Disentangling associations between pubertal development, healthy activity behaviors, and sex in adolescent social networks.

With the onset of puberty, youth begin to choose their social environments and develop health-promoting habits, making it a vital period to study social and biological factors contextually. An important question is how pubertal development and behaviors such as physical activity and sleep may be differentially linked with youths' friendships. Cross-sectional statistical network models that account for interpersonal dependence were used to estimate associations between three measures of pubertal development and youth friendships at two large US schools drawn from the National Longitudinal Study of Adolescent to Adult Health.

Association of Time-of-Day Physical Activity With Incident Cardiovascular Disease: The UK Biobank Study.

Introduction: Early morning is characterized by an increased risk of cardiovascular events, a sudden rise in blood pressure, impaired endothelial function, and exacerbated hemodynamic changes during physical activity. The study aims to examine whether the time of day of physical activity is associated with incident cardiovascular disease (CVD).

Methods: We prospectively analyzed 83,053 participants in the UK Biobank with objectively measured physical activity and initially free of CVD.

Association of the time of day of peak physical activity with cardiovascular mortality: Findings from the UK Biobank study.

Cardiovascular physiology and pathophysiology display pronounced circadian rhythms. The study is designed to examine whether the time of day of physical activity is associated with cardiovascular mortality. We analyzed 94,489 UK Biobank adults with objectively measured physical activity, including 53,328 morning-type participants and 30,962 evening-type participants based on self-reported chronotypes.

Sleep Measurement Using Wrist-Worn Accelerometer Data Compared with Polysomnography.

This study determined if using alternative sleep onset (SO) definitions impacted accelerometer-derived sleep estimates compared with polysomnography (PSG). Nineteen participants (48%F) completed a 48 h visit in a home simulation laboratory. Sleep characteristics were calculated from the second night by PSG and a wrist-worn ActiGraph GT3X+ (AG).

School-Based Secondary Obesity Prevention for Eight- to Twelve-Year-Olds: Results from the Students, Nurses, and Parents Seeking Healthy Options Together Randomized Trial.

The primary aim of this randomized controlled trial, conducted in Minneapolis/St. Paul, Minnesota (2014-2019), was to evaluate the effects of a school-based, school nurse-delivered, secondary obesity prevention intervention to reduce excess weight gain among preadolescent children with obesity or at risk of developing obesity. Parent/child dyads ( = 132) were randomized to the 9-month Students, Nurses, and Parents Seeking Healthy Options Together (SNAPSHOT) intervention (32.

Sleep is Inversely Associated with Sedentary Time among Youth with Obesity.

Pathways underlying the sleep-obesity relationship in youth are poorly understood. In this study, we examined associations of sleep with sedentary time and moderate-to-vigorous physical activity (MVPA) among youth, stratified by weight category (obesity versus no obesity). A sub-aim examined whether controlling for screen time changed the sleep-sedentary time association.

Self-Efficacy, Not Peer or Parent Support, Is Associated With More Physical Activity and Less Sedentary Time Among 8- to 12-Year-Old Youth With Elevated Body Mass Index.

Background: Youth experience a decrease in physical activity (PA) and an increase in sedentary time during adolescence. Better understanding of factors associated with activity levels during preadolescence may inform interventions to minimize decline. This study compared the association of self-efficacy for PA, parent support for PA, and peer support for PA with moderate-to-vigorous PA (MVPA) and sedentary time among 8- to 12-year-old children with body mass index ≥75th percentile.

Estimating Sedentary Time from a Hip- and Wrist-Worn Accelerometer.

Purpose: This study aimed to determine the validity of existing methods to estimate sedentary behavior (SB) under free-living conditions using ActiGraph GT3X+ accelerometers (AG).

Methods: Forty-eight young (18-25 yr) adults wore an AG on the right hip and nondominant wrist and were video recorded during four 1-h sessions in free-living settings (home, community, school, and exercise). Direct observation videos were coded for postural orientation, activity type (e.

Walking cadence (steps/min) and intensity in 21-40 year olds: CADENCE-adults.

