The impact of ActiGraph's low-frequency extension filter on measurement of children's physical activity.

This study examines differences in accelerometer-based measurements of children's movement with and without applying ActiGraph's low-frequency extension (LFE) filter. Thirty children wore ActiGraph GT9X devices during structured physical activity (PA) periods. Raw accelerometry data for each activity period were processed with and without the LFE filter applied. For each activity period, paired t-tests were used to compare vector magnitude counts and minutes spent in moderate-to-vigorous physical activity (MVPA) with and without the LFE filter applied. Repeated measures MANOVA models were used for compositional data analysis of the percentage of time spent in sedentary behaviour and light, moderate, and vigorous PA with and without the LFE filter applied. Applying the LFE filter significantly increased vector magnitude counts and estimated minutes spent in MVPA for all activity periods when compared to the normal filter. For brisk walking, the LFE filter had a significant impact on the composition of time spent in sedentary behaviour and PA intensities. Children's activity data processed with the LFE filter may not be compatible with cut-points for activity levels developed with the normal filter, and caution should be taken when comparing children's activity levels or movement data between studies that do and do not use the LFE filter.

Autonomous motivation and action planning are longitudinally associated with physical activity during adolescence and early adulthood.

We examined the associations of autonomous motivation, controlled motivation, and physical activity (PA) planning with PA participation over six years across the adolescent-to-adult transition. Participants from the NEXT Generation Health Study, a nationally representative cohort study of U.S. 10th graders (N=2785), completed surveys yearly from 2010 to 2016 (four years post-high school). This study used data from Waves 2 (W2) through 7 (W7). Data were analyzed using growth models accounting for the complex survey design and controlling for sex, race/ethnicity, and body mass index. A piecewise growth model with two pieces (Piece 1: W2-W4; Piece 2: W4-W7) indicated that PA declined during late adolescence (W2-W4) (b=-0.31, ß=-0.22, p<.001), but did not decline after the transition into early adulthood (W4-W7) (b=-0.08, ß=-0.04, p=.052). Autonomous motivation was positively associated with PA at all waves (b=0.23-0.33, ß=1.90-4.37, p<.001). Controlled motivation was only positively associated with PA at W3 (12th grade) (b=0.13, ß=1.54, p=.011). PA planning varied significantly between individuals and significantly predicted PA (b=0.44, ß=0.21, p<.001). Although PA decreased significantly during late adolescence, PA did not decrease significantly after transitioning into early adulthood (one to four years post-high school). Elevated autonomous motivation and PA planning were consistently and significantly associated with higher PA, suggesting that these may be useful intervention targets during this adolescent-to-adult transition.

Assessment of adolescent weight status: Similarities and differences between CDC, IOTF, and WHO references.

OBJECTIVE: The research sought to determine the reliability of assessing adolescents' weight status based on three standard criteria, Centers for Disease Control and Prevention (CDC) growth charts, International Obesity Task Force (IOTF) standards, and the World Health Organization (WHO) growth references. METHODS: Data from the NEXT Generation Health Study US 10th grade cohort (n=2323, mean age=16.19years) starting in 2009 were used. Kappa statistics assessed agreement of assignment to weight categories. Associations of weight status with perceived body image, weight control intention, and general health were examined using linear regressions accounting for complex survey design. RESULTS: Kappas across weight status criteria were≥.89 and agreement exceeded 90% in all analyses. For all three criteria, overweight and obese participants, compared to normal weight, were significantly more likely to indicate fatter body image, higher weight control intention, and poorer general health; small differences in the regression coefficients by classification method were observed. CONCLUSION: The three criteria of weight status classifications substantially agreed. Associations of weight status with selected health correlates were similar regardless of the methods. Thus, the three classifications can be considered comparable for most research and practice purposes.

Individual, social, and environmental influences on the transitions in physical activity among emerging adults.

