Patterns of weekday and weekend physical activity in youth in 2 Canadian provinces

Effects of Universal School-Based Parental Support for Children's Healthy Diet and Physical Activity-the Healthy School Start Plus Cluster-Randomised Controlled Trial

Health promotion from an early age is key to preventing unhealthy weight development in childhood, and parental involvement is essential. The school-based Healthy School Start intervention aims to promote healthy dietary and activity habits in the home environment and prevent child obesity through parental support. This study evaluated the effectiveness of the third iteration of the programme on children's dietary and activity behaviours, and body composition through a cluster-randomised controlled trial. The trial included 17 schools (8 intervention) in disadvantaged areas in mid-Sweden with 353 families with 5- to 7-year-old children. The primary outcomes were intake of selected healthy and unhealthy foods and beverages measured using photography. Secondary outcomes were physical activity and sedentary time measured by accelerometry, and measured weight and height. All outcomes were assessed at baseline and post-intervention (8 months). Linear multi-level regression showed significant favourable effects of the intervention for intake of sweet beverages (b =  - 0.17, p = 0.04), intake of healthy foods (b = 0.11, p = 0.04), and more time in moderate to vigorous physical activity during weekdays (b = 5.68, p = 0.02). An unfavourable sub-group effect of the intervention was found for children from families with low education regarding sedentary time on weekends (b = 23.04, p = 0.05). The results align with the previous two trials of the programme, indicating that school-based parental support is a useful approach for health promotion in young children in disadvantaged areas. Trial registration: ClinicalTrials.gov: No. NCT03390725, retrospectively registered on January 4, 2018, https://clinicaltrials.gov/ct2/show/NCT03390725 .

Isotemporal substitution of accelerometer-derived sedentary behavior and physical activity on physical fitness in young children

This study investigates the effects of different types of physical activity (PA) on the physical fitness (PF) of young children in Japan, with a particular focus on how substituting sedentary behavior (SB) with active behaviors influences PF. We conducted a cross-sectional analysis of 1843 participants aged 3-6 years from northeastern Japan. Using triaxial accelerometers, we quantified PA, and PF was assessed via standardized tests. The innovative application of isotemporal substitution modeling (ISM) allowed us to analyze the impact of reallocating time from SB to more active states, specifically moderate-to-vigorous physical activity (MVPA) and light physical activity (LPA). Our findings reveal a robust association between increased MVPA and enhanced PF outcomes, underscoring the health benefits of reducing SB. Notably, replacing SB with LPA also showed beneficial effects on certain PF metrics, indicating LPA's potential role in early childhood fitness. These results highlight the critical importance of promoting MVPA and minimizing sedentary periods to bolster PF in young children. The study offers vital insights for shaping public health policies and emphasizes the need to cultivate an active lifestyle from an early age to secure long-term health advantages.

What are the important factors influencing the physical activity level of junior high school students: a cross-sectional survey

Background

Engaging in regular physical activity has been consistently linked to improved physical health and academic performance. Despite its known benefits, there is a concerning trend of decreased physical activity among children globally. The study primarily aims to investigate the level of physical activity among junior high school students in Taiyuan and analyse the main affecting factors from a socio-ecological perspective.

Methods

A cross-sectional study was conducted, involving 650 junior high school students from 7 schools in Taiyuan, and 648 valid questionnaires were ultimately collected. The data on students' physical activity levels were collected through the Children's Leisure Activities Study Survey Questionnaire, and the data on factors affecting students' physical activity were collected through the Student Perceived Factors Affecting Physical Activity Questionnaire.

Results

In this study, students from the 7th, 8th, and 9th grades participated in physical activities, averaging 214.500 min per week in moderate-intensity and 25.000 min in high-intensity activities, cumulatively averaging 280.000 min weekly. Notably, a significant disparity (p = 0.012) was observed in the combined duration of moderate and high-intensity activities, with male students engaging more time compared to their female counterparts (307.500 vs. 255.000 min). This variance extended across different grades, particularly evident in 8th graders who recorded the highest weekly high-intensity activity duration (31.000 min) and overall physical activity time (320.500 min), surpassing the 7th graders(p = 0.007 for high-intensity activities). Furthermore, an exploratory factor analysis of a 32-item questionnaire, designed to identify determinants of physical activity, revealed six principal components. These components were found to positively correlate with both moderate and high-intensity physical activities.

Conclusion

Results emphasize that educational institutions and community programs should collaborate to offer engaging weekend physical activity programs. Schools should develop and implement tailored physical education curricula addressing gender and grade differences. Furthermore, schools and local governments should invest in high-quality sports equipment and facilities.

Exploring an objective measure of overactivity in children with rare genetic syndromes

BACKGROUND

Overactivity is prevalent in several rare genetic neurodevelopmental syndromes, including Smith-Magenis syndrome, Angelman syndrome, and tuberous sclerosis complex, although has been predominantly assessed using questionnaire techniques. Threats to the precision and validity of questionnaire data may undermine existing insights into this behaviour. Previous research indicates objective measures, namely actigraphy, can effectively differentiate non-overactive children from those with attention-deficit hyperactivity disorder. This study is the first to examine the sensitivity of actigraphy to overactivity across rare genetic syndromes associated with intellectual disability, through comparisons with typically-developing peers and questionnaire overactivity estimates.

METHODS

A secondary analysis of actigraphy data and overactivity estimates from The Activity Questionnaire (TAQ) was conducted for children aged 4-15 years with Smith-Magenis syndrome (N=20), Angelman syndrome (N=26), tuberous sclerosis complex (N=16), and typically-developing children (N=61). Actigraphy data were summarized using the M10 non-parametric circadian rhythm variable, and 24-hour activity profiles were modelled via functional linear modelling. Associations between actigraphy data and TAQ overactivity estimates were explored. Differences in actigraphy-defined activity were also examined between syndrome and typically-developing groups, and between children with high and low TAQ overactivity scores within syndromes.

RESULTS

M10 and TAQ overactivity scores were strongly positively correlated for children with Angelman syndrome and Smith-Magenis syndrome. M10 did not substantially differ between the syndrome and typically-developing groups. Higher early morning activity and lower evening activity was observed across all syndrome groups relative to typically-developing peers. High and low TAQ group comparisons revealed syndrome-specific profiles of overactivity, persisting throughout the day in Angelman syndrome, occurring during the early morning and early afternoon in Smith-Magenis syndrome, and manifesting briefly in the evening in tuberous sclerosis complex.

DISCUSSION

These findings provide some support for the sensitivity of actigraphy to overactivity in children with rare genetic syndromes, and offer syndrome-specific temporal descriptions of overactivity. The findings advance existing descriptions of overactivity, provided by questionnaire techniques, in children with rare genetic syndromes and have implications for the measurement of overactivity. Future studies should examine the impact of syndrome-related characteristics on actigraphy-defined activity and overactivity estimates from actigraphy and questionnaire techniques.

