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.

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.

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.

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.

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.

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.

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.

Acute Exercise Prevents Angry Mood Induction but Does Not Change Angry Emotions.

INTRODUCTION: Exercise is well known to enhance a variety of mood states, but few studies have been specifically designed to investigate whether acute aerobic exercise alters feelings of anger. The goal of this study was to determine the magnitude of the effects of acute exercise on both angry mood and angry emotions. METHODS: Angry mood and angry emotions were assessed in 16 men with elevated trait anger who viewed a variety of emotionally evocative scenic pictures before and after 30 min of moderate- to vigorous-intensity aerobic exercise. Angry mood, captured by self-reports of state anger, angry emotions, as indexed by event-related brain activity (e.g., early posterior negativity and late positive potential), and self-reports of anger intensity were measured. RESULTS: The results indicate that acute exercise both 1) reduces angry mood and 2) mitigates angry mood induction but does not change the intensity of angry emotions or the associated event-related potential responses to anger-inducing pictures in college-age men who have elevated trait anger. CONCLUSION: Future studies should explore the mechanisms underlying the effect of exercise on preventing angry mood induction, consider alternative anger induction methods that might induce higher levels of angry emotions, and test the effects of chronic exercise training on anger and its expression.

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.

Declining Physical Activity and Motivation from Middle School to High School.

PURPOSE: The purpose of this study was to determine whether naturally occurring changes in intrinsic motivation, behavioral regulation, and goals mitigate declining physical activity among adolescents. METHODS: Latent growth modeling was applied in tests of change in intrinsic motivation, facets of behavioral regulation, and their interactions with goals on change in physical activity measured by accelerometer in a cohort of 260 boys and girls evaluated longitudinally from sixth through ninth grades. RESULTS: Physical activity declined less in youths who maintained higher intrinsic motivation or integrated regulation, but only when they maintained higher enjoyment goal compared with other students. Physical activity also declined less in students who maintained higher intrinsic motivation or integrated motivation and had bigger declines in appearance goal (or social and competence goals with intrinsic motivation) compared with students who maintained higher levels of those goals. The interactions correspond to 1 to 2 min·h less decrease in physical activity. CONCLUSIONS: Consistent with Self-Determination Theory, the findings encourage interventions that target autonomous motivation among youths. The results extend prior evidence in three ways. First, the cohort was tracked for 3 yr using an objective measure of physical activity. Second, influences of intrinsic motivation and integrated regulation on changing physical activity were not direct. They interacted with changing goals, indicating that interventions should also focus on specific goals for physical activity as effect modifiers. Third, interventions focused on autonomous motivation should consider that controlled, introjected motivation may also interact with goals to influence physical activity during the transition between middle school and high school.

Naturally-occurring changes in social-cognitive factors modify change in physical activity during early adolescence.

PURPOSE: To determine whether naturally-occurring changes in children's motives and beliefs are associated with the steep decline in physical activity observed from childhood to early adolescence. METHODS: Latent growth modeling was applied in longitudinal tests of social-cognitive influences, and their interactions, on physical activity in a large cohort of boys and girls evaluated annually between 5th and 7th grades. RESULTS: Measurement equivalence of motives and beliefs was confirmed between boys and girls. After adjustment for gender and maturity differences, physical activity declined less in children who reported the least decreases in self-efficacy for overcoming barriers to activity and perceived parental support. Physical activity also declined less in students who persistently felt they had more parental and friend support for activity compared to those who reported the largest decrease in support from friends. After further adjustment for race, the decline in physical activity was less in those who had the largest decrease in perceived barriers and maintained a favorable perception of their neighborhood environment. Changes in enjoyment and social motives were unrelated to change in physical activity. CONCLUSION: Using an objective measure of physical activity, we confirm that naturally-occurring changes in children's beliefs about barriers to physical activity and their ability to overcome them, as well as perceptions of their neighborhood environment and social support, are concurrent with age-related declines in children's physical activity. The longitudinal findings confirm these putative social-cognitive mediators as plausible, interacting targets of interventions designed to mitigate the marked decline in physical activity that occurs during the transition between elementary and middle schools.

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.

Periodic Change in Sufficient Physical Activity: A 2-Year Study of a Multi-Ethnic Cohort.

BACKGROUND: Measuring the way people vary across time in meeting recommended levels of physical activity is a prerequisite to quantifying exposure in outcome studies or identifying determinants of sufficient physical activity. The study determined whether distinct patterns of change in sufficient physical activity could be identified in a population. METHODS: A cohort (N = 497) from a random, multiethnic sample of adults living in Hawaii was assessed every 6 months for 2 years beginning spring 2004. Latent transition analysis classified people as sufficiently or insufficiently active each time. RESULTS: In the total cohort, odds that people would move from insufficient to sufficient activity (45% to 59%) at each 6-month transition were higher than odds they would move from sufficient to insufficient activity (8% to 13%). However, those odds, as well as types and amounts of physical activity, differed widely among and within 3 of 4 transition classes that represented 21% of the cohort. CONCLUSIONS: Point-prevalence of sufficient physical activity in the total cohort was similar to contemporary U.S. estimates. However, physical activity varied between and within subgroups of the cohort. Further research is needed using self-report and objective measures to determine patterns of change in sufficient physical activity in other representative cohorts.

