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.     

Investigating links between moderate-to-vigorous physical activity and cognitive performance in elementary school students

BackgroundResearch has noted both physical and psychological benefits when children participate in physical activity. Recent studies indicate there may also be academic benefits and students may be more efficient learners after physical activity. This study investigated the influence of moderate-to-vigorous physical activity (MVPA) on four cognitive processes: planning, attention, simultaneous processing, and successive processing.MethodsParticipants were two classes of fourth-grade students in Ontario (n = 40). Using a counterbalanced design, students in the two classes completed standardized tests for each cognitive process both after no physical activity and following it (20 min MVPA within a 45 min lesson).ResultsThe results indicate that performance on the planning test significantly improved after physical activity (p < 0.001), controlling for sequence and habituation/retesting effects. No improvement was observed for attention, simultaneous processing, or successive processing.ConclusionPlanning is associated with problem solving skills and behaviour self-regulation. These skills may be improved in elementary school students immediately following physical activity.     

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.     

Effects of physical activity on schoolchildren's academic performance: The Active Smarter Kids (ASK) cluster-randomized controlled trial

ObjectiveTo investigate the effect of a seven-month, school-based cluster-randomized controlled trial on academic performance in 10-year-old children.MethodsIn total, 1129 fifth-grade children from 57 elementary schools in Sogn og Fjordane County, Norway, were cluster-randomized by school either to the intervention group or to the control group. The children in the 28 intervention schools participated in a physical activity intervention between November 2014 and June 2015 consisting of three components: 1) 90 min/week of physically active educational lessons mainly carried out in the school playground; 2) 5 min/day of physical activity breaks during classroom lessons; 3) 10 min/day physical activity homework. Academic performance in numeracy, reading and English was measured using standardized Norwegian national tests. Physical activity was measured objectively by accelerometry.ResultsWe found no effect of the intervention on academic performance in primary analyses (standardized difference 0.01–0.06, p > 0.358). Subgroup analyses, however, revealed a favorable intervention effect for those who performed the poorest at baseline (lowest tertile) for numeracy (p = 0.005 for the subgroup 1 group interaction), compared to controls (standardized difference 0.62, 95% CI 0.19–1.07).ConclusionsThis large, rigorously conducted cluster RCT in 10-year-old children supports the notion that there is still inadequate evidence to conclude that increased physical activity in school enhances academic achievement in all children. Still, combining physical activity and learning seems a viable model to stimulate learning in those academically weakest schoolchildren.     

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.     

Objectively assessed physical activity,fitness and subjective wellbeing

BackgroundThe existing evidence for a cross-sectional association between physical activity and subjective wellbeing is inconsistent, mainly because of the reliance on self reported physical activity, which might have conceptual overlap with subjective health.PurposeTo examine associations of objectively assessed physical activity and cardiorespiratory fitness with subjective wellbeing.MethodsA sub-sample of participants (921 men and women, mean age 44.6 ± 15.0 yrs, 46.4% men) from the 2008 Health Survey for England completed objective measures of physical activity (Actigraph) and an 8 min sub-maximal step test to estimate levels of cardiorespiratory fitness. The General Health Questionnaire and self-rated health was used as indicators of subjective wellbeing.ResultsThe recorded levels of moderate to vigorous physical activity (MVPA) were higher in participants reporting very good health (adjusted mean difference = 6.7, 95% CI, 1.1–12.4 min/d, p = 0.019) compared with participants reporting fair–poor health after adjustment for various confounders and fitness level. Neither physical fitness, objectively assessed sedentary time or light activity was related to self-rated health. There was also no association between objectively measured physical activity and fitness with psychological health, despite a robust association with self reported MVPA in the overall sample.ConclusionsObjectively assessed MVPA is independently associated with self-rated health. Self reported, but not objectively assessed MVPA, was associated with psychological health. The null findings with regards to psychological health might partly reflect selection biases associated with the healthy nature of this sub-sample of participants.     

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.     

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.     

Prospective effects of pedometer use and class competitions on physical activity in youth: A cluster-randomized controlled trial

ObjectiveTo evaluate the immediate effects of a school-based multi-component program to foster a physically active lifestyle in adolescence.Design/participantsIn a cluster-randomized controlled trial with pre- and post-assessment in 2014, 29 schools with 1162 8th grade students (48% girls) from Germany were included. Age ranged from 12 to 17 years (M = 13.74; SD = 0.67).InterventionWhile the control group attended education as usual, students in the intervention group received pedometers and took part in a class competition over a time period of 12 weeks. Classes with the most steps and best creative ideas to promote physical activity in everyday life were awarded.Main outcome measuresPrimary outcomes included out-of-school sports activities (h/week), moderate to vigorous physical activity (days/week with a minimum of 60 min), active commuting (min/day), doing chores (min/day), and sedentary behavior (h/day) assessed through self-administered questionnaires as well as cardiorespiratory fitness measured using the 20-m shuttle-run test (completed laps).ResultsSignificant interaction terms between group and wave of assessment were found on out-of-school sports activities (b = − 1.09 [− 1.89; − 0.29], p = 0.008), moderate to vigorous physical activity (b = − 0.29 [− 0.47; − 0.10], p = 0.002), and active commuting (b = − 20.41 [− 32.32; − 8.49], p = 0.001): students in the intervention group showed a higher increase of physical activity levels than students in the control group. The intervention effect on cardiorespiratory fitness missed significance marginally (b = − 1.52 [− 3.14; 0.98], p = 0.065), There was no effect on students' sedentary behavior (b = 0.06 [− 0.72; 0.84], p = 0.881).ConclusionsAn easy to administer school-based physical activity program (12 weeks) may enhance students' leisure-time physical activity.Trial registration number: ISRCTN49482118     