Understanding Accelerated Summer Body Mass Index Gain by Tracking Changes in Children's Height, Weight, and Body Mass Index Throughout the Year

Background: Drivers of summer body mass index (BMI) gain in children remain unclear. The Circadian and Circannual Rhythm Model (CCRM) posits summer BMI gain is biologically driven, while the Structured Days Hypothesis (SDH) proposes it is driven by reduced structure. Objectives: Identify the mechanisms driving children's seasonal BMI gain through the CCRM and SDH. Methods: Children's (N = 147, mean age = 8.2 years) height and weight were measured monthly during the school year, and once in summer (July-August). BMI z-score (zBMI) was calculated using CDC growth charts. Behaviors were measured once per season. Mixed methods regression estimated monthly percent change in children's height (%HΔ), weight (%WΔ), and monthly zBMI for school year vs. summer vacation, seasonally, and during school months with no breaks vs. school months with a break ≥1 week. Results: School year vs. summer vacation analyses showed accelerations in children's %WΔ (Δ = 0.9, Standard Error (SE) = 0.1 vs. Δ = 1.4, SE = 0.1) and zBMI (Δ = -0.01, SE = 0.01 vs. Δ = 0.04, SE = 0.3) during summer vacation, but %HΔ remained relatively constant during summer vacation compared with school (Δ = 0.3, SE = 0.0 vs. Δ = 0.4, SE = 0.1). Seasonal analyses showed summer had the greatest %WΔ (Δ = 1.8, SE = 0.4) and zBMI change (Δ = 0.05, SE = 0.03) while %HΔ was relatively constant across seasons. Compared with school months without a break, months with a break showed higher %WΔ (Δ = 0.7, SE = 0.1 vs. Δ = 1.6, SE = 0.2) and zBMI change (Δ = -0.03, SE = 0.01 vs. Δ = 0.04, SE = 0.01), but %HΔ was constant (Δ = 0.4, SE = 0.0 vs. Δ = 0.3, SE = 0.1). Fluctuations in sleep timing and screen time may explain these changes. Conclusions: Evidence for both the CCRM and SDH was identified but the SDH may more fully explain BMI gain. Interventions targeting consistent sleep and reduced screen time during breaks from school may be warranted no matter the season.

Sleep Time, Physical Activity, and Screen Time among Montana American Indian Youth

The purpose of this study is to describe sleep, PA, and screen time behaviors among rural American Indian (AI) youth, stratified by sex and grade, to better understand how to address these health behaviors in AI youth. Body composition, a screen time survey, and demographic information were collected from 65 AI youth. Accelerometers were worn for 7 days. Sixty percent were overweight or obese. Sleep did not differ by sex or grade, with an actigraphy-based total sleep time (aTST) of 7.8 h per night. Boys had significantly more light PA (p = 0.002) and vigorous PA (p = 0.01) compared to girls. Screen time did differ by sex but not by grade, with girls in the sixth and seventh grades reporting more screen time than boys, but boys in the eighth grade reporting more screen time than girls. Despite sex differences in screen time, high levels of screen time and obesity and low levels of PA and sleep are a concern in this population.

Physical Activity, Sleep, and Demographic Patterns in Alaska Native Children and Youth Living in Anaktuvuk Pass

Physical activity (PA), sleep, and weight are important factors for youth health. However, data about these factors are unknown in youth living in isolated Alaska Native communities. This study aims to assess PA, sleep, height and weight in elementary through high school students living in Anaktuvuk Pass. Fourteen children (<12) and 24 youths (12-20) volunteered to participate in this study. PA and sleep data were collected with actigraphy. Height and weight were assessed with standard procedures. Demographics were collected via survey. Results show that 10.53% and 18.42% of participants were overweight and obese, respectively. Average bedtime was 00:15 am and wake time 08:23 am. Total sleep time was 498.21 min. Participants averaged 477.64 min in sedentary activity, 297.29 min in light activity, 150.66 min in moderate activity, and 18.05 min in vigorous activity. Adjusted models suggest that high school students engage in significantly more sedentary activity, and significantly less light, moderate, and vigorous activity compared to those in middle and elementary school. All students engaged in less moderate and vigorous activity on the weekend compared to the weekday. Data suggest that as children age they become more sedentary. Future studies should focus on increasing daily PA in high school students while considering other obesogenic factors.

COVID-19 Leads to Accelerated Increases in Children's BMI z-Score Gain: An Interrupted Time-Series Study

INTRODUCTION

The COVID-19 pandemic may have negatively impacted children's weight status owing to the closure of schools, increased food insecurity and reliance on ultraprocessed foods, and reduced opportunities for outdoor activity.

METHODS

In this interrupted time-series study, height and weight were collected from children (n=1,770 children, mean age=8.7 years, 55.3% male, 64.6% Black) and were transformed into BMI z-score in each August/September from 2017 to 2020. Mixed-effects linear regression estimated yearly BMI z-score change before the COVID-19 pandemic year (i.e., 2017-2019) and during the COVID-19 pandemic year (i.e., 2019-2020). Subgroup analyses by sex, race (i.e., Black, White, other race), weight status (overweight or obese and normal weight), and grade (i.e., lower=kindergarten-2nd grade and upper=3rd-6th grade) were conducted.

RESULTS

Before the COVID-19 pandemic, children's yearly BMI z-score change was +0.03 (95% CI= -0.10, 0.15). Change during the COVID-19 pandemic was +0.34 (95% CI=0.21, 0.47), an acceleration in BMI z-score change of +0.31 (95% CI=0.19, 0.44). For girls and boys, BMI z-score change accelerated by +0.33 (95% CI=0.16, 0.50) and +0.29 (95% CI=0.12, 0.46), respectively, during the pandemic year. Acceleration in BMI z-score change during the pandemic year was observed for children who were Black (+0.41, 95% CI=0.21, 0.61) and White (+0.22, 95% CI=0.06, 0.39). For children classified as normal weight, BMI z-score change accelerated by +0.58 (95% CI=0.40, 0.76). Yearly BMI z-score change accelerated for lower elementary/primary (+0.23, 95% CI=0.08, 0.37) and upper elementary/primary (+0.42, 95% CI=0.42, 0.63) children.

CONCLUSIONS

If similar BMI z-score accelerations occurred for children across the world, public health interventions to address this rapid unhealthy BMI gain will be urgently needed.

Changes in Physical Fitness during Summer Months and the School Year in Austrian Elementary School Children-A 4-Year Longitudinal Study

Even though physical fitness is an important component in children's health and well-being, there has been a decline in physical fitness over the last several decades. The present study examined potential differences in the development of physical fitness during the academic year and summer vacation in Austrian elementary-school children. A total of 214 children (52.3% boys) completed the German motor test in the fall (after summer vacation) and spring (prior to summer vacation) of every grade throughout their elementary school years. This resulted in eight assessments of cardio-respiratory endurance, muscular fitness, flexibility, speed, agility, and balance over a 4-year period. As expected, physical fitness increased with age but the improvement in cardio-respiratory endurance and muscular fitness was more pronounced during summer vacation (p < 0.01), while the improvement in speed was more pronounced during the academic year (p < 0.01). These results indicate an influence of weather conditions on health-enhancing physical activity in addition to structural and social support. Particularly in geographical regions with cold winters and shorter days, health-enhancing physical activity may be limited. Accordingly, schools need to provide additional opportunities to ensure an adequate amount of physical activity that stimulates the development of physical fitness.

