameworks/guides applicable to youth, a comprehensive set of PA determinants, and determinant-linked strategies to promote PA focusing on review articles. The information was summarized in tables, synthesized, and used to create a planning framework, all of which were reviewed by coauthors. RESULTS: The APPLE Framework for Planning PA Opportunities for Youth (APPLE = Age, PA focus, Place and time, Leverage relevant influences and strategies, and ensure Enjoyable PA opportunities) incorporated all core elements from targeted reviews to create a comprehensive planning framework. The APPLE Planning Framework has a set of questions/prompts that guide the intervention planning process and conceptual model templates to organize planning efforts for designing intervention research. CONCLUSIONS: The APPLE Framework for Planning PA Opportunities for Youth will enable researchers to develop comprehensive conceptual models to guide the design of PA interventions for youth. Future research should refine the model and its components to enable PA intervention research in youth to move forward.

Determinants of Change in Physical Activity in Children during the Transition from Elementary to High School.

INTRODUCTION: Effective public health interventions targeting factors that influence physical activity are urgently needed to reduce the age-related decline in physical activity in youth. The purpose of this study was to identify associations between physical activity and a set of potential influences on physical activity in children as they transition from elementary to high school. METHODS: Participants were 951 children from South Carolina school districts who completed outcome and independent variable measures on at least two time points from the 5th to 11th grades in 2010-2017. The primary outcome variable was physical activity, measured by accelerometry. Independent variables included a comprehensive set of variables in the child, parent/home, school, and community domains. Children, parents and school administrators, and staff completed questionnaires to assess psychosocial and home, school, and neighborhood environmental influences. Growth curve analyses identified independent variables associated with physical activity over time, either as a main effect or as an interaction with age. RESULTS: As main effects, self-efficacy, self-schema, sport participation, weekday outdoor hours, importance of child participating in sports and physical activity, safe to play outside, and Physical Activity Resource Assessment weighted score were positively associated with physical activity. The associations between physical activity and enjoyment motivation, appearance motivation, weekend outdoor time, and home equipment exhibited significant interactions with age. Enjoyment motivation influenced physical activity during the earlier years, whereas the remaining three variables influenced physical activity in the later years. CONCLUSIONS: Interventions should target multiple domains of influences that may vary by age.

Construct validity of selected measures of physical activity beliefs and motives in fifth and sixth grade boys and girls.

OBJECTIVE: Scales used to measure selected social-cognitive beliefs and motives for physical activity were tested among boys and girls. METHODS: Covariance modeling was applied to responses obtained from large multi-ethnic samples of students in the fifth and sixth grades. RESULTS: Theoretically and statistically sound models were developed, supporting the factorial validity of the scales in all groups. Multi-group longitudinal invariance was confirmed between boys and girls, overweight and normal weight students, and non-Hispanic black and white children. The construct validity of the scales was supported by hypothesized convergent and discriminant relationships within a measurement model that included correlations with physical activity (MET • min/day) measured by an accelerometer. CONCLUSIONS: Scores from the scales provide valid assessments of selected beliefs and motives that are putative mediators of change in physical activity among boys and girls, as they begin the understudied transition from the fifth grade into middle school, when physical activity naturally declines.

Transtheoretical Model Constructs for Physical Activity Behavior are Invariant across Time among Ethnically Diverse Adults in Hawaii.

OBJECTIVES: Physical activity (PA) research applying the Transtheoretical Model (TTM) to examine group differences and/or change over time requires preliminary evidence of factorial validity and invariance. The current study examined the factorial validity and longitudinal invariance of TTM constructs recently revised for PA. METHOD: Participants from an ethnically diverse sample in Hawaii (N=700) completed questionnaires capturing each TTM construct. RESULTS: Factorial validity was confirmed for each construct using confirmatory factor analysis with full-information maximum likelihood. Longitudinal invariance was evidenced across a shorter (3-month) and longer (6-month) time period via nested model comparisons. CONCLUSIONS: The questionnaires for each validated TTM construct are provided, and can now be generalized across similar subgroups and time points. Further validation of the provided measures is suggested in additional populations and across extended time points.

