Mechanisms by Which the Fun for Wellness Intervention May Promote Subjective Well-Being in Adults with Obesity: a Reanalysis Using Baseline Target Moderation.

Fun For Wellness (FFW) is a self-efficacy theory-based online behavioral intervention that aims to promote growth in physical activity and well-being. The FFW conceptual model for the promotion of subjective well-being posits that FFW exerts both a positive direct effect, and a positive indirect effect through well-being self-efficacy, on subjective well-being. Subjective well-being is defined in FFW as an individual's satisfaction with their status in seven key domains of their life. Well-being self-efficacy is defined in FFW as the degree to which an individual perceives that they have the capability to attain a positive status in seven key domains of their life. The objective of this study was to use baseline target moderation to assess variation in the impact of FFW on subjective well-being dimensions in adults with obesity. Data (N = 667) from the Well-Being and Physical Activity Study (ClinicalTrials.gov, identifier: NCT03194854) were reanalyzed. There was evidence that well-being self-efficacy at baseline moderated the direct effect of FFW on well-being self-efficacy at 30 days post-baseline for the occupational and psychological dimensions. Both of these findings suggest a "compensatory" effect. Similarly, there was evidence that well-being self-efficacy at baseline moderated the indirect effect of FFW on subjective well-being at 60 days post-baseline through well-being self-efficacy at 30 days post-baseline for the occupational and psychological dimensions. Both of these findings suggest a "compensatory" effect. Finally, there was evidence that well-being self-efficacy at baseline moderated the direct effect of FFW on subjective well-being at 60 days post-baseline for the community, occupational, and physical dimensions. Each of these three findings suggests some version of a "rich-get-richer" effect. In summary, results provide both supportive and unsupportive (i.e., interpersonal, economic, and overall dimensions) evidence regarding variation in the impact of the FFW intervention and should impact the design of future FFW trials.

A Systematic Review of eHealth Interventions to Promote Physical Activity in Adults with Obesity or Overweight.

Use of information and communication technology to improve health, known as eHealth, is an emerging concept in healthcare that may present opportunities to promote physical activity in adults with obesity. The purpose of this research was to systematically review eHealth intervention studies to promote physical activity in adults with obesity. Five electronic databases were used. Two authors screened articles, assessed risk of bias, and extracted data independently. A qualitative data synthesis for summarizing the findings was performed using harvest plots. In the search, 2276 articles were identified, and 18 studies met all inclusion criteria. Study quality ranged from poor to good. The included studies varied in intervention technology (e.g., web-based), physical activity assessment (e.g., device-based), and control group (e.g., wait-list). Behavioral change techniques used in the included studies were consistent with some techniques (e.g., self-monitoring) known as effective in face-to-face interventions, but more efficiently employed in eHealth using information and communication technology. Overall, this systematic review showed that a web-based or physical activity monitor-based eHealth intervention had the potential to effectively promote physical activity in adults with obesity. Some recommendations for future eHealth interventions to promote physical activity in adults with obesity were provided (e.g., use of theory, accelerometers).

Assessing the Relationship Between External Workloads and Noncontact Injuries During Summer Conditioning and Preseason Practice in National Collegiate Athletic Association Division 1 Football Players.

ABSTRACT: Burghardt, WP, Pfeiffer, KA, and Kuenze, C. Assessing the relationship between external workloads and noncontact injuries during summer conditioning and preseason practice in National Collegiate Athletic Association Division 1 football players. J Strength Cond Res 37(4): 816-822, 2023-The purpose of this study was to prospectively investigate the relationship between noncontact injuries and workload in collegiate football during summer conditioning and preseason training. Workload and noncontact injury data were collected over the summer conditioning and preseason practice periods for a Division 1 National Collegiate Athletic Association football team ( n = 34). Seven- and 21-day exponentially weighted moving averages (EWMA) were calculated daily for each athlete. The acute:chronic ratio (A:C ratio) of these 2 measures was also calculated daily. Injury rates for noncontact injuries were calculated for both periods. Continuous variable modeling (panel logistic regression and restricted cubic spline) was used to assess the relationship of EWMA A:C ratio and noncontact injury using a 3-day lag period. Athletic exposures (AEs) were defined as individual sport training, practice, or competition sessions. Nine injuries were observed (6.97/1,000 AEs), with 4 injuries resulting in lost time (3.09/1,000 AEs). The mean EWMA A:C ratio was 0.92 ± 0.41 (95% confidence interval: 0.03-2.09). Both the panel logistic regression and the restricted cubic spline models showed a significant relationship between EWMA A:C ratio and noncontact injuries. However, the odds ratio (14.16) in the logistic regression had a very large standard error (14.51) and a wide 95% confidence interval (1.90-105.49). The restricted cubic spline model had a pseudo R2 of 0.136. Injury occurrence at given EWMA ratio values was lower than reported in previous research. Although both continuous models demonstrated a significant relationship between the EWMA A:C ratio and subsequent noncontact injuries over the next 3 days, neither model had sufficient goodness of fit to warrant adoption at this time.