BACKGROUND: Youth's physical activity (PA) may change across developmental periods. Although previous studies have observed a decline in levels of PA during adolescence, few studies have explored trends in PA during the transition from adolescence to young adulthood and what factors may impact the transitional change. The purpose of this study was to examine changes and predictors of change over time in PA from 10(th) grade to post-high school. METHODS: The NEXT Generation Health Study recruited a nationally-representative cohort of US 10(th)-graders, and administered longitudinal surveys in four waves (years) to follow up the participants to their first year after high school. Using transition models, the self-reported outcomes, moderate-to-vigorous PA (MVPA) and vigorous PA (VPA) each of which was repeatedly measured by one question, were modelled in association with wave-4 environmental-status variables and time-varying covariates. RESULTS: There was a continuous decline in the proportion of respondents who met or exceeded the minimum recommended level for either MVPA (from 55.97 to 34.33 %) or VPA (from 65.96 to 54.90 %) from W1 to W4. Higher scores of peer PA, family support and VPA planning were prospectively associated with higher likelihood of meeting the MVPA/VPA recommendations. At wave 4, compared to those not working, attending 4-year colleges, or living on campus, participants working full/part time, not attending school or attending community-college level schools, and living at home or in own place were more likely to engage in MVPA. CONCLUSIONS: Peer PA, family support, self-regulatory skills, and environmental status after high school are critical factors that can promote MVPA/VPA among adolescents and emerging adults.

Trajectories of eating behaviors in a nationally representative cohort of U.S. adolescents during the transition to young adulthood.

BACKGROUND: Diets of U.S. adolescents and adults do not meet recommendations, increasing risk of chronic disease. This study examined trajectories and predictors of eating behaviors in U.S. youth from age 16-20 years, and evaluated longitudinal associations of eating behaviors with weight outcomes. METHODS: Data come from the first four waves (years) of the NEXT Generation Health Study, a nationally representative cohort of U.S. students in 10(th) grade during the 2009-2010 school year (n = 2785). Annual surveys queried frequency of food group intake (times/day of fruit and vegetables, whole grains, sugar-sweetened soda, sweet and salty snacks), and meal practices (days/week of breakfast, family meals, fast food, and television during meals). Body mass index (BMI, kg/m(2)) was calculated from self-reported height and weight. Adjusted generalized estimating equations and linear mixed models with multiple imputation for missing data estimated eating behavior trajectories overall and by baseline weight status (normal weight = 5 ≤ BMI%ile < 85, overweight = 85 ≤ BMI%ile < 95, obese = BMI%ile ≥ 95), accounting for the complex sampling design. Separate GEE models estimated longitudinal associations of food group frequencies with meal practices and of BMI with eating behaviors. RESULTS: Eating behaviors tracked strongly from wave 1-4 (residual intraclass correlation = 41% - 51%). Across all baseline weight categories, frequency of food group intake and meal practices decreased over time, except for fast food, which remained stable. Fruit/vegetable intake frequency was associated positively with family meals (ß ± SE = 0.33 ± 0.05) and breakfast (0.18 ± 0.03), and inversely with fast food (-0.31 ± 0.04), while whole grain intake frequency was associated positively with family meals (0.07 ± 0.02), television meals (0.02 ± 0.009) and breakfast (0.04 ± 0.01). Soda and snacks were positively associated with television meals (0.08 ± 0.008 and 0.07 ± 0.009, respectively) and fast food (0.24 ± 0.02 and 0.20 ± 0.03, respectively), while soda was inversely associated with breakfast frequency (-0.05 ± 0.01). Time-varying BMI was unrelated to eating behaviors other than an inverse association with time-varying snacks (-0.33 ± 0.12). CONCLUSIONS: Strong tracking over time supports the importance of early establishment of health-promoting eating behaviors in U.S. adolescents. Findings suggest meal practices may be important intervention targets. Lack of evidence for hypothesized associations of BMI and eating behaviors indicates the need for research confirming these findings using more precise measures of dietary intake.

Secular trends in moderate-to-vigorous physical activity in 32 countries from 2002 to 2010: a cross-national perspective.

