Where can they play? Outdoor spaces and physical activity among adolescents in U.S. urbanized areas

ObjectiveTo estimate behavior-specific effects of several objectively measured outdoor spaces on different types of moderate to vigorous physical activity (MVPA) in a large, diverse sample of U.S. adolescents.MethodsUsing data from Wave I (1994–1995) of the National Longitudinal Study of Adolescent Health (U.S., n = 10,359) and a linked geographic information system, we calculated percent greenspace coverage and distance to the nearest neighborhood and major parks. Using sex-stratified multivariable logistic regression, we modeled reported participation in wheel-based activities, active sports, exercise, and ≥ 5 MVPA bouts/week as a function of each outdoor space variable, controlling for individual- and neighborhood-level sociodemographics.ResultsAvailability of major or neighborhood parks was associated with higher participation in active sports and, in females, wheel-based activity and reporting ≥ 5 MVPA bouts/week [OR (95% CI): up to 1.71 (1.29, 2.27)]. Greater greenspace coverage was associated with reporting ≥ 5 MVPA bouts/week in males and females [OR (95% CI): up to 1.62 (1.10, 2.39) for 10.1 to 20% versus ≤ 10% greenspace] and exercise participation in females [OR (95% CI): up to 1.73 (1.21, 2.49)].ConclusionsProvision of outdoor spaces may promote different types of physical activities, with potentially greater benefits in female adolescents, who have particularly low physical activity levels.     

Physical activity outcomes in afterschool programs: A group randomized controlled trial

IntroductionAfterschool programs (ASPs) across the US are working towards achieving the standard of all children accumulating 30 min of moderate-to-vigorous physical activity (MVPA) during program time. This study describes the two-year impact of an intervention designed to assist ASPs meeting the 30 min/day MVPA standard.MethodsUsing a two-year delayed treatment, group randomized controlled trial, 20 ASPs serving ~ 1700 children/year (6–12 yrs) were randomized to either an immediate (n = 10, baseline-2013 and 2 yrs intervention fall-2013-to-spring-2015) or delayed group (n = 10, baseline 2013–2014 and 1 yr intervention fall-2014-to-spring-2015). The intervention, Strategies-To-Enhance-Practice (STEPs), focused on programming MVPA in the daily schedule, training of staff and leaders, and ongoing technical support/assistance. Accelerometry-derived proportion of children meeting the 30 min/day MVPA standard was measured in the spring of each year. Mixed model logistic regressions were used to examine the change in the odds of achieving the MVPA standard. Analyses were conducted in 2015. Data were collected in one southeastern US state.ResultsImmediate boys (n = 677) and delayed girls (n = 658) increased the percent achieving 30 min MVPA/day from 35.9% to 47.0% (odds ratio [OR] = 1.88, 95% CI 1.18–3.00) and 13.1% to 19.1% (OR = 1.42, 95% CI 1.03–1.96). Immediate girls (n = 613) and delayed boys (n = 687) exhibited a nonsignificant increase from 19.1% to 21.6% (OR = 1.20, 95% CI 0.84–1.72) and 29.0% to 31.3% (OR = 1.13, 95%CI 0.80–1.58).ConclusionsSTEPs can have an impact on children's MVPA and time spent sedentary, yet was unable to fully achieve the goal of all children accumulating 30 min MVPA/day. Additional efforts are need to identify strategies ASPs can use to meet this important public health standard.     