Longitudinal effects of growth restriction on the murine gut microbiome and metabolome.

Undernutrition-induced growth restriction in the early stages of life increases the risk of chronic disease in adulthood. Although metabolic impairments have been observed, few studies have characterized the gut microbiome and gut-liver metabolome profiles of growth-restricted animals during early-to-mid-life development. To induce growth restriction, mouse offspring were either born to gestational undernutrition (GUN) or suckled from postnatal undernutrition (PUN) dams fed a protein-restricted diet (8% protein) or control diet (CON; 20% protein) until weaning at postnatal age of 21 days (PN21). At PN21, all mice were fed the CON diet until adulthood (PN80). Livers were collected at PN21 and PN80, and fecal samples were collected weekly starting at PN21 (postweaning week 1) until PN80 (postweaning week 5) for gut microbiome and metabolome analyses. PUN mice exhibited the most alterations in gut microbiome and gut and liver metabolome compared with CON mice. These mice had altered fecal microbial ß-diversity (P = 0.001) and exhibited higher proportions of Bifidobacteriales [linear mixed model (LMM) P = 7.1 × 10-6), Clostridiales (P = 1.459 × 10-5), Erysipelotrichales (P = 0.0003), and lower Bacteroidales (P = 4.1 × 10-5)]. PUN liver and fecal metabolome had a reduced total bile acid pool (P < 0.01), as well as lower abundance of riboflavin (P = 0.003), amino acids [i.e., methionine (P = 0.0018), phenylalanine (P = 0.0015), and tyrosine (P = 0.0041)], and higher excreted total peptides (LMM P = 0.0064) compared with CON. Overall, protein restriction during lactation permanently alters the gut microbiome into adulthood. Although the liver bile acids, amino acids, and acyl-carnitines recovered, the fecal peptides and microbiome remained permanently altered into adulthood, indicating that inadequate protein intake in a specific time frame in early life can have an irreversible impact on the microbiome and fecal metabolome.NEW & NOTEWORTHY Undernutrition-induced early-life growth restriction not only leads to increased disease risk but also permanently alters the gut microbiome and gut-liver metabolome during specific windows of early-life development.

Determining independence and associations among various cardiovascular disease risk factors in 9-12 years old school-children: a cross sectional study.