Evidence for the construct validity of self-motivation as a correlate of exercise adherence in French older adults.

OBJECTIVES: Exercise adherence involves a number of sociocognitive factors that influence the adoption and maintenance of regular physical activity. Among trait-like factors, self-motivation is believed to be a unique predictor of persistence during behavior change. The aim of this study was to validate the factor structure of a French version of the Self-Motivation Inventory (SMI) and to provide initial convergent and discriminant evidence for its construct validity as a correlate of exercise adherence. METHOD: Four hundred seventy-one elderly were recruited and administered the SMI-10. Structural equation modeling tested the relation of SMI-10 scores with exercise adherence in a correlated network that included decisional balance and perceived quality of life. RESULTS: Acceptable evidence was found to support the factor validity and measurement equivalence of the French version of the SMI-10. Moreover, self-motivation was related to exercise adherence independently of decisional balance and perceived quality of life, providing initial evidence for construct validity.

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.

Validity of processes of change in physical activity among college students in the TIGER study.

OBJECTIVE: To test the factorial validity and measurement equivalence/invariance of scales used to measure processes of change derived from the Transtheoretical Model (TTM) applied to physical activity. METHODS: Confirmatory factor analysis of questionnaire responses obtained from a diverse sample (N = 1,429) of students enrolled in the Training Interventions and Genetics of Exercise Response (TIGER) Study at the University of Houston during academic years 2004-2005 through 2007-2008. Cohorts of students (N = 1,163) completed the scales at the beginning and end of each Fall semester, permitting longitudinal analysis. RESULTS: Theoretically and statistically sound models were developed that support the factorial validity of nine of the ten hypothesized 1st-order factors. A structure of nine correlated 1st order factors or a hierarchical structure of those factors subordinate to two correlated 2nd-order factors were each defensible. Multi-group invariance of each model was confirmed across race/ethnicity groups (African American, Hispanic, non-Hispanic White), gender, age, BMI levels, employment status, physical activity level, and study adherence. Longitudinal invariance across the semester was also confirmed. CONCLUSION: The scores from the scales provide valid assessments that can be used in observational studies of naturally occurring change or in interventions designed to test the usefulness of TTM processes as mediators of change in physical activity among college students. Item content and factor structure require further evaluation in other samples in order to advance TTM theory applied to physical activity.

Using constructs of the transtheoretical model to predict classes of change in regular physical activity: a multi-ethnic longitudinal cohort study.

Explaining variation in meeting recommended levels of physical activity across time is important for the design of effective public health interventions. To model longitudinal change in constructs of the Transtheoretical Model and test their hypothesized relations with change in meeting the Healthy People 2010 guidelines for regular participation in moderate or vigorous physical activity, a cohort (N = 497) from a random, multi-ethnic sample of 700 adults living in Hawaii was assessed at 6-month intervals three or more times for 2 years. Latent class growth modeling was used to classify people according to their initial levels and trajectories of change in the transtheoretical variables and separately according to whether they met the physical activity guideline each time. Relations of the variables and their change with classes of meeting the guideline were then tested using multinomial logistic regression. Despite declines or no change in mean scores for all transtheoretical variables except self-efficacy, participants who maintained or attained the physical activity guideline were more likely to retain higher scores across the 2 years of observation. The usefulness of transtheoretical constructs for predicting maintenance of, or increases in, public health levels of physical activity was generally supported. These longitudinal results support earlier cross-sectional findings which indicate that, contrary to theory, people appear to use both experiential and behavioral processes while they attempt to increase or maintain their physical activity.

Associations of quality of life with physical activity, fruit and vegetable consumption, and physical inactivity in a free living, multiethnic population in Hawaii: a longitudinal study.