Background: Previous studies have reported that walking cadence (steps/min) is associated with absolutely-defined intensity (metabolic equivalents; METs), such that cadence-based thresholds could serve as reasonable proxy values for ambulatory intensities.

Purpose: To establish definitive heuristic (i.e.

School-based secondary prevention of overweight and obesity among 8- to 12-year old children: Design and sample characteristics of the SNAPSHOT trial.

Rising levels of severe obesity among children, worsening disparities by race and ethnicity and reluctance of primary care clinicians' to provide obesity management to children are compelling reasons to consider alternatives to primary care management of childhood obesity. The Students Nurses and Parents Seeking Healthy Options Together (SNAPSHOT) trial will test the efficacy of an elementary school-based, school nurse-led, healthy weight management program to reduce excess weight gain among children, 8- to 12-years old with a body mass index (BMI) ≥75th percentile, by increasing healthy dietary practices and physical activity and decreasing sedentary behaviors. SNAPSHOT has enrolled and randomized 132 child/parent dyads to either the: (1) 9-month SNAPSHOT intervention that includes four home visits, 14 kid groups held during out-of-school time and five parent groups or (2) a newsletter program consisting of monthly mailings and family-focused healthy lifestyle information.

The Influence of Friends and Psychosocial Factors on Physical Activity and Screen Time in Normal and Overweight Adolescents: A Mixed-Methods Analysis.

Background: Understanding factors that influence physical activity (PA) and sedentary behavior is crucial to develop interventions to improve adolescents' health-related behaviors.

Purpose: To compare the influence of friends and psychosocial factors on moderate-to-vigorous physical activity (MVPA) and screen time (ST) between normal weight (NW) and overweight (OW) adolescents.

Methods: In all, 21 OW and 21 NW adolescents wore accelerometers and completed questionnaires assessing MVPA, ST, and psychosocial variables.

Sedentary behavior and physical activity of young adult university students.

Movement and non-movement behaviors include sleep, sedentary behavior (SB) and physical activity (PA). While young adults are generally perceived as healthy, the level and relationship of SB and PA in college-age students has not been greatly explored. The purpose of this study was to objectively measure the levels of SB and PA in 18-20 year-old university students, record their self-reported extracurricular activities, and explore the relationship of all these with body mass index (BMI) and waist circumference (WC).

Impacts of active school design on school-time sedentary behavior and physical activity: A pilot natural experiment.

Background: Children spend a significant portion of their days in sedentary behavior (SB) and on average fail to engage in adequate physical activity (PA). The school built environment may influence SB and PA, but research is limited. This natural experiment evaluated whether an elementary school designed to promote movement impacted students' school-time SB and PA.

Youth Oriented Activity Trackers: Comprehensive Laboratory- and Field-Based Validation.

Background: Commercial activity trackers are growing in popularity among adults and some are beginning to be marketed to children. There is, however, a paucity of independent research examining the validity of these devices to detect physical activity of different intensity levels.

Objectives: The purpose of this study was to determine the validity of the output from 3 commercial youth-oriented activity trackers in 3 phases: (1) orbital shaker, (2) structured indoor activities, and (3) 4 days of free-living activity.

Cross-Validation of Two Accelerometers for Assessment of Physical Activity and Sedentary Time in Preschool Children.

Purpose: The purpose of this study was to cross-validate previously developed Actiwatch (AW; Ekblom et al. 2012) and AcitGraph (AG; Sirard et al. 2005; AG-P, Pate et al.

Psychosocial and Friend Influences on Objective Sedentary Behavior and Screen Time: A Mixed Methods Analysis.

Background: Sedentary behavior (SB) increases throughout adolescence, and is associated with adverse health outcomes.

Purpose: Examine psychosocial and friend influences on SB and screen time in adolescents using a mixed-methods design.

Methods: 108 middle and high school students wore accelerometers to measure objective SB, completed screen time and psychosocial questionnaires, and nominated friends to complete activity questionnaires.

Comparison of the Effects of Stable and Dynamic Furniture on Physical Activity and Learning in Children.

We compared the effects of traditional (stable) and non-traditional (dynamic) school furniture on children's physical activity (PA), energy expenditure (EE), information retention, and math skills. Participants were 12 students (8.3 years, 58 % boys) in grades 1-5.