BACKGROUND: Cardiovascular disease (CVD) risk assessment of children typically includes evaluating multiple CVD risk factors some of which tend to correlate each other. However, in older children and young adolescents, there are little data on the level of independence of CVD risk factors. The purpose of this study was to examine the relationships among various CVD risk factors to determine the level of independence of each risk factor in a sample of 5th-grade public school students. METHOD: A cross-sectional analysis of 1525 children (856 girls and 669 boys; age: 9-12 years) who participated in baseline CVD risk assessment for the (S)Partners for Heart Health program from 2010 - 2018. Thirteen CVD risk factor variables were used in the analysis and included blood lipids [low-density lipoprotein (LDL), high-density lipoprotein (HDL), total cholesterol (TC), and triglycerides], resting systolic and diastolic blood pressure (BP); anthropometrics [height, weight, body mass index (BMI), % body fat, waist circumference (WC)]. Additionally, acanthosis nigricans (a marker insulin resistance and diabetes), and cardiorespiratory fitness (VO2 ml/kg) was estimated using the PACER. Descriptive statistics, bivariate Pearson correlations, and principal component analysis were used to determine the relationships among these variables and the independence. RESULTS: Parallel analysis indicated two components should be extracted. Among the two components extracted, WC, % body fat, and BMI loaded highest on component 1, which explained 34% of the total variance. Systolic BP and diastolic BP loaded predominantly on component 2 and accounted for 17% of the variance. Cardiorespiratory fitness, acanthosis nigricans, HDL, and triglycerides loaded highest on the first component (loadings between 0.42 and 0.57) but still suggest some non-shared variance with this component. Low-density lipoprotein had low loadings on each component. Factor loadings were stable across sex. CONCLUSION: Among the various CVD risk indicators, measures of adiposity loaded highest on the component that explained the largest proportion of variability in the data reinforcing the importance of assessing adiposity in CVD risk assessment. In addition, blood pressure loaded highest on the second component, suggesting their relative independence when assessing CVD risk. The data also provide support and rationale for determining what CVD risk factors to include- based on resource needs. For example, researchers or public health programs may choose to assess WC instead of lipid profile for cardiovascular related problems if ease of assessment and cost are considerations.

Protocol for a multicenter-cluster randomized clinical trial of a motor skills intervention to promote physical activity and health in children: the CHAMP afterschool program study.

BACKGROUND: Promoting health-enhancing and sustainable physical activity levels across childhood and adolescence contribute to positive health outcomes as an adult. This study will aim to: a) examine the immediate (pre- to post-intervention) and sustained (1-year post-intervention follow-up) effects of the Children's Health Activity Motor Program-Afterschool Program (CHAMP-ASP) on physical activity, motor competence, and perceived motor competence relative to the comparison ASP, b) examine the immediate and sustained effects of CHAMP-ASP on secondary health outcomes, specifically health-related physical fitness (i.e., cardiorespiratory fitness, muscular strength, percent body fat) and weight status compared to children in the comparison ASP, and c) determine if perceived motor competence mediates the effect of CHAMP-ASP on moderate-to-vigorous physical activity. METHODS: This multicenter cluster randomized trial will be implemented by ASP staff and will be conducted in ASPs located in two city-based cohorts: East Lansing/Lansing and Ann Arbor/Ypsilanti, Michigan. Children (N = 264) who are K-2 graders will participate 35 min/day X 3 days/week for 19 weeks (1995 min) in their afterschool movement program (i.e., CHAMP-ASP vs. comparison). The research team will train ASP staff to implement the program, which will be delivered within the existing ASP offering. Measures of physical activity (accelerometer), motor competence (process and product measures of fundamental motor skills), health-related fitness, perceived motor competence, and anthropometry will be collected pre-, immediately post-, and one-year post-intervention. Random-effects models will be used to assess the clustered longitudinal effect of the intervention on outcome measures. DISCUSSION: The long-term goal is to provide a sustainable, ecologically-relevant, and evidence-based program during the early elementary years that can be delivered by ASP staff, is health-enhancing, and increases physical activity in children. Findings hold the potential to help shape public health and educational policies and interventions that support healthy development and active living during the early years. TRIAL REGISTRATION: ClinicalTrials.gov Identifier NCT05342701 . ETHICS AND DISSEMINATION: Ethical approval was obtained through the Health Sciences and Behavioral Sciences IRB, University of Michigan (HUM00208311). The CHAMP-ASP study is funded by the National Institutes of Health. Findings will be disseminated via print, online media, dissemination events, and practitioner and/or research journals.

Developmental disparities in sedentary time by period of the day among US youth: a cross-sectional study.