Spatial analysis of crime incidence and adolescent physical activity

ObjectivesAdolescents do not achieve recommended levels of physical activity. Crime is believed to be a barrier to physical activity among youth, but findings are inconsistent. This study compares the spatial distribution of crime incidences and moderate-to-vigorous physical activity (MVPA) among adolescents in Massachusetts between 2011 and 2012, and examines the correlation between crime and MVPA.MethodsEighty adolescents provided objective physical activity (accelerometer) and location (Global Positioning Systems) data. Crime report data were obtained from the city police department. Data were mapped using geographic information systems, and crime and MVPA densities were calculated using kernel density estimations. Spearman's correlation tested for associations between crime and MVPA.ResultsOverall, 1694 reported crimes and 16,702 min of MVPA were included in analyses. A strong positive correlation was present between crime and adolescent MVPA (ρ = 0.72, p < 0.0001). Crime remained positively associated with MVPA in locations falling within the lowest quartile (ρ = 0.43, p < 0.0001) and highest quartile (ρ = 0.32, p < 0.0001) of crime density.ConclusionsThis study found a strong positive association between crime and adolescent MVPA, despite research suggesting the opposite relationship. This counterintuitive finding may be explained by the logic of a common destination: neighborhood spaces which are desirable destinations and promote physical activity may likewise attract crime.     

Daily movement patterns and biological markers among adults in the United States

ObjectiveTo examine the combined effects of sedentary (SED), light (LPA) and moderate-to-vigorous physical activity (MVPA) on biological markers among a nationally representative sample of U.S. adults.MethodsData from the 2003–2006 NHANES study was used, with 5580 adults (≥ 20 years) included in the study. Participants wore an ActiGraph 7164 accelerometer with accelerometry data used to create four movement pattern groups: ≥ 150 min/week of MVPA and LPA ≥ SED; ≥ 150 min/week of MVPA and LPA < SED; < 150 min/week of MVPA but LPA ≥ SED; and < 150 min/week of MVPA and LPA < SED. Blood samples were taken to assess various biological parameters (e.g., cholesterol).Results47.2% (SE: 1.2) of Americans engaged in < 150 min/week of MVPA and had a negative LPA–SED balance. In general, participants who engaged in ≥ 150 min/week of MVPA, regardless of LPA–SED balance, had more favorable biological levels; however, there was evidence showing that even if individuals engaged in < 150 min/week of MVPA, but if their LPA exceeded SED, they had more favorable levels of triglycerides and insulin.ConclusionsPrograms are needed to increase American's engagement in MVPA, and also ensure that LPA exceeds SED behavior.     

Safety in numbers: Does perceived safety mediate associations between the neighborhood social environment and physical activity among women living in disadvantaged neighborhoods?

ObjectiveThe aim of this study is to examine associations between the neighborhood social environment and leisure-time physical activity (LTPA)¹ and walking among women, and whether these associations are mediated by perceived personal safety.MethodsWomen (n = 3784) living in disadvantaged urban and rural neighborhoods within Victoria, Australia completed a self-administered survey on five social environment variables (neighborhood crime, neighborhood violence, seeing others walking and exercising in the neighborhood, social trust/cohesion), perceived personal safety, and their physical activity in 2007/8. Linear regression analyses examined associations between social environment variables and LTPA and walking. Potential mediating pathways were assessed using the product-of-coefficients test. Moderated mediation by urban/rural residence was examined.ResultsEach social environment variable was positively associated with engaging in at least 150 min/week of LTPA (OR = 1.16 to 1.56). Only two social environment variables, seeing others walking (OR = 1.45) and exercising (OR = 1.31), were associated with ≥ 150 min/week of walking. Perceived personal safety mediated all associations. Stronger mediation was found in urban areas for crime, violence and social trust/cohesion.ConclusionThe neighborhood social environment is an important influence on physical activity among women living in disadvantaged areas. Feelings of personal safety should not be included in composite or aggregate scores relating to the social environment.     

Empowering adolescents to be physically active: Three-year results of the Sigue la Huella intervention