Influence of weather conditions on children’s school travel mode and physical activity in 3 diverse regions of Canada

Children who engage in active school transportation (AST) have higher levels of physical activity (PA). Climate and weather were shown to influence adults’ daily travel behaviours, but their influence on children’s AST and PA has been less examined. This study examined the influence of weather conditions on children’s AST and overall PA. Children in grades 4 to 6 (N = 1699; age, 10.2 ± 1.0 years) were recruited in schools located in urban, suburban and rural areas, stratified by area-level socioeconomic status, in 3 different regions of Canada (Trois-Rivières, Québec; Ottawa, Ontario; Vancouver, British Columbia). Mode of school travel was self-reported and physical activity was measured using a pedometer. We used publicly available data on total precipitation and early morning temperature. AST increased with temperature only among girls. Daily precipitation was negatively associated with boys’ and girls’ PA while warmer temperature was associated with increased PA on weekend days. We also observed that season and region moderated the relationship between weather conditions and children’s physical activity behaviours. Our results suggest that daily weather variations influence children’s AST and PA to a greater extent than seasonal variations. Interventions designed to help children and families adapt to weather-related barriers to AST and PA are needed.

Novelty: In Canada, weather conditions may influence children’s active behaviours daily. Associations between weather conditions, choice of travel mode and physical activity vary by sex, season, and region. Weather affects children's PA differently during the week than on weekends.

Examining Factors of Accelerometer-Measured Sedentary Time in a Sample of Rural Canadian Children

The aim of this study was to examine potential child-level and day-level factors of accelerometer-measured sedentary time in a sample of rural Canadian children. Children (n = 86) from rural Northwestern Ontario participated in this study. Children’s sedentary times were identified and logged using an accelerometer. Child-level data (socio-demographic, household, and environment) came from surveys of children and their parents and a passively logging global positioning unit. Day-level data on day type (weekday/weekend) and weather (temperature, precipitation) were based on the dates of data collection and meteorological data came from the closest Environment Canada weather station. Cross-classified regression models were used to assess the relationship between child-level and day-level correlates of sedentary time. Boys were less sedentary than girls (b = −30.53 p = 0.01). For each one-year age increase, children’s sedentary time increased (b = 12.79 p < 0.01). This study indicates a difference in sedentary time based on a child’s age and gender. However, family, environmental, and weather characteristics did not influence sedentary time in this sample. Health practitioners who deliver care for northern rural youth can provide targeted health advice regarding sedentary time and consider gender and age to be risk factors for these behaviors.

Influence of meeting weekday and weekend step count recommendations on weight statusin children

The purpose of this study was to investigate the relationship between meeting step count recommendations during the weekday and weekend and the weight status in school-aged children. A convenience sample of 855 fourth and fifth grade students (9.7 ± 1.0 years) was recruited from 4 elementary schools located in the Western United States. Body Mass Index (BMI) was calculated using standard procedures and then stratified to weight status categories (healthy weight, overweight/obese) using age- and sex-specific percentiles. Step counts were monitored for seven consecutive days using NL-1000 piezoelectric pedometers. A multilevel generalized linear mixed effect model was used to estimate the odds ratios of meeting segmented step counts recommendations and weight status. Students meeting weekday step count recommendations associated with 39% lower odds of overweight/obesity compared to those not meeting any recommendations (P = 0.02). Those meeting both weekday and weekend recommendations associated with 67% lower odds of overweight/obesity compared to children not meeting any recommendations (P = 0.01). Meeting weekend step count recommendations did not associate with weight status. This study supports the positive relationship between segmented step counts and the healthy weight status of school-aged children.

The Gender Difference in Association between Home-Based Environment and Different Physical Behaviors of Chinese Adolescents

Purpose: The aim of this study was to evaluate the home-based physical activity (PA) environmental characteristics, and different types of physical behavior level of adolescents in different genders, and explore the impact of different domains of home-based PA environmental factors on different physical behaviors of adolescents in different genders. Methods: Five hundred forty-four adolescents aged from 12 to 18 years old (males: n = 358, females: n = 186) and their parents were analyzed in this cross-sectional survey. The volume of various physical behaviors of all adolescent subjects were measured by the ActiGraph wGT3X-BT accelerometer, and the level in different domains of home-based environmental characteristics were assessed by the Gattshall’s home-based PA environment questionnaire, which was answered by adolescents’ parents. The difference in the volume of different physical behaviors was examined using Kruskal–Wallis analysis. The difference in home physical environment and home social environment for adolescents was examined using one-way analysis of variance (ANOVA). Multiple linear regression analysis in the adjusted model was used to evaluate the influence of different home-based PA environmental domains (PA availability, PA accessibility, Parental role-modeling of PA, and Parental policies around PA) on different physical behaviors (sedentary behavior, SB; light-intensity physical activity, LPA; and moderate-vigorous physical activity, MVPA) of adolescents (boys and girls). Results: The volume of LPA and MVPA, the score of PA accessibility in the home physical environment, and the score of home social environment of boys are significantly higher than those of girls, while the SB volume of boys is significantly lower than that of girls. The PA availability, the parents’ role-modeling of PA in same-sex parent–child dyads, and the parents’ policies around PA in opposite-sex parent–child dyads are significantly associated with adolescents’ decreased SB and increased LPA and MVPA. Conclusion: There is significant gender difference in adolescents’ physical behaviors and home-based environmental characteristics, as well as in the association between adolescents’ physical behaviors and their home-based environment. The PA availability, the parents’ role-modeling of PA in same-sex parent–child dyads, and the parents’ policies around PA in opposite-sex parent–child dyads can significantly promote adolescents’ healthy physical behaviors.

Accelerometer-measured physical activity and sedentary behavior in Chinese children and adolescents: a systematic review and meta-analysis

OBJECTIVE

To synthesize evidence on accelerometer-measured moderate-to-vigorous physical activity (MVPA) and sedentary behavior (SB) levels of Chinese children and adolescents.

STUDY DESIGN

This is both a systematic review and meta-analysis study.

METHODS

Online databases were searched for studies published from January 2009 up to February 2019. These studies reported accelerometer-measured daily minutes of MVPA and/or SB among Chinese children and adolescents. Random-effects meta-analysis was used to separately pool the time spent in MVPA and SB.

RESULTS

Of 4754 records, 20 studies were included in the meta-analysis. Sample sizes ranged from 96 to 2163. The meta-analysis showed that Chinese children and adolescents spent 41.11 min/day in MVPA and 529.83 min/day in SB averagely. Boys spent more time in MVPA compared with girls (P = 0.01). Children accumulated more MVPA time than adolescents (P = 0.05), and children spent less time in SB than adolescents (P = 0.05). Unlike weekdays, SB was lower on weekends (P = 0.02). There were significant differences in children and adolescents' MVPA time in regions (P < 0.001).

CONCLUSIONS

MVPA level in Chinese children and adolescents is well below international recommendations, and their SB level is very high.

Examining weather-related factors on physical activity levels of children from rural communities

OBJECTIVE

The objective was to examine the influence of weather on moderate-to-vigorous physical activity (MVPA) and light physical activity (LPA) levels of children aged 8-14 years from rural communities, an understudied Canadian population.