BACKGROUND: Sufficient levels of moderate to vigorous physical activity (MVPA) give substantial health benefits to adolescents. This article examines trends in physical activity (PA) from 2002 to 2010 across 32 countries from Europe and North America. METHODS: Representative samples included 479 674 pupils (49% boys) aged 11 years (n = 156 383), 13 years (n = 163 729) and 15 years (n = 159 562). The trends in meeting the recommendations for PA (at least 60 min daily) were evaluated using logistic regression. RESULTS: There was a slight overall increase between 2002 and 2010 (17.0% and 18.6%, respectively). MVPA increased significantly (P ≤ 0.05) among boys in 16 countries. Conversely, nine countries showed a significant decrease. Among girls, 10 countries showed a significant increase (P ≤ 0.05). Eight countries showed a significant decrease. For all countries combined, girls were slightly less likely to show an increase in PA over time. CONCLUSIONS: The majority of adolescents do not meet current recommendations of PA. Further investment at national and international levels is therefore necessary to increase PA participation among children and adolescents and reduce the future health burden associated with inactivity.

Motives for Physical Activity among Adolescents in the Czech and Slovak Republics.

OBJECTIVES: Physical activity significantly contributes to overall health and the level of activity during adolescence has been associated with physical activity in adulthood. The aim of this paper was to analyse motives for young people undertaking leisure time physical activity in the Czech and Slovak Republics. METHODS: Eleven to fifteen year old schoolchildren (N=9,014; mean age=13.59) participating in the Health Behaviour in School-aged Children 2009/2010 study in the Czech and Slovak Republics completed 12 items measuring physical activity motivations. To analyse the factor structure of motives for physical activity, Confirmatory Factor Analysis (CFA) was conducted using Principal Component Analysis (PCA) with varimax rotation. RESULTS: Contrary to previous research that reported three main motives for physical activity (health, social, achievement), our study suggests four motives. The additional motive is a combination of internal and external motivations and was called the "Good Child Motive". CONCLUSIONS: Better understanding of motives behind physical activity or inactivity of young people could significantly contribute to evidence based planning and development of national strategies for public health and active living.

Trends in bullying, physical fighting, and weapon carrying among 6th- through 10th-grade students from 1998 to 2010: findings from a national study.

OBJECTIVES: We examined trends from 1998 to 2010 in bullying, bullying victimization, physical fighting, and weapon carrying and variations by gender, grade level, and race/ethnicity among US adolescents. METHODS: The Health Behavior in School-Aged Children surveys of nationally representative samples of students in grades 6 through 10 were completed in 1998 (n = 15,686), 2002 (n = 14,818), 2006 (n = 9229), and 2010 (n = 10,926). We assessed frequency of bullying behaviors, physical fighting, and weapon carrying as well as weapon type and subtypes of bullying. We conducted logistic regression analyses, accounting for the complex sampling design, to identify trends and variations by demographic factors. RESULTS: Bullying perpetration, bullying victimization, and physical fighting declined from 1998 to 2010. Weapon carrying increased for White students only. Declines in bullying perpetration and victimization were greater for boys than for girls. Declines in bullying perpetration and physical fighting were greater for middle-school students than for high-school students. CONCLUSIONS: Declines in most violent behaviors are encouraging; however, lack of decline in weapon carrying merits further attention.

Motivation and planning as mediators of the relation between social support and physical activity among U.S. adolescents: a nationally representative study.

BACKGROUND: More than half of U.S. high-school students do not meet the moderate and vigorous physical activity (MVPA) 5 hours per week recommendation. The purpose of this study was to determine how individual dimensions (motivation and planning) mediate the relationship of social context with physical activity by integrating available measures of personal characteristic including internal/external motivations (derived from Self-Determination Theory -SDT]) for MVPA, MVPA planning, peer MVPA, and parental support to better understand adolescent MVPA. METHODS: Survey responses of a nationally representative cohort of 11th graders (N=2439) in the NEXT Generation Health Study were analyzed with structural equation modeling. RESULTS: Adolescent MVPA was directly, significantly associated with MVPA planning (ß=0.17), peer MVPA (ß=0.21), and internal motivation (ß=0.50). Internal motivation was associated with peer MVPA (ß=0.31), parental support for MVPA (ß=0.16), and external motivation (ß=0.40). A significant relation between parental support and external motivation (ß=0.31) was also found. CONCLUSIONS: Adolescents with higher internal motivation and more active friends were more likely to engage in MVPA. The results are consistent with SDT and suggest that planning is an important construct for adolescent MVPA.