Social and Psychological Factors Associated With Adolescent Physical Activity.

Objective: The purpose of this study was to examine, using structural equation modeling, the associations between nominated friend physical activity (PA), friend social support with individual PA-related psychological factors, and adolescent PA.

Methods: Data were obtained from EAT 2010 (Eating and Activity Among Teens), a large cross-sectional study conducted in 20 middle and high schools. The sample consisted of 1951 adolescents (mean age: 14.

The influence of friends and psychosocial factors on physical activity and screen time behavior in adolescents: a mixed-methods analysis.

(1) Determine the association between adolescent moderate-to-vigorous physical activity (MVPA) and screen time with their nominated friends' behaviors and (2) explore potential mechanisms of friends' social influences on MVPA and screen time. Participants consisted of 152 adolescents (mean age: 14.5 years, 53 % female, 50 % high school, 80 % Caucasian).

Validation of Accelerometer Thresholds and Inclinometry for Measurement of Sedentary Behavior in Young Adult University Students.

Sedentary behavior (SB) is a major contributor to obesity and significant morbidity and mortality in adolescence and adulthood, yet measurement of SB is still evolving. The purpose of this study was to assess the degree of construct validity of the inclinometer function and single-axis and vector magnitude accelerometry metrics of the ActiGraph GT3X+ in objectively measuring SB and physical activity in 28 young adult university students who performed nine semi-structured activities, each for five minutes: lying, sitting, reading, seated video gaming, video watching, seated conversation, standing, stationary biking, and treadmill walking. Inclinometry and four output metrics from the ActiGraph were analyzed in comparison to direct observation by a researcher recorded each minute.

Effect of a School Choice Policy Change on Active Commuting to Elementary School.

Purpose: The purposes of this study were to assess the effect of restricting school choice on changes in travel distance to school and transportation mode for elementary school students.

Design: Study design was pre-post (spring 2010-fall 2010) quasi-experimental.

Setting: Study setting was all public elementary schools in Minneapolis, Minnesota.

The relationship of area-level sociodemographic characteristics, household composition and individual-level socioeconomic status on walking behavior among adults.

Understanding the contextual factors associated with why adults walk is important for those interested in increasing walking as a mode of transportation and leisure. This paper investigates the relationships between neighborhood-level sociodemographic context, individual level sociodemographic characteristics and walking for leisure and transport. Data from two community-based studies of adults (n=550) were used to determine the association between the area-sociodemographic environment (ASDE), calculated from U.

Physical activity and screen time in adolescents and their friends.

Background: Little is known about the actual physical activity and screen time behaviors of an adolescent's friends relative to the individual's behavior.

Purpose: To determine the associations between an adolescent's physical activity and screen time and his/her nominated friends' physical activity and screen time.

Methods: Data were obtained from EAT 2010 (Eating and Activity Among Teens), a large cross-sectional study (n=2126) conducted in 20 middle schools and high schools in Minneapolis/St.

Examination of a telephone-based exercise intervention for the prevention of postpartum depression: design, methodology, and baseline data from The Healthy Mom study.

Research indicates that exercise is an efficacious intervention for depression among adults; however, little is known regarding its efficacy for preventing postpartum depression. The Healthy Mom study was a randomized controlled trial examining the efficacy of an exercise intervention for the prevention of postpartum depression. Specifically, postpartum women with a history of depression or a maternal family history of depression (n=130) were randomly assigned to a telephone-based exercise intervention or a wellness/support contact control condition each lasting six months.

Multilevel predictors of adolescent physical activity: a longitudinal analysis.

Background: To examine how factors from a social ecologic model predict physical activity (PA) among adolescents using a longitudinal analysis.

Methods: Participants in this longitudinal study were adolescents (ages 10-16 at baseline) and one parent enrolled in the Transdisciplinary Research on Energetics and Cancer-Identifying Determinants of Eating and Activity (TREC-IDEA) and the Etiology of Childhood Obesity (ECHO). Both studies were designed to assess a socio-ecologic model of adolescent obesity risk.