METHODS

Children (n = 90) from four communities in rural Northwestern Ontario participated in this study between September and December 2016. Children's MVPA and LPA were measured using an Actical accelerometer and demographic data were gathered from surveys of children and their parents. Weather data were collected from the closest weather station. Cross-classified regression models were used to assess the relationship between weather and children's MVPA and LPA.

RESULTS

Boys accumulated more MVPA than girls (b = 26.38, p < 0.01), children were more active on weekdays as compared with weekends (b = - 16.23, p < 0.01), children were less active on days with precipitation (b = - 22.88, p < 0.01), and higher temperature led to a significant increase in MVPA (b = 1.33, p  < 0.01). As children aged, they accumulated less LPA (b = - 9.36, p < 0.01) and children who perceived they had higher levels of physical functioning got more LPA (b = 25.18, p = 0.02). Similar to MVPA, children had higher levels of LPA on weekdays (b = - 37.24, p < 0.01) as compared to weekend days and children accumulated less LPA (b = -50.01, p < 0.01) on days with rain.

CONCLUSION

The study findings indicate that weather influences rural children's MVPA and LPA. Future research is necessary to incorporate these findings into interventions to increase rural children's overall PA levels and improve their overall health.

Understanding factors associated with children achieving recommended amount of MVPA on weekdays and weekend days

Low levels of moderate-to-vigorous physical activity (MVPA) are consistently reported for children from industrialized countries. Perennially inadequate levels of MVPA have been linked to increased chronic disease risks. Very few studies have compared physical activity levels among children from geographically diverse places, and how they differ on weekdays versus weekends. The purpose of this research is to examine the factors that influence whether children achieve 60 min of MVPA on weekdays compared to weekend days. Data were analyzed on children (n = 532) aged 8-14 years from communities in Southern and Northern Ontario, Canada that participated in the study between 2009 and 2016. Children's MVPA was measured using an Actical accelerometer, environmental features measured with a geographic information system, and demographic data came from child/parent surveys. Variables were selected using a least absolute shrinkage and selection operator. The variables were entered into logistic regression models to assess the relationship between children meeting the MVPA guidelines. During the week, boys were more active than girls (OR = 4.652 p < 0.001) and as age increased children were less likely to reach the MVPA guidelines (OR = 0.758 p = 0.013). On weekends boys were still more likely to meet the guidelines (OR = 1.683 p = 0.014) and children living in rural Northern Ontario were more likely to reach the MVPA guidelines compared to all groups in Southern Ontario. The findings indicate that different variables influence whether children meet the MVPA guidelines on weekdays compared to weekends. Comparing weekdays and weekends provides more useful information for creating effective MVPA interventions.

Weekly variation in diet and physical activity among 4-75-year-old Danes

OBJECTIVE

To compare dietary intake and physical activity (PA) between days of the week in a large sample of the Danish population; furthermore, to investigate the influence of gender and age as determinants for weekly variation.

DESIGN

Analysis was based on cross-sectional data from the Danish National Survey of Diet and Physical Activity 2011-2013. Dietary intake and PA were assessed by 7 d of pre-coded food diaries and pedometer-determined step counts. Dietary intake and PA on weekdays (Monday-Thursday), Friday, and weekend days (Saturday and Sunday) were compared using linear mixed models.

SETTING

Survey with national representation, conducted in Denmark between 2011 and 2013.

PARTICIPANTS

A random sample of 4-75-year-old Danes, n 3934 and n 3530 in analysis of dietary intake and PA, respectively.

RESULTS

Energy intake during Friday and weekend days was 7-20 % higher compared with weekdays, while step counts were 10 and 17 % lower on Saturday and Sunday, respectively (all P < 0·001). Energy density of liquids and solids, consumption of added sugar, alcohol, discretionary foods, beer, wine and sugar-sweetened beverages were substantially higher, and consumption of dietary fibre, vegetables, fruit and wholegrain products were lower, during Friday and weekend days compared with weekdays (all P < 0·001). The observed patterns were present across gender and age, although weekly variation was most pronounced among children and relatively modest among the elderly.

CONCLUSIONS

Weekend health behaviours of Danes display less favourable eating and PA behaviour compared with weekdays, making the weekend an important target for public health interventions aiming to improve dietary intake and PA behaviour.

Sleep and Physical Activity Patterns in Urban American Indian Children

Objectives: In this study, we examined patterns of obesity, physical activity (PA), sleep, and screen time in urban American Indian (AI) youth in the 6th-8th grade. Methods: A youth sample (N = 36) from 3 middle schools was recruited to participate in this observational sample of convenience. Youth completed a demographic and screen time survey, measurements of height and weight, and wore a wrist accelerometer continuously for 7 days to assess PA and sleep. Results: Approximately 42% of participants were overweight or obese. Average weekday screen time was 254.7±98.1 minutes. Compared to weekdays, weekend sedentary activity increased (weekday, 159.2±81.1 minutes vs weekend, 204.3±91.7 minutes; p = .03) and vigorous PA (weekday, 20.9±19.1 minutes vs weekend, 5.7±8.1 minutes; p = .0001) and moderate-to-vigorous PA (weekday, 192.65±62.3 minutes vs weekend, 141±71.7 minutes; p = .002) decreased. Compared to weekdays, weekend total sleep time (weekday, 512.8±48.6 minutes vs weekend, 555.3±84.3 minutes; p = .007) and time in bed (weekday, 487.3±49.6 minutes vs weekend, 528.6±71.2 minutes; p = .01) increased. Conclusions: Weekday to weekend shifts in PA and sleep must be considered when designing targeted obesity prevention interventions.

Longitudinal Trajectories of Children's Physical Activity and Sedentary Behaviors on Weekdays and Weekends

BACKGROUND

The objective was to examine changes of children's time spent in sedentary, light physical activity, moderate to vigorous physical activity (MVPA), and estimated energy expenditure (EE) rates during weekdays and weekends across 3 years.

METHODS

An initial sample of 261 children's (mean age = 7.81 y) 5-day physical activity and EE were assessed annually via accelerometry across 3 years using repeated-measures multivariate analysis of variance. The outcome variables were time spent in sedentary, light physical activity, MVPA, and kilocalories per day for weekdays and weekends.

RESULTS

A significant decrease in MVPA and EE occurred during weekdays across the 3 years (P = .01). Only the second-year data demonstrated an increase (+2.49 min) in weekend MVPA (P = .04). Children's sedentary time during weekdays increased significantly in years 1 and 2 (P = .01), yet significantly decreased in the third year (-44.31 min). Children's sedentary time during weekends significantly decreased in the first year (-27.31 min), but increased in the following 2 years (P = .01). Children's light physical activity demonstrated a statistically significant increase in year 2 (+3.75 min) during weekdays (P = .05).

CONCLUSIONS

Children's MVPA and EE generally declined during weekdays but were maintained during weekends across a 3-year time span. Children may benefit most from weekday intervention strategies.

The relationship between transport-to-school habits and physical activity in a sample of New Zealand adolescents

OBJECTIVES

Adolescents using active transport (AT) to school have higher levels of physical activity (PA) compared with motorized transport (MT) users. This study compared school day and weekend day PA in adolescents using AT, MT, or combined AT and MT (AT + MT) to travel to school.