A hidden Markov modeling approach combining objective measure of activity and subjective measure of self-reported sleep to estimate the sleep-wake cycle.

Characterizing the sleep-wake cycle in adolescents is an important prerequisite to better understand the association of abnormal sleep patterns with subsequent clinical and behavioral outcomes. The aim of this research was to develop hidden Markov models (HMM) that incorporate both objective (actigraphy) and subjective (sleep log) measures to estimate the sleep-wake cycle using data from the NEXT longitudinal study, a large population-based cohort study. The model was estimated with a negative binomial distribution for the activity counts (1-minute epochs) to account for overdispersion relative to a Poisson process. Furthermore, self-reported measures were dichotomized (for each one-minute interval) and subject to misclassification. We assumed that the unobserved sleep-wake cycle follows a two-state Markov chain with transitional probabilities varying according to a circadian rhythm. Maximum-likelihood estimation using a backward-forward algorithm was applied to fit the longitudinal data on a subject by subject basis. The algorithm was used to reconstruct the sleep-wake cycle from sequences of self-reported sleep and activity data. Furthermore, we conduct simulations to examine the properties of this approach under different observational patterns including both complete and partially observed measurements on each individual.

Modeling of drinking and driving behaviors among adolescents and young adults in the United States: Complexities and Intervention outcomes.

Alcohol-impaired driving is a formidable public health problem in the United States, claiming the lives of 37 individuals daily in alcohol-related crashes. Alcohol-impaired driving is affected by a multitude of interconnected factors, coupled with long delays between stakeholders' actions and their impacts, which not only complicate policy-making but also increase the likelihood of unintended consequences. We developed a system dynamics simulation model of drinking and driving behaviors among adolescents and young adults. This was achieved through group model building sessions with a team of multidisciplinary subject matter experts, and a focused literature review. The model was calibrated with data series from multiple sources and replicated the historical trends for male and female individuals aged 15 to 24 from 1982 to 2020. We simulated the model under different scenarios to examine the impact of a wide range of interventions on alcohol-related crash fatalities. We found that interventions vary in terms of their effectiveness in reducing alcohol-related crash fatalities. In addition, although some interventions reduce alcohol-related crash fatalities, some may increase the number of drinkers who drive after drinking. Based on insights from simulation experiments, we combined three interventions and found that the combined strategy may reduce alcohol-related crash fatalities significantly without increasing the number of alcohol-impaired drivers on US roads. Nevertheless, related fatalities plateau over time despite the combined interventions, underscoring the need for new interventions for a sustained decline in alcohol-related crash deaths beyond a few decades. Finally, through model calibration we estimated time delays between actions and their consequences in the system which provide insights for policymakers and activists when designing strategies to reduce alcohol-related crash fatalities.

Shared and distinct parental influences on teen impaired driving in rural and suburban contexts: A mixed methods study of young drivers.

OBJECTIVE: To explore shared and distinct parental influences on rural and suburban adolescents' riding with an impaired driver (RWI) and driving while impaired (DWI) behaviors during high school. METHODS: Participants in the NEXT Generation Health Study (NEXT) were classified into four RWI/DWI trajectory classes (i.e., Abstainer, Escalator, Decliner, Persister) which described patterns of RWI/DWI from high school to emerging adulthood. A follow-up, in-depth, qualitative interview was conducted with a purposeful selection of participants from each trajectory class between March and September 2020. Guided by Ecodevelopmental Theory, the interview included questions which explored parent-teen influences on driving and RWI/DWI. RESULTS: Imposition of a curfew was a shared parental influence in rural and suburban contexts. Unique to the rural context, parent modeling of RWI/DWI was described as normative and occurring since childhood. CONCLUSIONS: Prevention interventions targeting parent RWI/DWI may reduce their children's risk for RWI/DWI among rural adolescents.

Longitudinal perspectives of riding with a cannabis-impaired driver.