ObjectiveTo examine the effects of a school-based intervention called Sigue la Huella (Follow the Footstep) on adolescents' daily moderate-to-vigorous physical activity (MVPA).MethodThis quasi-experimental, cohort study took place in four secondary schools in Huesca (Spain) during the 2009–2010, 2010–2011, and 2011–2012 academic years (students aged 12–15 years). Two schools were assigned to the experimental condition (n = 368) and two schools to the control condition (n = 314). Sigue la Huella was based on the social ecological model and self-determination theory. MVPA was measured for 7 days on 4 occasions using accelerometers. Data were analyzed with individual growth curve models.ResultsThere was a significant difference in linear growth rate of daily MVPA between the experimental and the control group, independent of study wave, type of school (public vs. private), grade level and gender (p < 0.001). Specifically, MVPA increased in the experimental group (β = 7.02, 95% confidence interval (CI) = 1.27 to 12.78, p = 0.017) and tended to decrease in the control group (β = − 5.26, 95% CI = − 11.17 to 0.65, p < 0.081). The observed increase was larger in boys than in girls (p = 0.003).ConclusionsSigue la Huella had a positive effect on adolescents' daily MVPA over three school years. Both genders benefited from the intervention, although boys to a greater extent.     

Neighborhood walkability and health outcomes among older adults: The mediating role of physical activity

We examined the mediating role of physical activity on the relationships of walkability with Flemish older adults' health outcomes. In low income neighborhoods, residents of high walkable neighborhoods had a 1.5 kg/m² lower BMI than low walkable residents. Of this difference 0.3 kg/m² (19%) and 0.2 kg/m² (12%) were explained through walking for transport and MVPA, respectively. Similar findings were observed for waist circumference. Walkability did not relate to functional performance or quality of life. Walkable neighborhoods may benefit older adults’ health, especially in low income neighborhoods. More research in other contexts is warranted to confirm current findings.     

Joint effects of objectively-measured sedentary time and physical activity on all-cause mortality

ObjectiveExamine the joint effects of objectively-measured sedentary time and moderate-to-vigorous physical activity (MVPA) on all-cause mortality.MethodsThe present study included data from the 2003–2006 National Health & Nutrition Examination Survey, with mortality follow-up data (via National Death Index) through 2011 (N = 5575 U.S. adults). Sedentary time (activity counts/min between 0 and 99) and MVPA (activity counts/min ≥ 2020) were objectively measured using the ActiGraph 7164 accelerometer.ResultsThe median age of the participants was 50 yrs; proportion of men was 50.2%; proportion of whites was 53.8%, 18.7% for blacks; median follow-up was 81 months; and 511 deaths occurred over the follow-up period. After adjusting for age, gender, race-ethnicity, cotinine, weight status, poverty level, C-reactive protein and comorbid illness (summed score of 0–8 chronic diseases), and for a 1 min increase in MVPA and sedentary time, both MVPA (HR_adjusted = 0.98; 95% CI: 0.96–0.99; P = 0.04) and sedentary time (HR_adjusted = 1.001; 95% CI: 1.0003–1.002; P = 0.008) were independently associated with all-cause mortality. Further, MVPA was associated with all-cause mortality among those with greater (above median) sedentary time (HR_adjusted = 0.95; 95% CI: 0.93–0.97; P < .001). Sedentary time was not associated with all-cause mortality among those engaging in above median levels of MVPA (HR_adjusted = 0.998; 95% CI: 0.996–1.001; P = .32), but sedentary time was associated with increased mortality risk among those below median levels of MVPA (HR = 1.002; 95% CI: 1.001–1.003; P < 0.001).ConclusionsSedentary time and MVPA are independently associated with all-cause mortality. Above median sedentary time levels did not negate the beneficial effects of MVPA on all-cause mortality risk.     

Symptoms of specific anxiety disorders may relate differentially to different physical activity modalities in young adults