METHODS

Adolescents (n = 314; age: 14.7 ± 1.4 years; 32.8% boys) from Dunedin (New Zealand) wore an accelerometer for 7 days and completed a self-reported survey regarding mode of transport to school (73 AT, 56 AT + MT, and 185 MT). Data were analyzed using t tests, analysis of variance, and χ ² tests.

RESULTS

Although the proportion of adolescents meeting PA guidelines significantly differed among transport groups (AT, 47.9%; AT + MT, 46.4%; MT, 33.5%; p = 0.048; overall, 39.2%), the observed differences were due mainly to girls. Compared with MT, AT and AT + MT engaged in more moderate-to-vigorous PA (MVPA) per day (AT: 61.2 ± 23.2 min; AT + MT: 59.6 ± 21.7 min; MT: 52.5 ± 19.6 min; p = 0.004; p < 0.001, adjusted for gender), per school day and before school. Immediately after school (15:00-16:00), AT engaged in significantly more MVPA compared with AT + MT and MT. No differences in MVPA between the groups were observed in the late afternoon/early evening period during school days or on weekend days.

CONCLUSION

Compared with MT users, adolescent girls using AT or AT + MT accumulated more MVPA during school commute time. AT + MT to school is also a plausible way to increase adolescent girls' PA when AT only is not feasible.

Stay in or play out? The influence of weather conditions on physical activity of grade 5 children in Canada

OBJECTIVES

Regular physical activity (PA) in children is essential for their development and prevention of overweight and obesity. Little is known about the effect of day-to-day variations in weather conditions on PA levels in school-aged children, particularly with regard to school compared to non-school days and girls compared to boys.

METHODS

Daily step count (7:00 a.m.-9:00 p.m.) from 972 grade 5 students aged 10-11 years from 60 schools across Alberta, Canada, was collected using time-stamped pedometers (minimum wear time of two school and one non-school days) during March-June 2013. Time-matched weather conditions (actual and feels-like temperature, cloud coverage, and precipitation amount) were obtained from local weather stations in Alberta during the same period. Multilevel mixed-effect regression models were used to estimate the effect of each weather condition on daily step count.

RESULTS

A 1 °C increase in feels-like temperature was associated with 26 more steps/day (p < 0.05), while 1-unit increase in cloud coverage was associated with 61 fewer steps/day (p < 0.01). Compared to no precipitation, heavy precipitation (> 5 mm/day) was associated with 1022 fewer steps/day (p < 0.01). Students' PA levels were associated with weather conditions more on non-school vs. school days and more among girls vs. boys.

CONCLUSION

Results suggest that daily weather conditions can affect PA in school children, particularly outside school hours, and should be considered when evaluating PA levels or designing interventions to promote PA in children. Findings provide support for increased investment toward creating weather-appropriate physical activity opportunities for wet and colder days to prevent PA decline in children during inclement weather conditions.

Gaps in Knowledge and the Need for Patient-Partners in Research Related to Physical Activity and Type 1 Diabetes: A Narrative Review

Regular physical activity (PA) is a cornerstone in the management of complications associated with type 1 diabetes (T1D). Most national guidelines advocate for regular PA for persons living with T1D, however the evidence to support these recommendations has not be reviewed recently. Additionally, in an era of patient-centered care and patient oriented research, the role of patient partners in the area of PA and T1D interventions has never been explored. The purpose of this narrative review is to overcome these two gaps in the literature. Here we review selected epidemiological evidence and identify gaps in research that would add important information to guide practitioners and future guidelines. We also provide an overview of patient-oriented research projects co-developed with persons living with T1D. Significant gaps in the field include: (1) a lack of adequately powered prospective cohort studies using serial measures of PA and hard chronic disease end-points; (2) no multi-centered, highly powered, randomized controlled trials of PA, and long-term health outcomes; (3) little data on the role of new technologies to support PA-related behavior change, and (4) no trials that involved patients in the design and execution of PA-based clinical trials. This review provides a template for scientists and patient partners to develop future research priorities and agendas in the field.

Exploring the Effect of Perceptions on Children's Physical Activity in Varying Geographic Contexts: Using a Structural Equation Modelling Approach to Examine a Cross-Sectional Dataset

Most Canadian children are not meeting the recommended 60 min of moderate-to-vigorous physical activity per day. Research suggests that children’s perceptions of their environment have an influence on their physical activity behaviours, but there is a lack of generalizability among previous work. The purpose of this study was to assess the mediating effect of children’s perceptions of barriers to physical activity on the relationship between their environments and their level of moderate-to-vigorous physical activity (measured with accelerometers). Structural equation modelling stratified by gender was used to assess the research objective in a sample of 546 participants aged 8–14 years old from Northwestern and Southwestern Ontario, Canada. In both models stratified by gender, perceptions of barriers did not significantly mediate the relationship between urbanicity and physical activity. Independent of all other factors, there was no significant relationship between urbanicity and physical activity in girls, but there was in boys. These results offer insight into potential processes by which perceptions impact physical activity and provide initial information to further our understanding of the behavioural aspects of physical activity through multiple levels of analysis. Researchers must continue to improve efforts for quantifying the experience of children’s daily activity contexts.

Latent profile analysis of young adolescents' physical activity across locations on schooldays

PURPOSE

To investigate whether adolescents cluster into profiles based on where they accumulate moderate-to-vigorous physical activity (MVPA), if overall MVPA differs across profiles, and if walking to school and participant and neighborhood characteristics explain profile membership.

METHODS

Adolescents (N=528; mean age=14.12±1.44; 50% girls) wore accelerometers and Global Positioning Systems (GPS) trackers for 3.9±1.5 days to assess MVPA minutes in five locations: at home, at school, in home neighborhood, in school neighborhood, and other. Walking to school and participant characteristics were assessed by questionnaire, and neighborhood environment by Geographic Information Systems (GIS). Latent profile analysis (LPA) was used to identify profiles/groups of participants based on accumulation of physical activity across the five locations. Mixed-effects regression tested differences in overall MVPA, walking to school, and other characteristics across profiles.

RESULTS

Four initial profiles emerged: one Insufficiently Active profile and three "Active" profiles (Active Around School, Active Home Neighborhood, and Active Other Locations). The Insufficiently Active profile emerging from the first LPA (90% of participants) was further separated into four profiles in a second LPA: Insufficiently Active, and three additional "Active" profiles (Moderately-Active Around School, Moderately-Active Home Neighborhood, and Active At Home). Those in the six Active profiles had more overall MVPA (41.1-92.7 minutes/day) than those in the two Insufficiently Active profiles (34.5-38.3 minutes/day). Variables that differed across profiles included walking to school, sports/athletic ability, and neighborhood walkability.

CONCLUSIONS

Although most participants did not meet the MVPA guideline, the six Active profiles showed the places in which many adolescents were able to achieve the 60-minute/day guideline. The home and school neighborhood (partly through walking to school), "other" locations, and to a lesser extent the home, appeared to be key sources for physical activity that distinguished active from insufficiently active adolescents. Finding the right match between the individual and physical activity source/location may be a promising strategy for increasing active travel and MVPA in adolescents.