OBJECTIVE: To explore decisions and perceptions of engaging in riding with a cannabis-impaired driver (RWI) during high school and young adulthood to build context around RWI-cannabis events. METHODS: Participants were sampled from the NEXT Generation Health Study (NEXT), a 7-year national cohort study of adolescent health behaviors. Four RWI and driving while impaired (DWI) trajectories classes (i.e., Abstainer, Escalator, Decliner, Persister) were previously derived.A theoretical model based on ecological systems theory guidedin-depth semi-structured interviews to includecomplex, social-developmental and environmental multi-level factors affectingpersonal experiences with RWI-cannabis during high school, after high school, and during young adulthood. Participants (n = 105) were purposively selected from each trajectory class for follow-up, in-depth, qualitative interviews. All interviews were conducted via Zoom between March and September 2020. RESULTS: Two unique themes emerged as facilitators of RWI-cannabis: "Driving Context" and "Trust in Driver". "Legal Concerns" and "Concerns with Safety Emerge with Age" were themes that described deterrents to RWI-cannabis. CONCLUSIONS: Current data suggest that youth RWI-cannabis occurs during daytime hours and while driving to everyday activities. Youth report legal concerns as a potential deterrent to RWI-cannabis in high school and concerns for safety emerge in young adulthood. The multifaceted nature of RWI-cannabis among young drivers identifies potential complexities for programming designed to reduce RWI/DWI-cannabis.

Ethnic differences in perceptions of body satisfaction and body appearance among U.S. schoolchildren: a cross-sectional study.

BACKGROUND: Perceived body appearance and body satisfaction are potentially related to weight problems and poor health. The purpose of this study was to examine how gender, and ethnic differences in body satisfaction, perceived body appearance and weight status change by age in a representative sample of U.S. adolescents 11-17 years old. METHODS: We used the US Health Behavior in School-Aged Children (HBSC) 2001 survey which assessed perceived body appearance, body satisfaction, self-reported body mass index (BMI) and socio-demographic indicators. The associations between age and perceived appearance, age and body satisfaction, and between z-transformed BMI and body satisfaction were analyzed using separate non-parametric regression models for both genders and the three ethnic groups. RESULTS: Body satisfaction did not vary significantly by age except for an increase with age in the proportion of Non-Hispanic White girls who perceived themselves as too fat. Although boys did not report being too fat unless their BMI was above the age- and gender-specific median, one third of Non-Hispanic White girls felt too fat at or below the age- and gender-specific median. Compared to other ethnicities, African-American students' perceived appearance was significantly more positive and they were less likely to perceive themselves overweight at higher BMI scores. However, during adolescence, the positive self-reported perceived appearance of African-American boys dropped substantially while it remained relatively stable in African-American girls. CONCLUSIONS: There were substantial differences in body satisfaction and perceived appearance across the three largest ethnic groups of school-age children in the U.S. Stability across age indicates that these perceptions are most likely established before the age of 10 and underline the importance of primary schools and parents in prevention. Special attention should be directed to the dramatic loss of positive perceived appearance among African-American boys.

Summer activity patterns among teenage girls: harmonic shape invariant modeling to estimate circadian cycles.

BACKGROUND: Physical activity as measured by activity counts over short time intervals across a 24 h period are often used to assess circadian variation. We are interested in characterizing circadian patterns in activity among adolescents and examining how these patterns vary by obesity status. New statistical approaches are needed to examine how factors affect different features of the circadian pattern and to make appropriate covariate adjustments when the outcomes are longitudinal count data. METHODS: We develop a statistical model for longitudinal or repeated activity count data that is used to examine differences in the overall activity level, amplitude (defined as the difference between the lowest and highest activity level over a 24 hour period), and phase shift. Using seven days of continuous activity monitoring, we characterize the circadian patterns and compare them between obese and non-obese adolescent girls. RESULTS: We find a statistically significant phase delay in adolescent girls who were obese compared with their non-obese counterparts. After the appropriate adjustment for measured potential confounders, we did not find differences in mean activity level between the two groups. CONCLUSION: New statistical methodology was developed to identify a phase delay in obese compared with non-obese adolescents. This new approach for analyzing longitudinal circadian rhythm count data provides a useful statistical technique to add to the repertoire for those analyzing circadian rhythm data.