BackgroundAnxiety symptoms may be a barrier to physical activity (PA) such that persons who experience anxiety engage in less PA. The purpose of this study was to assess if symptoms of panic disorder, social phobia, generalized anxiety disorder (GAD) or agoraphobia are associated with frequency, intensity or type of PA in young adults.MethodsData on lifetime anxiety symptoms and current PA levels were collected in self-report questionnaires in 2007–2008 from 880 persons aged 18–24 years participating in the Nicotine Dependence in Teens (NDIT) study. The associations between anxiety symptom subtypes and different PA modalities were investigated in five multivariable logistic regression models, one for each of five PA indicators (i.e., meeting moderate-to vigorous PA (MVPA) guidelines, meeting strength training guidelines, meeting both MVPA and strength training guidelines, participating in team sports, frequent walking) as outcomes.Results37%, 47%, 40% and 21% of participants reported lifetime symptoms of panic disorder, social phobia, GAD, and agoraphobia, respectively. In multivariable logistic regression, participants who endorsed lifetime GAD symptoms were statistically significantly less likely to meet MVPA guidelines (OR 0.5, 95% CI 0.4–0.8, p < 0.05), and MVPA and strength training guidelines (OR 0.7, 95% CI 0.5–1.0, p < 0.05). Those with agoraphobia symptoms were more likely to walk frequently [OR (95% CI) = 1.6 (1.1, 2.3)].ConclusionPA interventions may need to be tailored to people who have experienced specific anxiety symptoms to maximize adherence to PA recommendations, and increase the potential for health benefits from PA participation.     

Implementing classroom physical activity breaks: Associations with student physical activity and classroom behavior

ObjectiveTo investigate the relation of classroom physical activity breaks to students' physical activity and classroom behavior.MethodsSix elementary-school districts in California implemented classroom physical activity interventions in 2013–2014. Students' (N = 1322) accelerometer-measured moderate-to-vigorous physical activity (MVPA) during school and teachers' (N = 397) reports of implementation and classroom behavior were assessed in 24 schools at two time points (both post-intervention). Mixed-effects models accounted for nested data.ResultsMinutes/day of activity breaks was positively associated with students' MVPA (βs = .07–.14; ps = .012–.016). Students in classrooms with activity breaks were more likely to obtain 30 min/day of MVPA during school (OR = 1.75; p = .002). Implementation was negatively associated with students having a lack of effort in class (β = − .17; p = .042), and student MVPA was negatively associated with students being off task or inattentive in the classroom (β = − .17; p = .042). Students provided with 3–4 physical activity opportunities (classroom breaks, recess, PE, dedicated PE teacher) had ≈ 5 more min/day of school MVPA than students with no opportunities (B = 1.53 min/opportunity; p = .002).ConclusionsImplementing classroom physical activity breaks can improve student physical activity during school and behavior in the classroom. Comprehensive school physical activity programs that include classroom-based activity are likely needed to meet the 30 min/day school physical activity guideline.     

The association between discrepant weight perceptions and objectively measured physical activity

BackgroundSome individuals perceive themselves as being normal weight, despite having an excess body fat percentage (e.g., underestimate weight). Conversely, other individuals perceive themselves as being overweight, despite having a normal body fat percentage (e.g., overestimate weight). When perceived and actual weight statuses are incongruent, individuals possess a discrepant weight perception. The association between discrepant weight perceptions and engagement in moderate-to-vigorous physical activity (MVPA) has not been thoroughly investigated, which was this study's purpose.MethodsFor this cross-sectional study, data from the 2003–2006 National Health and Nutrition Examination Survey were utilized (N = 5462 adults). MVPA was assessed via accelerometry. Based on measured body mass index and whether participants considered themselves as overweight, underweight, or about the right weight, we classified individuals as accurate perception, overestimate weight (discrepant), or underestimate weight (discrepant). A negative binomial logistical regression was used to assess the association between discrepant weight perception (independent variable) and engagement in MVPA (outcome variable).ResultsFemales who said that they are normal weight, but were in fact overweight based on body mass index, engaged in 13% less MVPA (rate ratio = .87, 95% confidence interval: .769–.999, P = .05). Also, older adults (> 60 yrs) who said that they are normal weight, but were overweight based on body mass index, engaged in 23% less MVPA (rate ratio = .77, 95% confidence interval: .616–.965, P = .025).ConclusionDiscrepant weight perceptions were associated with less objectively measured MVPA. Interventions should take weight perceptions into consideration when designing and evaluating intervention impact.     