The school effect on children's school time physical activity: The PEACH Project

ObjectiveThe school-setting is a potentially important environment for influencing children's physical activity. However limited research has focused on whether children's school-time physical activity is associated with the school they attend. This paper investigates the school effect on children's physical activity.MethodParticipants were 1307 pupils aged 10–11 years recruited from 23 primary schools in Bristol, UK during 2006–2008. Multilevel modelling (MLM) (MLwin 2.02) was used to asses between school differences in children's physical activity, measured using accelerometry (ActiGraph GT1M), adjusting for both individual and school variables.ResultsA significant school effect (p = 0.001) was found accounting for 14.5% of the total variance in physical activity. Boys were significantly more active than girls (p < 0.001), and the school attended accounted for a greater proportion of variance in boys' physical activity than girls' (23.4% vs. 12.2%). Seasonal variation and economic deprivation of the school neighbourhood were both significantly associated with children's school-time activity.ConclusionThis paper highlights a significant school effect on children's physical activity providing evidence that the school attended should be accounted for in future analysis and supporting the use of MLM in this field. Further investigation is required to explain the differences in physical activity found between schools.     

The effects of shift work on free-living physical activity and sedentary behavior

ObjectiveAlthough occupation may influence physical activity and shift work schedule may influence cardiovascular disease risk factors, our understanding of the effects of shift work schedule on overall physical activity behavior and sedentary behavior is limited.MethodsData from the 2005–2006 National Health and Nutrition Examination Survey were used. Shift work schedule was defined as regular daytime shift, evening, night, rotating or another schedule. Physical activity and sedentary behavior were assessed via accelerometry. 1536 adult participants (≥ 20 years) indicated they currently work and provided data on all study variables.ResultsAfter adjustments, and compared to adults working a regular daytime shift, those working an evening (RR = 0.41, p = 0.001) and night (RR = 0.30, p = 0.001) shift, respectively, engaged in 59% and 70% less sustained (bouts) moderate-to-vigorous physical activity, but no differences occurred for overall moderate-to-vigorous physical activity. After adjustments, and compared to those working a regular daytime shift, those working a rotating shift engaged in more light-intensity physical activity (overall: β = 26.3 min/day; p = 0.03; bouts: β = 37.5, p = 0.01) and less sedentary behavior (β = − 28.5 min/day, p = 0.01).ConclusionsShift work schedule differentially influences physical activity and sedentary behavior. Physical activity and sedentary intervention strategies may need to be tailored based on shift work schedule.     

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.     

Prevalence of physical activity in European adults — Compliance with the World Health Organization's physical activity guidelines

BackgroundAdults are recommended to engage in at least 150 min/week of moderate-to-vigorous physical activity (PA).PurposeThis study aimed to examine the level of compliance with PA recommendations among European adults.MethodsUsing data from European Social Survey round 6, PA self-report data was collected from 52,936 European adults from 29 countries in 2012. Meeting PA guidelines was assessed using World Health Organization criteria.Results61.47% (60.77% male, 62.05% female) of European adults reported to be engaged in moderate to vigorous PA at least 30 min on 5 or more days per week. The likelihood of achieving the PA recommended levels was higher among respondents older than 18–24. For those aged 45–64 years the likelihood increased 65% (OR = 1.65, 95% CI: 1.51–1.82, p < 0.001) and 112% (OR = 2.12, 95% CI: 1.94–2.32, p < 0.001) for males and females, respectively. Those who were high school graduates were more likely to report achieving the recommended PA levels than those with less than high school education (males: OR = 1.19, 95% CI: 1.12–1.27, p < 0.001; females: OR = 1.13, 95% CI: 1.06–1.20, p < 0.001).ConclusionAlthough about 60% of European adults reported achieving the recommended levels of PA, there is much room for improvement among European adults, particularly among relatively inactive subgroups.     

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).     