Trajectories and Outcomes of Adolescents that Ride With an Impaired Driver/Drive While Impaired.

Introduction: For young drivers, independent transportation has been noted to offer them opportunities that can be beneficial as they enter early adulthood. However, those that choose to engage in riding with an impaired driver (RWI) and drive while impaired (DWI) over time can face negative consequences reducing such opportunities. This study examined the prospective association of identified longitudinal trajectory classes among adolescents that RWI and DWI with their later health, education, and employment in emerging adulthood. Methods: We analyzed all seven annual assessments (Waves, W1-W7) of the NEXT Generation Health Study, a nationally representative longitudinal study starting with 10th grade (2009-2010 school year). Using all seven waves, trajectory classes were identified by latent class analysis with RWI (last 12 months) and DWI (last 30 days) dichotomized as ≥once = 1 vs. none = 0. Results: Four RWI trajectories and four DWI trajectories were identified: abstainer, escalator, decliner, and persister. For RWI and DWI trajectories respectively, 45.0% (N=647) and 76.2% (N=1,657) were abstainers, 15.6% (N=226) and 14.2% (N=337) were escalators, 25.0% (N=352) and 5.4% (N=99) were decliners, and 14.4% (N=197) and 3.8% (N=83) persisters. RWI trajectories were associated with W7 health status (χ2=13,20, p<.01) and education attainment (χ2=18.37, p<.01). Adolescent RWI abstainers reported better later health status than RWI escalators, decliners, and persisters; and decliners reported less favorable later education attainment than abstainers, escalators, and persisters. DWI trajectories showed no association with health status, education attainment, or employment. Conclusions: Our findings suggest the importance of later health outcomes of adolescent RWI. The mixed findings point to the need for more detailed understanding of contextual and time-dependent trajectory outcomes among adolescents engaging in RWI and DWI.

Mapping the complex causal mechanisms of drinking and driving behaviors among adolescents and young adults.

BACKGROUND: The proportion of motor vehicle crash fatalities involving alcohol-impaired drivers declined substantially between 1982 and 1997, but progress stopped after 1997. The systemic complexity of alcohol-impaired driving contributes to the persistence of this problem. This study aims to identify and map key feedback mechanisms that affect alcohol-impaired driving among adolescents and young adults in the U.S. METHODS: We apply the system dynamics approach to the problem of alcohol-impaired driving and bring a feedback perspective for understanding drivers and inhibitors of the problem. The causal loop diagram (i.e., map of dynamic hypotheses about the structure of the system producing observed behaviors over time) developed in this study is based on the output of two group model building sessions conducted with multidisciplinary subject-matter experts bolstered with extensive literature review. RESULTS: The causal loop diagram depicts diverse influences on youth impaired driving including parents, peers, policies, law enforcement, and the alcohol industry. Embedded in these feedback loops are the physical flow of youth between the categories of abstainers, drinkers who do not drive after drinking, and drinkers who drive after drinking. We identify key inertial factors, discuss how delay and feedback processes affect observed behaviors over time, and suggest strategies to reduce youth impaired driving. CONCLUSION: This review presents the first causal loop diagram of alcohol-impaired driving among adolescents and it is a vital first step toward quantitative simulation modeling of the problem. Through continued research, this model could provide a powerful tool for understanding the systemic complexity of impaired driving among adolescents, and identifying effective prevention practices and policies to reduce youth impaired driving.

The medicine use and corresponding subjective health complaints among adolescents, a cross-national survey.

BACKGROUND: Medicine use among children and young people is under-researched. Studies that investigated cross-national patterns in adolescents' medicine use practice are rare. This study aims to investigate adolescents' medicine use for corresponding health complaints in Europe and USA. METHODS: Nationally representative samples of adolescents from 19 countries and regions in Europe and USA completed an anonymous, standardised questionnaire as part of the Health Behaviour in School-aged Children 2005/2006 survey. The prevalence of health complaints and medicine use were determined. The influence of the frequency of medicine use, age, gender and country of residence, on the likelihood of medicine use was assessed using multilevel multivariate logistic regression, with separate analyses for boys and girls. RESULTS: Both health complaints and medicine use were common among adolescents. Medicine use was strongly associated with the frequency of health complaints. The prevalence of both medicine use and health complaints was higher among girls than boys. Boys and girls with weekly health complaints were both similarly likely to report elevated rates of medicine use. CONCLUSIONS: The findings indicated that adolescents who report more frequent recurrent health complaints are also more likely to report more frequent medicine use for their health complaints. Adolescent boys with weekly health complaints have the same risk of medicine use as girls with weekly health complaints. The importance of educating school-aged children to interpret their bodily feelings and complaints and to use medicines appropriately is of high priority.