Walking trips to parks: Exploring demographic,environmental factors,and preferences for adults with children in the household

Objectives(1) To understand demographic and environmental factors influencing walking trips to parks for adults with children living at home; and (2) To determine if preferences for walking environments may influence walking trips and why.MethodsNeighborhoods with varying levels of canopy coverage and access to destinations were selected within the city of Seattle, Washington and surrounding suburbs. Walking trip frequency, preferences for walking environments, and demographic information were measured through a postal survey in fall 2006 (21% response rate, N = 617; 41% adults with children living in the household, n = 250). Analysis of variance and multiple linear regressions were used to test the associations between variables. Chi-square and qualitative content analysis were used to understand preferences for walking environments.ResultsAdult respondents with children living at home walked most frequently to parks compared to other destinations. Owning a dog, living within close proximity to a variety of destinations, perceptions of ample neighborhood vegetation, and preference for natural-looking environments were factors positively associated with these walking trips.ConclusionsDemographic and environmental factors influence walking trips, particularly perceived level of neighborhood vegetation and individual preferences. However, highly vegetated walking environments also elicited concerns about safety for some respondents.     

Daily movement patterns and predicted 10-yr risk for a first atherosclerotic cardiovascular disease (ASCVD) event using the pooled cohort risk equations among US adults

ObjectiveExamine the association between movement patterns and predicted risk of a first atherosclerotic cardiovascular disease (ASCVD) event.MethodsData from the 2003–2006 National Health and Nutrition Examination Survey (NHANES) were used (40–79 yrs; N = 2421). Participants wore an ActiGraph 7164 accelerometer to create four movement pattern groups; Group 1: ≥ 150 min/wk of moderate-to-vigorous physical activity (MVPA) and light-intensity physical activity (LIPA) ≥ sedentary behavior (SB); Group 2: ≥ 150 min/wk of MVPA and LIPA < SB; Group 3: < 150 min/wk of MVPA and LIPA ≥ SED; and Group 4: < 150 min/wk of MVPA and LIPA < SB. 10-yr risk for a first ASCVD event was estimated using the pooled cohort equations.ResultsAfter adjusting for age, gender, race–ethnicity and obesity, Group 2 (β = − 0.28; p = 0.44) was not significantly different than Group 1, but Groups 3 (β = 1.09; p = 0.01) and 4 (β = 1.44; p < 0.001) had a higher pooled risk score.ConclusionsThose in the least desirable movement pattern (Group 4) had the highest pooled risk score. Given the similar risk scores for Groups 1 and 2, future research is needed to determine if sufficient MVPA can counteract the potential consequences associated with an imbalanced LIPA:SB ratio (i.e., LIPA < SB).     

Physically active vs. sedentary academic lessons: A dose response study for elementary student time on task

BackgroundPhysically active academic lessons are an effective intervention to reduce sedentary time and increase student physical activity. They have also been shown to enhance task engagement, as indicated by observations of attention and behavior control, time on task (TOT). However, it is not clear if the improved TOT stems from the physical activity or if it is the result of an enjoyable break from traditional instruction. If it is due to physical activity, what dose of intensity is required for the effect? This study was designed to test these questions.MethodsParticipants were 320 children (7–9 years) recruited from school districts in Central Texas in 2012. They were assigned by classroom (n = 20) to one of four conditions: 1) sedentary, standard lesson (n = 72); 2) sedentary academic game (n = 87); 3) low to moderate intensity PA (LMPA), academic game (n = 81); and 4) moderate to vigorous intensity PA (MVPA), academic game (n = 76). Measures included PA via accelerometer and TOT.ResultsMixed-method RMANOVA indicated TOT decreased following the standard lesson (p < 0.001), showed no change following the sedentary academic game (p = 0.68), and increased following the LMPA (p < 0.01) and MVPA (p < 0.001) academic games.ConclusionsWhile the sedentary, academic game prevented the reduction in TOT observed in the standard lesson, PA resulted in increased TOT. Future research should be designed to examine the potential academic benefits of the change in TOT.     

