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. Methods: Four units of each activity tracker (Movband [MB], Sqord [SQ], and Zamzee [ZZ]) were tested in an orbital shaker for 5-minutes at three frequencies (1.3, 1.9, and 2.5 Hz). Participants for Phase 2 (N=14) and Phase 3 (N=16) were 6-12 year old children (50% male). For Phase 2, participants completed 9 structured activities while wearing each tracker, the ActiGraph GT3X+ (AG) research accelerometer, and a portable indirect calorimetry system to assess energy expenditure (EE). For Phase 3, participants wore all 4 devices for 4 consecutive days. Correlation coefficients, linear models, and non-parametric statistics evaluated the criterion and construct validity of the activity tracker output. Results: Output from all devices was significantly associated with oscillation frequency (r=.92-.99). During Phase 2, MB and ZZ only differentiated sedentary from light intensity (PPr=.76, .86, and .59 for the MB, SQ, and ZZ, respectively). Conclusions: Across study phases, the SQ demonstrated stronger validity than the MB and ZZ. The validity of youth-oriented activity trackers may directly impact their effectiveness as behavior modification tools, demonstrating a need for more research on such devices

Validity and reliability of a home environment inventory for physical activity and media equipment

<p>Abstract</p> <p>Background</p> <p>Little is known about how the home environmental supports physical activity and screen media usage. The purpose of this study was to develop and test the reliability and validity of a self-report instrument to comprehensively reflect the availability and accessibility of physical activity and screen media equipment in the home environment.</p> <p>Methods</p> <p>Ten families participated in the initial field testing to provide feedback for instrument development. Thirty one adult participants, each of whom had at least one child 10–17 years old, completed two Physical Activity and Media Inventory (PAMI) instruments. The first PAMI was completed simultaneously, but independently, with a research assistant to assess validity. A second PAMI was completed by the participant one week later to assess reliability.</p> <p>Results</p> <p>The adult participants were mostly mothers/female guardians, mean age 38 ± 7.2 years, mostly Caucasian (52%), college educated (65%), living in single family homes (74%). Test-retest reliability was acceptable to strong for all summary variables (physical activity equipment, ICC = 0.76 to 0.99; media equipment, ICC = 0.72 to 0.96). For validation, reports from participants and research assistants were strongly correlated (physical activity, 0.67 – 0.98; media, 0.79 – 0.96). Compared to participants, research assistants reported a greater percentage of physical activity equipment as "in plain view and easy to get to" and a smaller percentage of items as "put away and difficult to get to".</p> <p>Conclusion</p> <p>Our results indicate strong evidence for the reliability and validity of the variables calculated from the PAMI. This self report inventory may be useful in assessing the availability of physical activity and screen media equipment in the home environment and could be used in conjunction with other home assessment tools (food availability, parenting styles and feeding practices) to identify obesogenic home environments.</p

Multilevel predictors of adolescent physical activity: a longitudinal analysis

<p>Abstract</p> <p>Background</p> <p>To examine how factors from a social ecologic model predict physical activity (PA) among adolescents using a longitudinal analysis.</p> <p>Methods</p> <p>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. PA was collected using ActiGraph activity monitors at two time points 24 months apart. Other measures included objective height and weight, adolescent and parent questionnaires on multilevel psychological, behavioral and social determinants of PA, and a home PA equipment inventory. Analysis was conducted using SAS, including descriptive characteristics, bivariate and stepped multivariate mixed models, using baseline adjustment. Models were stratified by gender.</p> <p>Results</p> <p>There were 578 adolescents with complete data. Results suggest few statistically significant longitudinal associations with physical activity measured as minutes of MVPA or total counts from accelerometers. For boys, greater self-efficacy (B = 0.75, <it>p </it>= 0.01) and baseline MVPA (B = 0.55, <it>p </it>< 0.01) remained significantly associated with MVPA at follow-up. A similar pattern was observed for total counts. For girls, baseline MVPA (B = 0.58, <it>p </it>= 0.01) and barriers (B = -0.32, <it>p </it>= 0.05) significantly predicted MVPA at follow-up in the full model. The full multilevel model explained 30% of the variance in PA among boys and 24% among girls.</p> <p>Conclusions</p> <p>PA change in adolescents is a complex issue that is not easily understood. Our findings suggest early PA habits are the most important predictor of PA levels in adolescence. Intervention may be necessary prior to middle school to maintain PA through adolescence.</p

Adolescent physical activity and screen time: associations with the physical home environment