BACKGROUND: Definitive evidence shows sedentary time (ST) is an independent risk factor for chronic disease, irrespective of physical activity. Despite calls to limit youth ST, studies demonstrate a spike in ST at the transition from childhood to adolescence. Identifying periods of the day (e.g., before school, during school, afterschool, and evenings) during which ST is higher in adolescents vs. children-that is, specifying when within daily routines ST disparities emerge-may be important to inform intervention strategies, as periods of the day correspond with variations in setting and supervision. The purpose of this study was to examine device-assessed ST engagement by period of day and developmental stage in a nationally representative sample of United States youth. METHODS: Youth (N = 2,972 between 6-18 years) from the 2003-2004 and 2005-2006 waves of NHANES reported demographic variables and wore an accelerometer for seven consecutive days to determine ST. Linear regression analyses were applied to study associations between ST and developmental stage (childhood or adolescence) by period of the week and weekend days, while controlling for sex, race/ethnicity, annual family income, and body mass index. RESULTS: Adjusted linear regressions (p-values < 0.0001) showed that adolescents were more sedentary than children during school, afterschool, and weekday evening periods as well as all the weekend periods. However, during school (36.3 ± 7.3 vs. 28.2 ± 7.2 min/hour; b = -7.4 [-8.1, -6.6]) and afterschool periods (31.1 ± 7.7 vs. 22.7 ± 7.0 min/hour; b = -7.8 [-8.6, -7.0]) showed the largest weekly ST disparities by developmental stage. Overall, the during school and after school hours constitute most (during school = 35% and afterschool = 16%) of the weekly ST disparity between children and adolescents. CONCLUSIONS: Our data provide interventionists with estimates of the potential for ST reduction in each setting and period of the day among US adolescents. Future research should gather information about the barriers and facilitators of ST in adolescents by period of the day to help understand factors driving disparities.

A consensus method for estimating physical activity levels in adults using accelerometry.

Identifying the best analytical approach for capturing moderate-to-vigorous physical activity (MVPA) using accelerometry is complex but inconsistent approaches employed in research and surveillance limits comparability. We illustrate the use of a consensus method that pools estimates from multiple approaches for characterising MVPA using accelerometry. Participants (n = 30) wore an accelerometer on their right hip during two laboratory visits. Ten individual classification methods estimated minutes of MVPA, including cut-point, two-regression, and machine learning approaches, using open-source count and raw inputs and several epoch lengths. Results were averaged to derive the consensus estimate. Mean MVPA ranged from 33.9-50.4 min across individual methods, but only one (38.9 min) was statistically equivalent to the criterion of direct observation (38.2 min). The consensus estimate (39.2 min) was equivalent to the criterion (even after removal of the one individual method that was equivalent to the criterion), had a smaller mean absolute error (4.2 min) compared to individual methods (4.9-12.3 min), and enabled the estimation of participant-level variance (mean standard deviation: 7.7 min). The consensus method allows for addition/removal of methods depending on data availability or field progression and may improve accuracy and comparability of device-based MVPA estimates while limiting variability due to convergence between estimates.

Feelings of safety during daytime walking: associations with mental health, physical activity and cardiometabolic health in high vacancy, low-income neighborhoods in Detroit, Michigan.

INTRODUCTION: Individuals living in low-income neighborhoods have disproportionately high rates of obesity, Type-2 diabetes, and cardiometabolic conditions. Perceived safety in one's neighborhood may influence stress and physical activity, with cascading effects on cardiometabolic health. METHODS: In this study, we examined relationships among feelings of safety while walking during the day and mental health [perceived stress (PSS), depression score], moderate-to-vigorous physical activity (PA), Body Mass Index (BMI), and hemoglobin A1C (A1C) in low-income, high-vacancy neighborhoods in Detroit, Michigan. We recruited 69 adults who wore accelerometers for one week and completed a survey on demographics, mental health, and neighborhood perceptions. Anthropometrics were collected and A1C was measured using A1CNow test strips. We compiled spatial data on vacant buildings and lots across the city. We fitted conventional and multilevel regression models to predict each outcome, using perceived safety during daytime walking as the independent variable of interest and individual or both individual and neighborhood-level covariates (e.g., number of vacant lots). Last, we examined trends in neighborhood features according to perceived safety. RESULTS: In this predominantly African American sample (91%), 47% felt unsafe during daytime walking. Feelings of perceived safety significantly predicted PSS (ß = - 2.34, p = 0.017), depression scores (ß = - 4.22, p = 0.006), and BMI (ß = - 2.87, p = 0.01), after full adjustment. For PA, we detected a significant association for sex only. For A1C we detected significant associations with blighted lots near the home. Those feeling unsafe lived in neighborhoods with higher park area and number of blighted lots. CONCLUSION: Future research is needed to assess a critical pathway through which neighborhood features, including vacant or poor-quality green spaces, may affect obesity-via stress reduction and concomitant effects on cardiometabolic health.