Quantifying the placebo effect in psychological outcomes of exercise training: a meta-analysis of randomized trials.

BACKGROUND: The placebo effect could account for some or all of the psychological benefits attributed to exercise training. The magnitude of the placebo effect in psychological outcomes of randomized controlled exercise training trials has not been quantified. The aim of this investigation was to estimate the magnitude of the population placebo effect in psychological outcomes from placebo conditions used in exercise training studies and compare it to the observed effect of exercise training. METHODS: Articles published before 1 July 2013 were located using Google Scholar, MEDLINE, PsycINFO, and The Cochrane Library. To be included in the analysis, studies were required to have (1) a design that randomly assigned participants to exercise training, placebo, and control conditions and (2) an assessment of a subjective (i.e., anxiety, depression, energy, fatigue) or an objective (i.e., cognitive) psychological outcome. Meta-analytic and multi-level modeling techniques were used to analyze effects from nine studies involving 661 participants. Hedges' d effect sizes were calculated, and random effects models were used to estimate the overall magnitude of the placebo and exercise training effects. RESULTS: After adjusting for nesting effects, the placebo mean effect size was 0.20 (95% confidence interval [CI] -0.02, 0.41) and the observed effect of exercise training was 0.37 (95% CI 0.11, 0.63). CONCLUSION: A small body of research suggests both that (1) the placebo effect is approximately half of the observed psychological benefits of exercise training and (2) there is an urgent need for creative research specifically aimed at better understanding the role of the placebo effect in the mental health consequences of exercise training.

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.

Chronic exercise dampens hippocampal glutamate overflow induced by kainic acid in rats.

Our laboratory has previously reported that chronic, voluntary exercise diminishes seizure-related behaviors induced by convulsant doses of kainic acid. The present experiments tested the hypothesis that exercise exerts this protective effect through a mechanism involving suppression of glutamate release in the hippocampal formation. Following three weeks of voluntary wheel running or sedentary conditions, rats were injected with 10 mg/kg of kainic acid, and hippocampal glutamate was measured in real time using a telemetric, in vivo voltammetry system. A separate experiment measured electroencephalographic (EEG) activity following kainic acid treatment. Results of the voltammetry experiment revealed that the rise in hippocampal glutamate induced by kainic acid is attenuated in exercising rats compared to sedentary controls, indicating that the exercise-induced protection against seizures involves regulation of hippocampal glutamate release. The findings reveal the potential benefit of regular exercise in the treatment and prevention of seizure disorders and suggest a possible neurobiological mechanism underlying this effect.

Motivation and Behavioral Regulation of Physical Activity in Middle School Students.

PURPOSE: This study aimed to examine whether intrinsic motivation and behavioral self-regulation are related to physical activity during middle school. METHOD: Structural equation modeling was applied in cross-sectional and longitudinal tests of self-determination theory. RESULTS: Consistent with theory, hypothesized relations among variables were supported. Integrated regulation and intrinsic motivation were most strongly correlated with moderate-to-vigorous physical activity measured by an accelerometer. Results were independent of a measure of biological maturity. Construct validity and equivalence of measures were confirmed longitudinally between the sixth and seventh grades and between boys and girls, non-Hispanic Black and White children and overweight and normal-weight students. CONCLUSIONS: Measures of autonomous motivation (identified, integrated, and intrinsic) were more strongly related to physical activity in the seventh grade than measures of controlled motivation (external and introjected), implying that physical activity became more intrinsically motivating for some girls and boys as they moved through middle school. Nonetheless, change in introjected regulation was related to change in physical activity in the seventh grade, suggesting that internalized social pressures, which can be detrimental to sustained activity and well-being, also became motivating. These results encourage longer prospective studies during childhood and adolescence to clarify how controlled and autonomous motivations for physical activity develop and whether they respond to interventions designed to increase physical activity.

Change in weight and adiposity in college students: a systematic review and meta-analysis.

CONTEXT: The purpose of this systematic review and meta-analysis was to assess changes in body weight and relative adiposity (%FAT) during college and identify potential moderating variables. EVIDENCE ACQUISITION: A review of peer-reviewed articles published before June 28, 2013 identified 49 studies evaluating the effect of the first year of college on the dependent variables of body weight (137 effects from 48 studies) and %FAT (48 effects from 19 studies). Statistical analysis was conducted between July 1, 2013, and May 1, 2014. Effect sizes were calculated by subtracting the mean pre-test measurements from the mean post-test measurements. EVIDENCE SYNTHESIS: Participants' weight increased 1.55 kg (95% CI=1.3, 1.8 kg) during college, with a 1.17% increase in %FAT (95% CI=0.7, 1.6%). Meta-regression analysis concluded that changes in body weight and %FAT were positively associated with study duration, suggesting that effects measuring change over a longer duration yielded larger effects when compared to effects with shorter observations. Sex and baseline BMI were not associated with change in weight or %FAT after accounting for study duration. CONCLUSIONS: The increase in weight and %FAT during the college years is equal to 1.55 kg and 1.17%, respectively. Change in body weight during the first year of college is significantly less than that during the cumulative remaining years of college. By understanding the magnitude of change, appropriate prevention efforts can be designed for the college population, which may be beneficial in reducing adult overweight and obesity rates.

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.