A Healthy School Start Plus for prevention of childhood overweight and obesity in disadvantaged areas through parental support in the school setting - study protocol for a parallel group cluster randomised trial

Background

Systematic reviews conclude that interventions to prevent overweight and obesity in children obtain stronger effects when parents are involved. Parenting practices and parent-child interactions shape children’s health-related behaviours. The Healthy School Start Plus intervention aims to promote healthy dietary habits and physical activity and prevent obesity in children through parental support in disadvantaged areas with increased health needs, delivered by teachers and school nurses. This protocol describes the design, outcome and process evaluation of the study.

Methods

Effectiveness of the intervention is compared to standard care within school health services. The 6-month programme, based on Social Cognitive Theory, consists of four components: 1) Health information to parents regarding the child; 2) Motivational Interviewing with the parents by the school nurse concerning the child; 3) classroom activities for the children by teachers; and 4) a web-based self-test of type-2 diabetes risk by parents. Effects will be studied in a cluster randomised trial including 17 schools and 352 six-year old children. The primary outcome is dietary intake of indicator foods, and secondary outcomes are physical activity, sedentary behaviour and BMI. Outcomes will be measured at baseline, at 6 months directly after the intervention, and at follow-up 18 months post baseline. Statistical analysis will be by mixed-effect regression analysis according to intention to treat and per protocol. Mediation analysis will be performed with parental self-efficacy and parenting practices. Quantitative and qualitative methods will be used to study implementation in terms of dose, fidelity, feasibility and acceptability. The hypothesis is that the programme will be more effective than standard care and feasible to perform in the school context.

Discussion

The programme is in line with the cumulated evidence regarding the prevention of childhood obesity: That schools should be a focal point of prevention efforts, interventions should involve multiple components, and include the home environment. If effective, it will fill a knowledge gap concerning evidence-based health promotion practice within school health services to prevent obesity, and in the long term reduce social inequalities in health.

Trial registration

The trial was retrospectively registered on January 4, 2018 and available online at ClinicalTrials.gov: No. NCT03390725.

After-school leisure time: physical activity and estimated caloric expenditure in schoolchildren from southeast Spain

Introducción. Por lo general, el periodo de ocio extraescolar es empleado por los escolares para realizar actividades físicas; sin embargo, se desconoce el nivel de actividad física de moderada a vigorosa intensidad (AFMV) y de gasto calórico registrados en ese periodo.Objetivo. Analizar los niveles de actividad física y gasto energético estimado durante el periodo de ocio extraescolar.Materiales y métodos. Participaron 408 escolares, con un rango de edad entre 11 y 12 años, siendo 205 niñas (11.21±0.41) y 203 niños (11.20±0.40) del sistema educativo español. Se siguió un diseño de tipo descriptivo relacional y de carácter transversal. Los escolares registraron la actividad física con el instrumento Previous Day Physical Activity Recall y su análisis se hizo a través del promedio de minutos realizando AFMV (>3 MET) y el gasto calórico extraído de los niveles de MET.Resultados. Se encontraron medias superiores para los hombres respecto a las mujeres, tanto en los minutos de AFMV (p<0.05) como en el gasto calórico (p<0.001) registrado.Conclusiones. El promedio de minutos de AFMV estimada por los escolares estudiados cumple con los valores diarios recomendados por la Organización Mundial de la Salud. Se debe prestar especial atención al género femenino y a la entrada a la adolescencia.

Summer Weight Gain and Fitness Loss: Causes and Potential Solutions

Over the past 3 decades, public health professionals have worked to stem the rising childhood obesity epidemic. Despite the field's best efforts, no progress has been made in reducing child obesity. One reason for this failure may be that obesity prevention and treatment efforts have predominately been delivered during the 9-month school year. However, recent evidence suggests that the summer, not the school year, is when unhealthy changes in body composition (ie, accelerated increases in percent body fat) and fitness losses occur. This unhealthy change in body composition and fitness loss during the summer could be explained by the "Structured Days Hypothesis," which posits that children engage in a greater number of unhealthy obesogenic behaviors on unstructured days when compared with structured days. Furthermore, the summer may be contributing to a widening "health gap" between children from low-income and middle- to upper-income families. During summer, fewer opportunities exist for children from low-income households to access healthy structured programs that do not require fees for participation. Moving forward, public health professionals should prioritize efforts to mitigate unhealthy changes in body composition and fitness loss during the summer by identifying ways to provide access to structured programming during this timeframe for children from low-income households.

Understanding differences between summer vs. school obesogenic behaviors of children: the structured days hypothesis

BACKGROUND

Although the scientific community has acknowledged modest improvements can be made to weight status and obesogenic behaviors (i.e., physical activity, sedentary/screen time, diet, and sleep) during the school year, studies suggests improvements are erased as elementary-age children are released to summer vacation. Emerging evidence shows children return to school after summer vacation displaying accelerated weight gain compared to the weight gained occurring during the school year. Understanding how summer days differ from when children are in school is, therefore, essential.

DISCUSSION

There is limited evidence on the etiology of accelerated weight gain during summer, with few studies comparing obesogenic behaviors on the same children during school and summer. For many children, summer days may be analogous to weekend days throughout the school year. Weekend days are often limited in consistent and formal structure, and thus differ from school days where segmented, pre-planned, restrictive, and compulsory components exist that shape obesogenic behaviors. The authors hypothesize that obesogenic behaviors are beneficially regulated when children are exposed to a structured day (i.e., school weekday) compared to what commonly occurs during summer. This is referred to as the 'Structured Days Hypothesis' (SDH). To illustrate how the SDH operates, this study examines empirical data that compares weekend day (less-structured) versus weekday (structured) obesogenic behaviors in U.S. elementary school-aged children. From 190 studies, 155 (~80%) demonstrate elementary-aged children's obesogenic behaviors are more unfavorable during weekend days compared to weekdays.

CONCLUSION

In light of the SDH, consistent evidence demonstrates the structured environment of weekdays may help to protect children by regulating obesogenic behaviors, most likely through compulsory physical activity opportunities, restricting caloric intake, reducing screen time occasions, and regulating sleep schedules. Summer is emerging as the critical period where childhood obesity prevention efforts need to be focused. The SDH can help researchers understand the drivers of obesogenic behaviors during summer and lead to innovative intervention development.

Fitness, fatness and the reallocation of time between children's daily movement behaviours: an analysis of compositional data

BACKGROUND

Movement behaviours performed over a finite period such as a 24 h day are compositional data. Compositional data exist in a constrained simplex geometry that is incongruent with traditional multivariate analytical techniques. However, the expression of compositional data as log-ratio co-ordinate systems transfers them to the unconstrained real space, where standard multivariate statistics can be used. This study aimed to use a compositional data analysis approach to examine the adiposity and cardiorespiratory fitness predictions of time reallocations between children's daily movement behaviours.