Establishing school day pedometer step count cut-points using ROC curves in low-income children

Previous research has not established pedometer step count cut-points that discriminate children that meet school day physical activity recommendations using a tri-axial ActiGraph accelerometer criterion. The purpose of this study was to determine step count cut-points that associate with 30 min of school day moderate-to-vigorous physical activity (MVPA) in school-aged children. Participants included 1053 school-aged children (mean age = 8.4 ± 1.8 years) recruited from three low-income schools from the state of Utah in the U.S. Physical activity was assessed using Yamax DigiWalker CW600 pedometers and ActiGraph wGT3X-BT triaxial accelerometers that were concurrently worn during school hours. Data were collected at each school during the 2014–2015 school year. Receiver operating characteristic (ROC) curves were used to determine pedometer step count cut-points that associated with at least 30 min of MVPA during school hours. Cut-points were determined using the maximum Youden's J statistic (J max). For the total sample, the area-under-the-curve (AUC) was 0.77 (p < 0.001) with a pedometer cut-point of 5505 steps (J max = 0.46, Sensitivity = 63%, Specificity = 84%; Accuracy = 76%). Step counts showed greater diagnostic ability in girls (AUC = 0.81, p < 0.001; Cut-point = 5306 steps; Accuracy = 78.8%) compared to boys (AUC = 0.72, p < 0.01; Cut-point = 5786 steps; Accuracy = 71.4%). Pedometer step counts showed good diagnostic ability in girls and fair diagnostic ability in boys for discriminating children that met at least 30 min of MVPA during school hours.     

Pedometer-assessed physical activity of Singaporean youths

ObjectiveThe aim of the study was to investigate the pedometer-assessed physical activity of Singaporean youths using an objective measurement of physical activity.Methods and resultsPedometer step count was monitored over the entire week in 877 participants aged 9–18 years in three schooling cohorts [primary (age, 9–12 years; n = 150 males; 156 females), secondary (age, 13–16 years; n = 137 males; 138 females) and junior college (age, 17–18 years; n = 140 males; 156 females)] in Singapore during July to September 2009. Analyses identified significant main effects for step count taken outside of school compared to within school (mean (SD): 5568 (4796) vs. 3881 (3149), p < 0.05). However, no significant difference was found for steps accumulated within or outside school in boys and girls across the schooling levels (steps × sex × level interaction, p > 0.05). Step counts were not significantly different between weekdays or weekends (9719 (6063) vs. 9483 (8056), p > 0.05), across schooling levels and between male and female participants (sex × level and steps × level × sex interactions, all p > 0.05).ConclusionStep count decline is drastic for male adolescents after primary school but remains low across the schooling levels for female participants. Aggregated daily step count fell short by up to 35% of the 16,000 and 13,000 steps recommended respectively for male and female youths.     

Dog walking among adolescents: Correlates and contribution to physical activity

PurposeTo assess the association of dog walking with adolescents' moderate-to-vigorous physical activity (MVPA) and body mass index (BMI), and identify correlates of dog walking.Methods/designParticipants were 12–17 year-olds (n = 925) from the Baltimore, MD and Seattle, WA regions. Differences in accelerometer-assessed minutes/day of MVPA and self-reported BMI (percentile) were compared among adolescents (1) without a dog (n = 441) and those with a dog who (2) did (≥ 1 days/week, n = 300) or (3) did not (n = 184) walk it. Correlates of (1) dog walking (any vs. none) among adolescents with dogs (n = 484), and (2) days/week of dog walking among dog walkers (n = 300) were investigated. Potential correlates included: demographic, psychosocial, home environment, perceived neighborhood environment, and objective neighborhood environment factors.Results52% of adolescents lived in a household with a dog, and 62% of those reported dog walking ≥ 1 day/week. Dog walkers had 4–5 more minutes/day of MVPA than non-dog-walkers and non-dog-owners. BMI was not associated with dog walking or ownership. Among households with dogs, adolescents who lived in objectively walkable neighborhoods were 12% more likely to walk their dog than those in less walkable neighborhoods. Among dog walkers, having a multi-family home, college-educated parent, lower perceived traffic safety, higher street connectivity and less mixed use were related to more days/week of dog walking.ConclusionsDog walkers had 7–8% more minutes/day of MVPA than non-dog walkers, and correlates of dog walking were found at multiple levels of influence. Results suggest multilevel interventions that include both environmental and psychosocial components to increase dog walking should be evaluated.     

The association between physical activity and liver fat after five years of follow-up in a primary prevention multi-ethnic cohort

Objective: Excess liver fat (LF) is associated with dyslipidemia, insulin resistance and cardiovascular disease. Evidence suggests that there is an independent relationship between physical activity (PA) and LF although little is known of the role of PA intensity in reducing LF. The purpose was to evaluate whether meeting PA guidelines, the amount of PA and the intensity of PA at baseline were associated with LF after five-years.Methods: Men and women (n = 478) living in Vancouver, Canada of Aboriginal, Chinese, European or South Asian background completed baseline measurements in 2004–2005. Liver fat was assessed using CT scans at 5-year follow-up, and PA using a PA questionnaire at baseline as well as demographics and anthropometry.Results: In separate unadjusted models, meeting moderate–vigorous PA (MVPA) guidelines (p = 0.009), vigorous PA (p = 0.002) and MVPA (p = 0.017) but not moderate PA (p = 0.068) was predictive of LF at five years (p = 0.009). In multiple linear regression models, when adjusted for covariates, meeting MVPA guidelines and MVPA with LF at five years was no longer significant (p > 0.05) while vigorous PA remained significant (p = 0.021).Conclusion: Meeting PA guidelines through MVPA may not be adequate to prevent the accumulation of LF and PA guidelines may require revision. Vigorous PA should be encouraged to prevent LF accumulation.     

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.     

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.