INTRODUCTION: High intake of fruit and vegetables and being physically active are associated with reduced risk of chronic diseases. In the current study, we examined the associations of physical activity, fruit and vegetable consumption, and TV/video watching (indicator for physical inactivity) with perceived quality of life (QOL) in a sample of free living adults. METHODS: A cohort (N = 139) from a random, multi-ethnic sample of 700 adults living in Hawaii was evaluated at 3-month intervals for the first year and 6-month intervals for the second year. QOL was assessed from self-reports of mental or physical health at the end of the study. RESULTS: Overall, the cohort participants appeared to maintain relatively constant levels of physical activity, fruit and vegetable intake, and TV/video watching. Physical activity was positively related to mental health (p-values < 0.05), but not physical health, at all time points regardless of participants' fruit and vegetable consumption and hours of TV/video watching. Neither mental nor physical health was associated with fruit and vegetable intake or TV/video watching. CONCLUSION: Our study supports that physical activity is positively associated with mental health. Fruit and vegetable consumption and TV/video watching may be too specific to represent an individual's overall nutritional status and physical inactivity, respectively.

Validity of social-cognitive measures for physical activity in middle-school girls.

OBJECTIVE: The factorial validity and measurement equivalence/invariance of scales used to measure social-cognitive correlates of physical activity among adolescent girls were examined. METHODS: Confirmatory factor analysis was applied to questionnaire responses obtained from a multi-ethnic sample (N = 4885) of middle-school girls from six regions of the United States. A cohort of 1893 girls completed the scales in both sixth and eighth grades, allowing longitudinal analysis. RESULTS: Theoretically and statistically sound models were developed for each scale, supporting the factorial validity of the scales in all groups. Multi-group and longitudinal invariance was confirmed across race/ethnicity groups, age within grade, BMI categories, and the 2-year period between grades. CONCLUSIONS: The scores from the scales provide valid assessments of social-cognitive variables that are putative mediators or moderators of change in physical activity. The revised scales can be used in observational studies of change or interventions designed to increase physical activity among girls during early adolescence.

Social-cognitive correlates of physical activity in a multi-ethnic cohort of middle-school girls: two-year prospective study.

OBJECTIVE: The study examined social-cognitive correlates of physical activity in a multi-ethnic cohort of girls from six regions of the United States who participated in the Trial of Activity for Adolescent Girls during their 6th and 8th grade school years. METHODS: Girls completed validated questionnaires and wore accelerometers that measured weekly physical activity in the spring of 2002 and 2005. RESULTS: In 8th grade, self-efficacy and perceived social support had indirect relations with physical activity mediated through perceived barriers, which was inversely related to physical activity. Self-efficacy also had a direct relation with physical activity. CONCLUSIONS: Correlations were smaller than those obtained in studies that measured physical activity by self-reports, suggesting that previous estimates were inflated by common method artifact. Nonetheless, physical activity trials among girls during early adolescence might focus on increasing self-efficacy for overcoming barriers to physical activity and on ways by which perceived barriers can otherwise be reduced.

Investigating fruit and vegetable consumption using the transtheoretical model.

PURPOSE: Test the applicability of the transtheoretical model (TTM) to adult fruit/vegetable consumption. DESIGN: Cross-sectional random-digit dial survey. SETTING: Hawaii. SUBJECTS: 700 (62.6% female; age [mean +/- SD], 47 +/- 17.1 years; education [mean +/- SD], 14.6 +/- 2.8 years; 35.0% white, 31.1% Asian, 22.1% native Hawaiian/Pacific Islander, 11.8% other). MEASURES: Stages, processes, self-efficacy, decisional balance, and self-reported fruit/vegetable consumption. ANALYSIS: Confirmatory factor analysis tested the factor structure. Analyses of variance were used to explore stage differences in constructs. RESULTS: Stage distribution was precontemplation (33%), contemplation (4%), preparation (37%), action (3%), and maintenance (23%). A 10-factor process model with two higher-order correlated factors (experiential and behavioral) provided the best data fit (chi2 = 1446.12; df = 366; p < .0001; comparative fit index [CFI] = .89; standardized root mean square residual [SRMR] = .05). The self-efficacy structure fit the data well (chi 2 = 81.86; df = 9; p < .0001; CFI = .94; SRMR = .04), as did the decisional balance structure (chi2 = 37.42; df = 19; p = .007; CFI = .99; SRMR = .02). Processes, self-efficacy, decisional balance, and fruit/vegetable consumption behavior differed significantly by stage, with medium effect sizes for most variables. CONCLUSION: The variables revealed adequate fit to the theorized measurement models. TTM predictions regarding stage differences in self-efficacy, pros and cons, and fruit/vegetable consumption were confirmed; however, most experiential and behavioral processes increased in the early stages and then leveled off.