METHODS

This study used cross-sectional data from the Active Schools: Skelmersdale study, which involved Year 5 children from a low-income community in northwest England (n = 169). Measures included accelerometer-derived 24 h activity (sedentary time [ST], light physical activity [LPA], moderate-to-vigorous physical activity [MVPA], and sleep), cardiorespiratory fitness determined by the 20 m shuttle run test, objectively measured height, weight and waist circumference (from which zBMI and percent waist circumference-to-height ratio (%WHtR) were derived) and sociodemographic covariates. Log-ratio multiple linear regression models were used to predict adiposity and fitness for the mean movement behaviour composition, and for new compositions where fixed durations of time had been reallocated from one behaviour to another, while the remaining behaviours were unchanged. Predictions were also made for reallocations of fixed durations of time using the mean composition of three different weight status categories (underweight, normal-weight, and overweight/obese) as the starting point.

RESULTS

Replacing MVPA with any other movement behaviour around the mean movement composition predicted higher adiposity and lower CRF. The log-ratio model predictions were asymmetrical: when time was reallocated to MVPA from sleep, ST, or LPA, the estimated detriments to fitness and adiposity were larger in magnitude than the estimated benefits of time reallocation from MVPA to sleep, ST or LPA. The greatest differences in fitness and fatness for reallocation of fixed duration of MVPA were predicted at the mean composition of overweight/obese children.

CONCLUSIONS

Findings reinforce the key role of MVPA for children's health. Reallocating time from ST and LPA to MVPA in children is advocated in school, home, and community settings.

Dietary intake and prospective changes in cardiometabolic risk factors in children and youth

Only few studies examined the effect of diet on prospective changes in cardiometabolic (CM) risk factors in children and youth despite its importance for understanding the role of diet early in life for cardiovascular disease in adulthood. To test the hypothesis that dietary intake is associated with prospective changes in CM risk factors, we analyzed longitudinal observations made over a period of 2 years among 448 students (aged 10-17 years) from 14 schools in Canada. We applied mixed effect regression to examine the associations of dietary intake at baseline with changes in body mass index, waist circumference (WC), systolic and diastolic blood pressure (SBP and DBP), and insulin sensitivity score between baseline and follow-up while adjusting for age, sex, and physical activity. Dietary fat at baseline was associated with increases in SBP and DBP z scores (per 10 g increase in dietary fat per day: β = 0.03; p < 0.05) and WC (β = 0.31 cm; p < 0.05) between baseline and follow-up. Every additional gram of sodium intake at baseline was associated with an increase in DBP z score of 0.04 (p < 0.05) between baseline and follow-up. Intake of sugar, vegetables and fruit, and fibre were not associated with changes in CM risk factors in a statistically significant manner. Our findings suggest that a reduction in the consumption of total dietary fat and sodium may contribute to the prevention of excess body weight and hypertension in children and youth, and their cardiometabolic sequelae later in life.

Step Counts on Weekdays, Weekends, and During Physical Education of Navajo High School Students

BACKGROUND

Understanding the physical activity patterns of youth is important for the implementation and evaluation of programming and interventions designed to change behavior. To date, little is known about the objectively measured physical activity patterns of Native American youth. Therefore, the purpose of the study was to examine the step counts of Navajo youth during weekdays, weekend days, and physical education classes.

METHODS

Participants included 63 high school students (mean age = 15.14 ± 1.37 years). Youth wore a pedometer (Walk-4-Life 2505) for seven consecutive days. Means and standard deviations were calculated for weekdays, weekend days, and physical education.

RESULTS

Boys averaged 11,078 ± 4400 steps/weekday compared to 6493 ± 5651 on weekend days. Girls averaged 7567 ± 5614 on weekdays compared to 7589 ± 7712 on weekend days. Both boys (20 %) and girls (26 %) accumulated a large percentage of their weekday step counts from physical education classes.

CONCLUSIONS

Findings highlight the importance of additional physical activity opportunities in the community. Youth are falling well short of recommended levels of physical activity with physical education being an important source of physical activity.

Seasonal changes in objectively measured sedentary behavior and physical activity in Japanese primary school children

BACKGROUND

The recent prevalence of obesity in Japanese children is much higher compared to 1980. The present study compared daily sedentary behavior (SB) and physical activity (PA) between the school year and summer vacation in Japanese primary school children.

METHODS

Participants were 98 Japanese boys (8.9 ± 1.8 years at baseline) and 111 girls (9.1 ± 1.8 years). SB and PA were measured in May (school term) and July/August (summer vacation), 2011. SB and PA were assessed using a triaxial accelerometer (Active style Pro HJA-350IT, Omron Healthcare) for 7 consecutive days. The average number of minutes spent in SB (no more than 1.5 metabolic equivalents (METs)), light intensity activity (LPA; more than 1.5 to less than 3.0 METs) and moderate-to-vigorous physical activity (MVPA; 3.0 METs or more), and step counts were calculated for each individual. Moreover, the determinants/moderators of changes in SB and PA were examined.

RESULTS

Daily SB was significantly higher in the summer vacation than in the school year for both boys and girls (p < 0.05). Ambulatory and total LPA and MVPA, non-ambulatory LPA and step counts were lower in summer vacation in both genders (p < 0.001). Moreover, non-ambulatory MVPA was significantly lower in the summer vacation than in the school year for girls (p < 0.001). The decrease in non-ambulatory MVPA in boys and increase in SB in girls were significantly lower in those who participated in sports compared to those who did not (p < 0.040 or p < 0.033). The change in SB for boys was significantly associated with having a TV in the bedroom (p < 0.022).

CONCLUSIONS

These findings show that primary school children in Japan are less active in the summer vacation, as indicated by both higher SB and lower LPA and ambulatory MVPA in both genders. Moreover, the seasonal change in non-ambulatory MVPA for Japanese children was affected by gender. This study also suggests that sports participation and bedroom TV ownership may moderate seasonal changes in PA and SB. The results emphasize the need to take summer vacation into account when planning interventions aimed at decreasing SB or increasing PA in Japanese children.

Adherence to Canadian physical activity and sedentary behaviour guidelines among children 2 to 13 years of age

Active living is relevant for healthy child development and disease prevention. In 2011-2012 new Canadian Physical Activity and Sedentary Behaviour Guidelines were developed for children under four and 5-17 years of age. This cross-sectional study assessed children's adherence to the national guidelines, using a large sample of Alberta children ages 2-4 and 5-13 years in 2013. The proportions of children achieving the average daily duration of physical activity and screen time recommended were determined, and child and parental predictors of non-achievement were identified. Participants were 631 parent and child dyads. Data were collected by parental reports of physical activity and screen time during weekdays, and analysed using univariate and multivariate techniques (p < 0.05). Logistic regression models were used to examine factors associated with children's non-achievement of physical activity and screen time recommendations while adjusting for covariates. Sixty-two percent of children aged 2-4 and 26% of children aged 5-13 did not meet physical activity time recommendations, and 64% of children aged 2-4 and 23% of children aged 5-13 exceeded the maximum screen time recommendation. Several associations between parental age and education with non-achievement were observed but associations were not consistent across age groups or behaviours. Among preschoolers, those with middle-age parents were more likely to not achieve physical activity recommendations. Evidence of high non-achievement of the recommendations among children 2-4 years highlights the need for increased programming targeting preschool children. Further research is required to identify modifiable risk factors that may inform future health promotion efforts.

Physical Activity Patterns in University Students: Do They Follow the Public Health Guidelines?