Physical Activity and Enjoyment in Parent-Child Dyads During Shared Physical Activity.

Purpose: The purpose of this study was to compare objectively-measured physical activity (PA) and enjoyment of five shared PAs in parent-child dyads. Method: Thirty-one parent-child dyads (mean±SD; age, parents: 38.0 ± 6.6 years, children: 5.9 ± 1.7 years) completed separate PA sessions, which included five standardized PAs (brisk walking, jumping games, dancing, body-weight exercises, and tag games) in random order for each dyad. Parent and child moderate-to-vigorous PA (MVPA) and accelerometer counts per minute (CPM) were measured using Actigraph GT9X activity monitors. The Visual Analog Scale was used to assess enjoyment of children and parents. Repeated measures ANOVAs and paired t-tests determined differences in PA within and between children and parents for the activities, respectively. Friedman Tests with post hoc Wilcoxon signed-rank tests determined significant differences in enjoyment across the activities for children and parents and Wilcoxon signed-rank tests compared enjoyment between children and parents for each PA. Results: Jumping games resulted in the highest proportion of time spent in MVPA and highest overall CPM for children and parents (p < .05). Compared to parents, children spent proportionally more time in MVPA during jumping games, body-weight exercises, and tag games (all, p < .05). Tag games were the most enjoyable PA for children and parents (p < .05). Children enjoyed body-weight exercises more than parents (p < .05). Conclusions: Future indoor PA programs and research interventions that include parent-child dyads should consider implementing jumping games, body-weight exercises, and tag games during shared PA, which resulted in higher MVPA and enjoyment by both children and parents when compared to walking and dancing.

Validation of a continuous measure of cardiometabolic risk among adolescents.

OBJECTIVES: We validated a continuous cardiometabolic risk (CMR) measure among adolescents. METHODS: Five metabolic syndrome (MetS) components including waist circumference, triglycerides, high-density lipoprotein cholesterol, fasting blood glucose, and mean arterial pressure were assessed in a national cohort of U.S. adolescents (n=560; 16.5 ± 0.5 y/o at baseline) in 10th grade (2010, Wave 1 (W1)), and follow-up assessments four (W4) and seven (W7) years later. Separately by wave, linear regressions were fitted to each MetS component controlling for age, sex, and race/ethnicity, and yielded standardized residuals (Z-scores). Wave-specific component Z-scores were summed to obtain composite CMR Z-scores. Four- and seven-year CMR change (CMR-diff W1-W4 and W1-W7). and average CMR risk (CMR-avg; (W1 + W4)/2 and (W1 + W7)/2) were calculated using the CMR Z-scores. W7 MetS was determined using adult criteria. Student's t-test and receiver operating characteristic (ROC) curve were conducted. RESULTS: Participants meeting the adult criteria for MetS at W7 (74 of 416, 17.8%) had statistically significant (p<0.01) higher values for W1 CMR Z-scores (0.92 vs. -0.21), W4 CMR Z-scores (1.69 vs. -0.28), W7 CMR Z-scores (2.21 vs. -0.55), W1-W4 CMR-avg (1.53 vs. -0.27), W1-W7 CMR-diff (1.29 vs. -0.21), and W1-W7 CMR-avg (1.46 vs. -0.48) than those not meeting MetS criteria. Most results were similar for males and females in the sex-stratified analyses. The areas under the ROC curve were 0.61, 0.71, and 0.75 for W1, W4 and W7 Z-scores. CONCLUSIONS: Findings support the validity of the continuous CMR Z-scores calculated using linear regression in evaluating and monitoring CMR profiles from adolescence to early adulthood.