School-based interventions modestly increase physical activity and cardiorespiratory fitness but are least effective for youth who need them most: an individual participant pooled analysis of 20 controlled trials.

OBJECTIVES: To determine if subpopulations of students benefit equally from school-based physical activity interventions in terms of cardiorespiratory fitness and physical activity. To examine if physical activity intensity mediates improvements in cardiorespiratory fitness. DESIGN: Pooled analysis of individual participant data from controlled trials that assessed the impact of school-based physical activity interventions on cardiorespiratory fitness and device-measured physical activity. PARTICIPANTS: Data for 6621 children and adolescents aged 4-18 years from 20 trials were included. MAIN OUTCOME MEASURES: Peak oxygen consumption (VO2Peak mL/kg/min) and minutes of moderate and vigorous physical activity. RESULTS: Interventions modestly improved students' cardiorespiratory fitness by 0.47 mL/kg/min (95% CI 0.33 to 0.61), but the effects were not distributed equally across subpopulations. Girls and older students benefited less than boys and younger students, respectively. Students with lower levels of initial fitness, and those with higher levels of baseline physical activity benefitted more than those who were initially fitter and less active, respectively. Interventions had a modest positive effect on physical activity with approximately one additional minute per day of both moderate and vigorous physical activity. Changes in vigorous, but not moderate intensity, physical activity explained a small amount (~5%) of the intervention effect on cardiorespiratory fitness. CONCLUSIONS: Future interventions should include targeted strategies to address the needs of girls and older students. Interventions may also be improved by promoting more vigorous intensity physical activity. Interventions could mitigate declining youth cardiorespiratory fitness, increase physical activity and promote cardiovascular health if they can be delivered equitably and their effects sustained at the population level.

Acute Cardiometabolic and Perceptual Responses to Individual and Group-Based Body-Weight Resistance Exercise in Girls.

Girls' acute responses to group-based high-intensity interval exercise (HIIE) are not well characterized. PURPOSE: To compare acute responses to treadmill-based HIIE (TM) and body-weight resistance exercise circuit (CIRC) and to CIRC performed in a small-group setting (group CIRC). METHOD: Nineteen girls (9.1 [1.1] y) completed exercise testing on a TM to determine peak oxygen uptake, peak heart rate (HRpeak), and maximal aerobic speed. The TM involved eight 30-second sprints at 100% maximal aerobic speed. The CIRC consisted of 8 exercises of maximal repetitions performed for 30 seconds. Each exercise bout was followed by 30 seconds of active recovery. The blood lactate concentration was assessed preexercise and postexercise. The ratings of perceived exertion, affective valence, and enjoyment were recorded at preexercise, Intervals 3 and 6, and postexercise. RESULTS: The mean heart rate was higher during group CIRC (92% [7%] HRpeak) than CIRC (86% [7%] HRpeak) and TM (85% [4%] HRpeak) (ηp2 = .49). The mean oxygen uptake equaled 76% (11%) of the peak oxygen uptake for CIRC and did not differ from TM (d = 0.02). The CIRC elicited a greater postexercise blood lactate concentration versus TM (5.8 [1.7] vs 1.4 [0.4] mM, d = 3.61). The perceptual responses were similar among conditions (P > .05), and only the rating of perceived exertion increased during exercise (ηp2 = .78). CONCLUSION: Whether performed individually or in a small group, CIRC represents HIIE and may be a feasible alternative to running-based HIIE.

Measurement of Physical Activity Self-Efficacy in Adults With Obesity: A Latent Variable Approach to Explore Dimensionality, Temporal Invariance, and External Validity.