<p>Abstract</p> <p>Background</p> <p>Previous research on the environment and physical activity has mostly focused on macro-scale environments, such as the neighborhood environment. There has been a paucity of research on the role of micro-scale and proximal environments, such as that of the home which may be particularly relevant for younger adolescents who have more limited independence and mobility. The purpose of this study was to describe associations between the home environment and adolescent physical activity, sedentary time, and screen time.</p> <p>Methods</p> <p>A total of 613 parent-adolescent dyads were included in these analyses from two ongoing cohort studies. Parents completed a Physical Activity and Media Inventory (PAMI) of their home environment. Adolescent participants (49% male, 14.5 ± 1.8 years) self-reported their participation in screen time behaviors and wore an ActiGraph accelerometer for one week to assess active and sedentary time.</p> <p>Results</p> <p>After adjusting for possible confounders, physical activity equipment density in the home was positively associated with accelerometer-measured physical activity (p < 0.01) among both males and females. Most of the PAMI-derived measures of screen media equipment in the home were positively associated with adolescent female's screen time behavior (p ≤ 0.03). In addition, the ratio of activity to media equipment was positively associated with physical activity (p = 0.04) in both males and females and negatively associated with screen time behavior for females (p < 0.01).</p> <p>Conclusions</p> <p>The home environment was associated with physical activity and screen time behavior in adolescents and differential environmental effects for males and females were observed. Additional research is warranted to more comprehensively assess the home environment and to identify obesogenic typologies of families so that early identification of at-risk families can lead to more informed, targeted intervention efforts.</p

Race Differences in Activity, Fitness, and BMI in Female Eighth Graders Categorized by Sports Participation Status

The purpose of this study was to identify racial differences in physical activity (PA), fitness, and BMI in female 8th-grade sports participants and nonparticipants. Girls from 31 South Carolina middle schools (N=1,903, 48% White; mean age=13.6 ± 0.63) reported PA and previous year sports-team participation, completed a submaximal fitness test, and had height and weight measured. Sports team participation was positively associated with PA and negatively associated with television viewing and BMI, in a dose-response manner. Compared with Whites, African-Americans reported less PA and more television viewing, and had greater BMI scores. Whereas PA intervention programs that incorporate a sports-team component could benefit all girls, African-American girls could be specifically targeted because of their lower physical activity

The relative influence of demographic, individual, social, and environmental factors on physical activity among boys and girls

<p>Abstract</p> <p>Background</p> <p>This study aimed to evaluate the associations of selected demographic, individual, social, and environmental factors with moderate-to-vigorous physical activity (MVPA) in a sample of children and adolescents.</p> <p>Methods</p> <p>MVPA was assessed among youth (n = 294) 10-17-years-old using the ActiGraph accelerometer. Youth completed measures of demographic and individual variables related to physical activity (PA), perceived social support by parents and peers, and perceived neighborhood characteristics. Parents completed the long-form of the International Physical Activity Questionnaire. The Physical Activity and Media Inventory was used to measure the home environment and Geographical Information Systems software was used to measure the physical neighborhood environment. Bivariate correlations and hierarchical multiple regression were conducted stratified by gender.</p> <p>Results</p> <p>Boys participated in significantly more MVPA than girls. In hierarchical analyses, peer support, home PA equipment, and temperature were significantly associated with MVPA among boys whereas distance to the school they attended was associated with MVPA among girls. The final models accounted for 25% and 15% of the variance in MVPA among boys and girls, respectively.</p> <p>Conclusions</p> <p>Important differences exist among the individual, social, and environmental factors related to MVPA between boys and girls. Boys' levels of activity appear to be influenced by factors closely linked to unstructured and social types of activities whereas girls' activities relate to internal and external barriers as well as their proximity to their schools. The prospective contribution of these important individual, social, and environmental factors to changes in MVPA among children and adolescents remains to be determined.</p

Physical Activity and Screen Time in Adolescents and Their Nominated Friends

Background: The social transmission of obesity has been reported in adolescent social networks. However, the behavioral antecedents to obesity (physical activity [PA], screen time, and diet) are the factors that would actually be transmitted through these networks. To date, little is known about the social influences affecting an individual adolescent’s PA and screen time behaviors. Purpose: To determine the associations between an adolescent’s PA and screen time and his/her nominated friends’ PA and screen time. Methods: Data were obtained from EAT 2010 (Eating and Activity among Teens), a large cross-sectional study (n=2,126) conducted in 20 middle schools and high schools in Minneapolis/St. Paul, Minnesota, USA during the 2009-2010 academic year. Each participant (Ego) nominated up to six friends (Alters) from a school roster and data from those friends was also obtained as part of the school-based data collection procedures. PA and screen time were assessed with previously used and validated questionnaires. Generalized estimating equation models, stratified by gender, were used to assess associations between adolescents’ PA and screen time and their friends’ PA and screen time. Results: Females’ PA was associated with their male and female friends’ PA, including their female best friends (all p\u3c0.05). Males’ PA was associated with their female friends’ PA (p\u3c0.03). Females’ screen time was associated with their male and female friends’ screen time (p\u3c0.03), but not with their best friends. Males’ screen time was only associated with their female friends’ screen time (p=0.04). Conclusions: The associations between individual and friend PA and screen time, especially in females, indicate a need to consider these social relationships when investigating weight-related behaviors in adolescents. Longitudinal data using validated measures of PA and screen time, and analyzed using sophisticated modeling techniques are needed to better understand social influences on adolescent weight-related behaviors and inform future intervention efforts