Results of a randomized controlled trial to promote physical activity behaviours in mothers with young children

ObjectiveIncreasing levels of physical activity in mothers have long-term health benefits for the mother and family. The study aimed to evaluate the effect of a six-month, physical activity RCT for mothers of young children.MethodsWomen were recruited via playgroups and randomly assigned to intervention (n = 394) or control group (n = 322). The intervention group received a six-month multi-strategy programme delivered via playgroups in Perth, Australia. measures were mean minutes per week of moderate (M) and vigorous (V) intensity physical activity (PA), and number of days/week of muscle strength exercises.ResultsThe intervention had a significant effect on mean time for vigorous (p = 0.008), moderate (p = 0.023) and total physical activity (p = 0.001) when compared to the control group. The intervention group increased their vigorous activity by a mean of 24 min/week, moderate activity by 23 min/week and total physical activity by 72 min/week.ConclusionsA relatively minimum home based intervention was able to demonstrate modest but statistically significant improvements in physical activity in a hard to reach group. These changes if maintained over a longer period are likely to improve the health of mothers and have a positive impact on their partners and children. Australian and New Zealand Clinical Trials Registry ACTRN12609000735257.     

Longitudinal associations with changes in outdoor recreation area use for physical activity during a community-based intervention

Outdoor recreation areas (ORA) are important resources for physical activity (PA) and health promotion. While past research has identified correlates of ORA use, few studies have examined predictors of longitudinal changes in park- and trail-based PA in community settings.Using data from a 6-month community-based walking intervention study, we examined cross-sectional and longitudinal predictors of PA in ORAs. Data were collected from baseline and 6-month assessments from participants (n = 295) in a group walking intervention in South Carolina; participants enrolled from January 2012-May 2013. A decomposition scheme was used to examine the cross-sectional and longitudinal predictors of average group ORA use for PA, including social support, self-efficacy for PA, perceptions of neighborhood environment, and accelerometer-based PA, adjusting for gender. On average, participants were 49.4 + 13.3 years old, 66.1% were Black, and the majority were women. There was a mean increase in group ORA use of 2.1 + 0.4 days/month from baseline to 6 months. Cross-sectionally, higher levels of the percentage of time in MVPA, self-efficacy, and social support were associated with greater group-average ORA use. Longitudinally, increased social support from friends and rating of lighter motorized traffic were associated with increased group ORA use. Additionally, longitudinal increases in percentage of MVPA and more favorable rating of the neighborhood as a place to walk were both associated with decreased group ORA use. Better understanding how social and physical environmental characteristics impact ORA use for PA can lead to more effective intervention strategies and warrants greater attention in future research and public health promotion efforts.     

Objectively measured sedentary time and associations with insulin sensitivity: Importance of reallocating sedentary time to physical activity

ObjectiveThe aim of this study is to quantify associations between objectively measured sedentary time and markers of insulin sensitivity by considering allocation into light-intensity physical activity or moderate- to vigorous-intensity physical activity (MVPA).MethodsParticipants with an increased risk of impaired glucose regulation (IGR) were recruited (Leicestershire, United Kingdom, 2010–2011). Sedentary, light-intensity physical activity and MVPA time were measured using accelerometers. Fasting and 2-hour post-challenge insulin and glucose were assessed; insulin sensitivity was calculated by HOMA-IS and Matsuda-ISI. Isotemporal substitution regression models were used. Data were analysed in 2014.Results508 participants were included (average age = 65 years, female = 34%). Reallocating 30 min of sedentary time into light-intensity physical activity was associated a 5% (95% CI 1, 9%; p = 0.024) difference in Matsuda-ISI after adjustment for measured confounding variables. Reallocation into MVPA was associated with a 15% (7, 25%; p < 0.001) difference in HOMA-IS and 18% (8, 28%; p < 0.001) difference in Matsuda-ISI. Results for light-intensity physical activity were modified by IGR status with stronger associations seen in those with IGR.ConclusionsReallocating sedentary time into light-intensity physical activity or MVPA was associated with differences in insulin sensitivity, with stronger and more consistent associations seen for MVPA.     