The objective of this study was to improve the measurement of physical activity self-efficacy (PASE) in adults with obesity. To accomplish this objective, a latent variable approach was used to explore dimensionality, temporal invariance, and external validity of responses to a newly developed battery of PASE scales. Data (Nbaseline = 461 and N30 days postbaseline = 427) from the Well-Being and Physical Activity Study (ClinicalTrials.gov, identifier: NCT03194854), which deployed the Fun For Wellness intervention, were analyzed. A two-dimensional factor structure explained responses to each PASE scale at baseline. There was strong evidence for at least partial temporal measurement invariance for this two-dimensional structure in each PASE scale. There was mixed evidence that the effectiveness of the Fun For Wellness intervention exerted a direct effect on latent PASE in adults with obesity at 30 days postbaseline (i.e., external validity) of this two-dimensional structure.

Metabolic risk associated with liver enzymes, uric acid, and hemoglobin in adolescents.

BACKGROUND: The associations of renal, hepatic, and hematologic markers with metabolic risk (MR) have already been shown in adolescents. However, it is still controversial which marker best predicts metabolic changes in youth. The aim of this study was to verify the association of MR with alanine aminotransferase (ALT), aspartate aminotransferase (AST), uric acid, and hemoglobin (Hb) in adolescents. METHODS: We evaluated 1713 Brazilian adolescents aged 10 to 17 years. MR was calculated using a continuous metabolic risk score, including the sum of Z-scores of waist circumference, systolic blood pressure, fasting glucose, high-density lipoproteins, triglycerides, and cardiorespiratory fitness. Cutoff points were set for MR prediction for five metabolic components (ALT, AST, AST/ALT ratio, uric acid, and Hb). RESULTS: MR was strongly associated with increased uric acid (odds ratio [OR]: 2.50; 95% confidence interval [CI]: 1.74-3.59), ALT (OR: 2.64; 95% CI: 1.63-4.27), and AST levels (OR: 2.53; 95% CI: 1.24-5.18). Uric acid was shown to be the best predictor for MR (sensitivity: 55.79%; specificity: 61.35%; area under the curve: 0.616). CONCLUSION: Elevated hepatic, renal, and hematological markers were associated with MR in adolescents, especially ALT, AST, and uric acid levels. IMPACT: Elevated hepatic, renal, and hematological markers were associated with metabolic risk in adolescents, especially ALT, AST, and uric acid levels. It is still controversial which marker best predicts metabolic changes in adolescents. In addition, association of Hb with metabolic risk is under-studied in this population. It is important to further investigate the relationship between elevated Hb and hepatic markers, since there are key aspects not addressed yet. Our results highlight the importance of creating public health policies aimed to child and adolescent population, to prevention of metabolic disorders from an early age.

Preschoolers exhibit greater on-task behavior following physically active lessons on the approximate number system.

OBJECTIVE: To determine how the dual-task nature of incorporating physical activity with instructional activities immediately impacts acuity of the approximate number system and on-task behavior in preschoolers. METHODS: Using a randomized within-participants repeated-measures crossover design, 51 children completed an approximate number system task before and after either 20-min of physically active instruction corresponding to 38% heart rate reserve (HRR; light-to-moderate intensity) or conventional sedentary instruction at corresponding to 21% HRR (very light intensity). RESULTS: Findings revealed that preschool-aged children exhibited similar learning and greater on-task behavior following a single bout of physically active instruction relative to conventional sedentary instruction. Overall, preschoolers accrued 931.3 ± 8.2 more steps and an additional 9 minutes at or above light-intensity activity during the physically active instruction. CONCLUSION: Accordingly, these findings suggest that the dual-task nature of physically active learning does not compromise learning, reduces the need for redirecting off-task behavior, and ultimately allows children to avoid sedentary behavior in educational contexts.

Study of active neighborhoods in Detroit (StAND): study protocol for a natural experiment evaluating the health benefits of ecological restoration of parks.