The relative influence of demographic, individual, social, and environmental factors on physical activity among boys and girls

Background: This study aimed to evaluate the associations of selected demographic, individual, social, and environmental factors with moderate-to-vigorous physical activity (MVPA) in a sample of children and adolescents. Methods: MVPA was assessed among youth (n = 294) 10-17-years-old using the ActiGraph accelerometer. Youth completed measures of demographic and individual variables related to physical activity (PA), perceived social support by parents and peers, and perceived neighborhood characteristics. Parents completed the long-form of the International Physical Activity Questionnaire. The Physical Activity and Media Inventory was used to measure the home environment and Geographical Information Systems software was used to measure the physical neighborhood environment. Bivariate correlations and hierarchical multiple regression were conducted stratified by gender. Results: Boys participated in significantly more MVPA than girls. In hierarchical analyses, peer support, home PA equipment, and temperature were significantly associated with MVPA among boys whereas distance to the school they attended was associated with MVPA among girls. The final models accounted for 25% and 15% of the variance in MVPA among boys and girls, respectively. Conclusions: Important differences exist among the individual, social, and environmental factors related to MVPA between boys and girls. Boys\u27 levels of activity appear to be influenced by factors closely linked to unstructured and social types of activities whereas girls\u27 activities relate to internal and external barriers as well as their proximity to their schools. The prospective contribution of these important individual, social, and environmental factors to changes in MVPA among children and adolescents remains to be determined

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.S. Census variables, and individual-level SES as potential correlates of walking behavior. Descriptive statistics, mean comparisons and Pearson’s correlations coefficients were used to assess bivariate relationships. Generalized estimating equations were used to model the relationship between ASDE, as quartiles, and walking behavior. Adjusted models suggest adults engage in more minutes of walking for transportation and less walking for leisure in the most disadvantaged compared to the least disadvantaged neighborhoods but adding individual level demographics and SES eliminated the significant results. However, when models were stratified for free or reduced cost lunch, of those with children who qualified for free or reduced lunch, those who lived in the wealthiest neighborhoods engaged in 10.7 min less of total walking per day compared to those living in the most challenged neighborhoods (p < 0.001). Strategies to increase walking for transportation or leisure need to take account of individual level socioeconomic factors in addition to area-level measures

Impacts of active school design on schooltime 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\u27 school-time SB and PA. Methods Accelerometers measured SB and PA at pre and post time-points in an intervention group who moved to the new school (n = 21) and in a comparison group experiencing no school environmental change (n = 20). Difference-in-difference (DD) analysis examined SB and PA outcomes in these groups. Measures were also collected post-intervention from an independent, grade-matched group of students in the new school (n = 21). Results As expected, maturational increases in SB were observed. However, DD analysis estimated that the intervention attenuated increase in SB by 81.2 ± 11.4 minutes/day (p\u3c0.001), controlling for time in moderate to vigorous physical activity (MVPA). The intervention was also estimated to increase daily number of breaks from SB by 23.4 ± 2.6 (p \u3c .001) and to increase light physical activity (LPA) by 67.7 ± 10.7 minutes/day (p\u3c0.001). However, the intervention decreased MVPA by 10.3 ± 2.3 minutes/day (p\u3c0.001). Results of gradematched independent samples analysis were similar, with students in the new vs. old school spending 90.5 ± 16.1 fewer minutes/day in SB, taking 21.1 ± 2.7 more breaks from SB (p\u3c0.001), and spending 64.5 ± 14.8 more minutes in LPA (p\u3c0.001), controlling for time in MVPA. Students in the new school spent 13.1 ± 2.7 fewer minutes in MVPA (p\u3c0.001) than their counterparts in the old school. Conclusions This pilot study found that active school design had beneficial effects on SB and LPA, but not on MVPA. Mixed results point to a need for active classroom design strategies to mitigate SB, and quick access from classrooms to areas permissive of high-intensity activities to promote MVPA. Integrating active design with programs/policies to promote PA may yield greatest impact on PA of all intensities