Dose relations between goal setting, theory-based correlates of goal setting and increases in physical activity during a workplace trial.

The effectiveness of an intervention depends on its dose and on moderators of dose, which usually are not studied. The purpose of the study is to determine whether goal setting and theory-based moderators of goal setting had dose relations with increases in goal-related physical activity during a successful workplace intervention. A group-randomized 12-week intervention that included personal goal setting was implemented in fall 2005, with a multiracial/ethnic sample of employees at 16 geographically diverse worksites. Here, we examined dose-related variables in the cohort of participants (N = 664) from the 8 worksites randomized to the intervention. Participants in the intervention exceeded 9000 daily pedometer steps and 300 weekly minutes of moderate-to-vigorous physical activity (MVPA) during the last 6 weeks of the study, which approximated or exceeded current public health guidelines. Linear growth modeling indicated that participants who set higher goals and sustained higher levels of self-efficacy, commitment and intention about attaining their goals had greater increases in pedometer steps and MVPA. The relation between change in participants' satisfaction with current physical activity and increases in physical activity was mediated by increases in self-set goals. The results show a dose relation of increased physical activity with changes in goal setting, satisfaction, self-efficacy, commitment and intention, consistent with goal-setting theory.

Do intervention fidelity and dose influence outcomes? Results from the move to improve worksite physical activity program.

The purpose of this paper is to evaluate the implementation of the Move to Improve worksite physical activity program using a four step framework that includes the following: (i) defining the active ingredients, (ii) using good methods to measure implementation, (iii) monitoring implementation and (iv) relating implementation to outcomes. The intervention active ingredients consisted of a goal setting behavior change program, a team competition and environmental supports. Intervention fidelity and dose were measured by surveys administered to site co-ordinators, team captains and employees. Implementation was monitored by the use of biweekly assessments that tracked individual physical activity levels and through weekly reports of the project director and site co-ordinators. Latent growth modeling was conducted to determine whether intervention outcomes were affected by site implementation (i.e. fidelity) and/or participation by employees (i.e. dose). Results showed high levels of intervention fidelity, moderate to high levels of intervention dose delivered and moderate levels of the intervention dose received. Level of implementation affected the degree of change in vigorous physical activity (Mean = 5.4 versus 2.2; chi(2) = 4.9, df = 1), otherwise outcome measures were unaffected by fidelity and dose. These findings suggest that practitioners should focus more energy assuring that the core components are fully implemented and be less concerned about the level of participation.

Personal, Social, and Environmental Influences on Physical Activity in Groups of Children As Defined by Different Physical Activity Patterns.

BACKGROUND: Interventions promoting physical activity (PA) in youth have had limited success, in part because studies with methodological challenges have yielded an incomplete understanding of personal, social, and environmental influences on PA. This study described changes in these factors for subgroups of youth with initially high PA that decreased (Active-Decline) compared with children with initially low PA that decreased (Inactive-Decline) from fifth to ninth grades. METHODS: Observational, prospective cohort design. Participants (n = 625) were fifth-grade children recruited in 2 school districts and followed from elementary to high school. Students and their parents responded to questionnaires to assess personal, social, and perceived physical environmental factors in the fifth (mean age = 10.5 [.5] y) and ninth (mean age = 14.7 [.6] y) grades. Analyses included a mixed-model 2-way repeated analysis of variances. RESULTS: Children in the Active-Decline compared with those in the Inactive-Decline group showed a more favorable profile in 6 of 8 personal variables (perceived barriers, self-efficacy, self-schema, enjoyment, competence, and fitness motives) and 4 of 6 social variables (friend support, parent encouragement, parent support, and parent-reported support). CONCLUSIONS: The results suggest efforts to promote PA should target selected personal, social, and perceived environmental factors beginning before age 10 and continuing through adolescence.