BACKGROUND: Individuals living in deprived inner cities have disproportionately high rates of cancers, Type 2 diabetes and obesity, which have stress- and physical inactivity-related etiologies. This study aims to quantify effects of ecological park restoration on physical activity, stress and cardio-metabolic health outcomes. METHODS: The Study of Active Neighborhoods in Detroit is a quasi-experimental, longitudinal panel natural experiment with two conditions (restored park intervention (INT) and control (CNT)) and annual measurements at baseline and 3-years post-restoration. Individuals (sampled within 500 m of an INT/CNT park) serve as the unit of analysis. Restoration (n = 4 parks) involves replacing non-native plants and turf with native plants; creating trails; posting signage; and leading community stewardship events. The CNT condition (n = 5) is an unmaintained park, matched to INT based on specified neighborhood conditions. Recruitment involves several avenues, with a retention goal of 450 participants. Park measures include plant/avian diversity; usage of the park (SOPARC); signs of care; auditory environment recordings; and visual greenness using 360 imagery. Health outcomes include device-based physical activity behavior (primary outcome); salivary cortisol (secondary outcome); and several downstream health outcomes. Exposure to the INT will be assessed through visual contact time and time spent in the park using GPS data. Changes in health outcomes between years and INT versus CNT will be tested using generalized linear (mixed) models. DISCUSSION: Our study will examine whether restored urban greenspaces increase physical activity and lower stress, with public health planning implications, where small changes in neighborhood greenspaces may have large health benefits in low-income neighborhoods. STUDY REGISTRATION: Registration: OSF Preregistration registered March 31, 2020. Accessible from https://osf.io/surx7.

Space-time analysis of unhealthy food advertising: New Zealand children's exposure and health policy options.

Reducing children's exposure to unhealthy food advertising is an accepted strategy to end childhood obesity. This study aimed to (i) measure children's space-time exposures to unhealthy food advertising in public outdoor spaces, using GPS and wearable cameras; and (ii) test effectiveness of banning options. We compiled data (collected July 2014-June 2015) on 138 12-year-old children in Wellington, New Zealand, using wearable cameras and GPS devices worn over 4 days. In 2017-18, we linked 59 150 images taken in public outdoor spaces to GPS data. Of these, 1631 contained unhealthy food advertising exposures, defined as ≥50% of an advertisement observed in each image. We examined spatial patterns using kernel density mapping and graphed space-time trends. We interpolated a kriged exposure rate across Wellington to estimate exposure reductions for potential bans. Children were exposed to 7.4 (95% CI 7.0-7.8) unhealthy food advertisements/hour spent in outdoor public spaces. Exposures occurred in shopping centres, residential areas and sports facilities, commonly involving fast food, sugary drinks and ice cream. Peak exposure times were weekend afternoons/evenings and weekdays before/after school. In Wellington, we estimated that banning such advertising within 400 m of playgrounds would yield a 33% reduction in exposure, followed by in residential areas (27%), within 400 m of schools (25%), and 50% for a ban combining all above. This work documents the extent of children's exposure to unhealthy food advertising and the potential impact of bans. Given the ubiquity of advertising in public spaces, this New Zealand research offers innovative methods and findings likely relevant in other jurisdictions.

Cardiometabolic and Perceptual Responses to Body-Weight Resistance High-Intensity Interval Exercise in Boys.

The majority of studies examining children's responses to high-intensity interval exercise primarily utilized running; however, this modality does not require/include other important aspects of physical activity including muscular fitness. PURPOSE: To compare acute responses between a body weight resistance exercise circuit (CIRC) and treadmill-based (TM) high-intensity interval exercise. METHOD: A total of 17 boys (age = 9.7 [1.3] y) completed a graded exercise test to determine peak heart rate, peak oxygen uptake (VO2peak), and maximal aerobic speed. Sessions were randomized and counterbalanced. CIRC required 2 sets of 30-second maximal repetitions of 4 exercises. TM included eight 30-second bouts of running at 100% maximal aerobic speed. Both included 30-second active recovery between bouts. Blood lactate concentration was measured preexercise and postexercise. Rating of perceived exertion, affective valence, and enjoyment were recorded preexercise, after intervals 3 and 6, and postexercise. RESULTS: Participants attained 88% (5%) peak heart rate and 74% (9%) VO2peak for CIRC and 89% (4%) peak heart rate and 81% (6%) VO2peak for TM, with a significant difference in percentage of VO2peak (P = .003) between protocols. Postexercise blood lactate concentration was higher following CIRC (5.0 [0.7] mM) versus TM (2.0 [0.3] mM) (P < .001). Rating of perceived exertion, affective valence, and enjoyment responses did not differ between protocols (P > .05). CONCLUSION: HR responses were near maximal during CIRC, supporting that this body-weight circuit is representative of high-intensity interval exercise.