Accelerometer steps/day translation of moderate-to-vigorous activity

Physical activity (PA) guidelines are typically communicated in terms of duration, frequency and intensity, e.g., 30 min/day of moderate-to-vigorous physical activity (MVPA) on at least 5 days/week. Step counters can be used to collect objective PA expressed as steps/day, however the association between steps/day and recommended PA levels is unclear.ObjectiveWe determined a direct steps/day translation of 30 min/day accumulated MVPA, using concurrently detected ActiGraph accelerometer-defined step and activity count data collected as part of the 2005–2006 National Health and Nutrition Examination Survey (NHANES).MethodWe employed statistical models to analyze data from 3523 participants 20+ years of age who wore the accelerometer for at least one valid day (i.e., at least 10/24 h) over 7 days.Results30 min/day of MVPA translated to approximately 7900 steps/day for males and 8300 steps/day for females. In a subsample of participants (n = 1197) with valid data on all 7 days, we found 150 min/week of MVPA translated to approximately 7000 steps/day (or 49,000 steps/week).ConclusionAccumulating approximately 8000 steps/day is a good proxy for 30 min of daily MVPA, while accumulating 7000 steps/day every day of the week is consistent with obtaining 150 min of weekly MVPA.     

Developmental trajectories of physical activity during elementary school physical education

ObjectivePhysical education (PE) during school provides an opportunity for children to be physically active. Few empirical studies have investigated developmental trajectories and determinants of objective moderate to vigorous physical activity (MVPA) during PE classes. The purpose of this study was to examine the developmental trajectories and determinants of MVPA during PE lessons in young children (8–12 years of age) in primary schools.MethodsStudents in grades 5–7 (n = 1202; 51.2% girls) were recruited from 17 elementary schools from the Geneva canton in 2012–2013. The percentage of time spent in accelerometer-assessed MVPA during regular PE lessons was used as a dependent variable.ResultsLinear mixed-model analyses revealed (a) that boys had a higher percentage of MVPA than girls, but none of the children reached the recommended activity levels (i.e., 50% of the PE class time spent in MVPA), (b) a linear decrease in the percentage of MVPA with age, (c) that higher perceived competence predicted a higher percentage of MVPA, and (d) that higher perceived competence reduced the negative linear effect of age among boys, but not among girls.ConclusionThe percentage of PE time spent in MVPA did not reach recommendations made by Centers for Disease Control and Prevention and decreased from 8 to 12 years old both for boys and girls. Perceived competence appears crucial to reduce MVPA decline for boys, but not for girls.     

Longitudinal associations of active commuting with body mass index

ObjectiveTo investigate the longitudinal associations between active commuting (walking and cycling to work) and body mass index (BMI).MethodWe used self-reported data on height, weight and active commuting from the Commuting and Health in Cambridge study (2009 to 2012; n = 809). We used linear regression to test the associations between: a) maintenance of active commuting over one year and BMI at the end of that year; and b) change in weekly time spent in active commuting and change in BMI over one year.ResultsAfter adjusting for sociodemographic variables, other physical activity, physical wellbeing and maintenance of walking, those who maintained cycle commuting reported a lower BMI on average at one year follow-up (1.14 kg/m², 95% CI: 0.30 to 1.98, n = 579) than those who never cycled to work. No significant association remained after adjustment for baseline BMI. No significant associations were observed for maintenance of walking. An increase in walking was associated with a reduction in BMI (0.32 kg/m², 95% CI: 0.03 to 0.62, n = 651, after adjustment for co-variates and baseline BMI) only when restricting the analysis to those who did not move. No other significant associations between changes in weekly time spent walking or cycling on the commute and changes in BMI were observed.ConclusionsThis work provides further evidence of the contribution of active commuting, particularly cycling, to preventing weight gain or facilitating weight loss. The findings may be valuable for employees choosing how to commute and engaging employers in the promotion of active travel.