Cross-generational comparability of hip- and wrist-worn ActiGraph GT3X+, wGT3X-BT, and GT9X accelerometers during free-living in adults.

ActiGraph accelerometers are frequently used to characterize physical activity, but free-living cross-generational comparability of newer models has not been verified. Participants (N = 70) wore GT9X and wGT3X-BT accelerometers at the hip and a sub-sample (n = 54) wore GT9X and either wGT3X-BT or GT3X+ monitors at each wrist for 4 days. Vector magnitude (VM) counts, VM acceleration, Mean Amplitude Deviation (MAD), and Euclidean Norm Minus One (ENMO) were calculated (60-s epoch), and cut-points were used to determine percent of time spent in each intensity (sedentary/light, moderate, vigorous). Epoch-level correlation coefficients (r) were ≥0.73, and weighted kappa for intensity classifications ranged from 0.71 (ENMO, hip) to 0.98 (VM counts, non-dominant wrist). Monitors were equivalent for all outcomes, except ENMO (all locations/monitors), percent of time spent in sedentary/light (hip) and moderate (hip and non-dominant wrist) activity as classified by ENMO-based cut-points, and vigorous activity as classified by VM count cut-points (non-dominant wrist; p > 0.05). While epoch-level data were not identical, most outcomes were strongly related between models (e.g., MAD, VM) and equivalent once reduced to percent of time spent in each intensity. However, monitor output was not equivalent for the acceleration-based metric ENMO, suggesting that caution should be exercised when comparing this outcome among ActiGraph models.

Differences in associations of product- and process-oriented motor competence assessments with physical activity in children.

There is a positive association between motor competence and physical activity in child populations. Little is known about the relative variance explained in physical activity when process- versus product-oriented approaches are used for evaluating motor competence. This study aimed to examine associations between product- and process-oriented motor competence assessments and their capability to explain variance in physical activity. Participants included 167 children between the ages of 6-9 years. The run, jump, throw and kick were assessed using process-oriented (Test of Gross Motor Development-2nd edition) and product-oriented (run time, jump distance, throw and kick speed) assessments. Physical activity was assessed via Yamax Digi-walker NL2000 pedometers. Weak to strong correlations between process and product assessments were found (range: r = ± 0.01 to ±0.81). Statistically significant correlations between process and product scores were more frequent for the kick and throw. Both product- and process-oriented assessments were poor at explaining variance in pedometer assessed physical activity. No more than 4% of variance in physical activity could be explained by a single skill, regardless of whether product or process scores were used. Continued examination of associations between process- and product-oriented assessments may provide a more holistic understanding of motor competence across developmental time.

Development of cut-points for determining activity intensity from a wrist-worn ActiGraph accelerometer in free-living adults.

Despite recent popularity of wrist-worn accelerometers for assessing free-living physical behaviours, there is a lack of user-friendly methods to characterize physical activity from a wrist-worn ActiGraph accelerometer. Participants in this study completed a laboratory protocol and/or 3-8 hours of directly observed free-living (criterion measure of activity intensity) while wearing ActiGraph GT9X Link accelerometers on the right hip and non-dominant wrist. All laboratory data (n = 36) and 11 participants' free-living data were used to develop vector magnitude count cut-points (counts/min) for activity intensity for the wrist-worn accelerometer, and 12 participants' free-living data were used to cross-validate cut-point accuracy. The cut-points were: <2,860 counts/min (sedentary); 2,860-3,940 counts/min (light); and ≥3,941counts/min (moderate-to-vigorous (MVPA)). These cut-points had an accuracy of 70.8% for assessing free-living activity intensity, whereas Sasaki/Freedson cut-points for the hip accelerometer had an accuracy of 77.1%, and Hildebrand Euclidean Norm Minus One (ENMO) cut-points for the wrist accelerometer had an accuracy of 75.2%. While accuracy was higher for a hip-worn accelerometer and for ENMO wrist cut-points, the high wear compliance of wrist accelerometers shown in past work and the ease of use of count-based analysis methods may justify use of these developed cut-points until more accurate, equally usable methods can be developed.