Physical activity is associated with health. The aim of this study was (a) to access if Portuguese university students meet the public health recommendations for physical activity and (b) the effect of gender and day of the week on daily PA levels of university students. This observational cross-sectional study involved 126 (73 women) healthy Portuguese university students aged 18-23 years old. Participants wore the ActiGraph wGT3X-BT accelerometer for seven consecutive days. Number of steps, time spent sedentary and in light, moderate and vigorous physical activity were recorded. The two-way MANOVA revealed that gender (p-value = 0.001; η2 = 0.038; minimum effect) and day of the week (p-value = 0.001; η2 = 0.174; minimum effect) had significant main effects on the physical activity variables. It was shown that during weekdays, male students walked more steps (65.14%), spent less time sedentary (6.77%) and in light activities (3.11%) and spent more time in moderate (136.67%) and vigorous activity (171.29%) in comparison with weekend days (p < 0.05). The descriptive analysis revealed that female students walked more steps (51.18%) and spent more time in moderate (125.70%) and vigorous (124.16%) activities during weekdays than in weekend days (p < 0.05). Women students did not achieve the recommended 10,000 steps/day on average during weekdays and weekend days. Only male students achieved this recommendation during weekdays. In summary, this study showed a high incidence of sedentary time in university students, mainly on weekend days. New strategies must be adopted to promote physical activity in this population, focusing on the change of sedentary behaviour.

Within-Person Link between Depressed Affect and Moderate-to-Vigorous Physical Activity in Adolescence: An Intensive Longitudinal Approach

BACKGROUND

During adolescence, young women and men frequently show low physical activity and elevated depressed affect. This study aimed to examine the within-person link between moderate-to-vigorous physical activity (MVPA) and depressed affect in everyday life.

METHODS

Within an intensive longitudinal approach, adolescents (N = 72; 37% young women; M age = 17.36 years; age range: 12-26 years; mid-90% age range: 13-22 years) wore accelerometers to assess their daily MVPA and reported next-morning and same-evening depressed affect in diaries over eight consecutive days. The within-person link between MVPA and depressed affect on the next morning (time-lagged prediction) and the same evening (same-day link) was analyzed with mixed-effects models.

RESULTS

More-than-usual MVPA significantly predicted less next-morning depressed affect on weekdays in young women, to the extent that a 60-min increase in MVPA over the person mean significantly predicted 50 per cent lower next-morning depressed affect.

CONCLUSIONS

This study encourages the development of individually tailored physical activity interventions that could help adolescents enhance their daily amount of unstructured, self-initiated MVPA to reduce depressed affect. This approach may be particularly suitable for young women who have the highest risk for an inactive lifestyle and elevated depressed affect.

Gender and grade differences in objectively measured physical activity and sedentary behavior patterns among Japanese children and adolescents: a cross-sectional study

Background

Physical activity levels in childhood have decreased, making the promotion of children’s physical activity an important issue. The present study examined gender and grade differences in objectively measured sedentary behavior, physical activity, and physical activity guideline attainment among Japanese children and adolescents.

Methods

In total, 329 boys and 362 girls age 3–15 years completed the survey. School grade, gender, height, and weight were collected by questionnaires and physical activity objectively measured using an accelerometer (Lifecorder Suzuken Co.). Physical activity level (in MET) was classified as sedentary (<1.5), light (≥1.5 to <3), moderate (≥3 to <6), or vigorous (≥6). Continuous zero accelerometer counts for ≥20 min were censored and a valid accelerometry study required at least 3 days (2 weekdays and 1 weekend day) with > 600 min/day total wear time. Two-way analysis of covariance and logistic regression analyses, adjusted for weight status and accelerometer wear time, were used to examine gender and grade differences in physical activity variables and the likelihood of physical activity guideline attainment by gender and grade level.

Results

Participants were sedentary 441.4 (SD, 140.1) min/day or 53.7 % of the average daily accelerometer wear time of 811.2 (118.7) min, engaged in light physical activity 307.1 (70.0) min or 38.4 % of wear time, moderate physical activity 34.6 (14.8) min (4.3 %), vigorous physical activity 28.3 (19.1) min (3.6 %), and took 12462.6 (4452.5) steps/day. Boys were more physically active and took more steps/day than girls. Students in higher grades were less active than those in lower grades. Boys were significantly more likely to meet physical activity guidelines than girls (OR: 2.07, 95 % CI: 1.45–2.96). Preschoolers (6.66, 4.01–11.06), lower-grade elementary school students (17.11, 8.80–33.27), and higher-grade elementary school students (7.49, 4.71–11.92) were more likely to meet guidelines than junior high school students.

Conclusions

Boys and lower-grade students engaged in more physical activity and were more likely to attain guidelines than girls and higher-grade students. These findings highlight the need for effective and sustainable strategies to promote physical activity in Japanese school children.

Does School-Based Health Promotion Affect Physical Activity on Weekends? And, Does It Reach Those Students Most in Need of Health Promotion?

Objective

To determine whether a school-based health promotion program affects children’s weekend physical activity and whether this effect varies according to socioeconomic-status.

Methods

This was a quasi-experimental trial of school-based programs on physical activity levels implemented in disadvantaged neighborhoods in Alberta, Canada. In 2009 and 2011, 7 full days of pedometer data were collected from cross-sectional samples of grade 5 students (age 10–11 years) from 10 intervention schools in low-socioeconomic neighbourhoods and 20 comparison schools in middle-socioeconomic neighbourhoods. Multilevel models assessed differences in step-counts between intervention and comparison groups over-time by weight (objectively measured) and socioeconomic status subgroups.

Results

In 2009, children from intervention schools were less active on weekends relative to comparison schools (9212 vs. 11186 steps/day p<0.01). Two years later, daily step-counts on weekend days among children in low socioeconomic intervention schools increased such that they approximated those of children from middle socioeconomic comparison schools (12148 vs. 12121 steps/day p = 0.96). The relative difference in steps between intervention and comparison schools on weekends reduced from -21.4% to 0.2% following the intervention. The normalization of weekend step counts was similar for normal weight (–21.4% to +2.0%) and overweight (-19.1 to +3.9%) children, and was balanced across socioeconomic subgroups.

Conclusions

These data suggest that school-based health promotion is effective for reducing inequities in physical activity levels outside school hours. Investments in school-based health promotion lead to behavior modification beyond the school environment.

Trial Registration

ClinicalTrials.gov NCT01914185

The Intricacies of Children's Physical Activity

Understanding the physical activity patterns of youth is an essential step in preparing programming and interventions needed to change behavior. To date, little is known about the intricacies of youth physical activity across various physical activity segments (i.e. in school, out of school, recess, classroom physical activity, physical education, weekends, etc.). Therefore, the purpose of the study was to examine the physical activity patterns of elementary school children across various segments and during two seasons. A total of 287 fourth and fifth graders from the Southwest US wore the Yamax Digiwalker SW-200 pedometer for 7 consecutive days during the Fall and Spring seasons. Children were prompted to record their step counts when arriving and leaving school, before and after physical education and recess, as well as on the weekends. Means and standard deviations were calculated and ANOVAs and t tests were utilized to examine difference by sex, season, and segment. Youth were more active outside of school and on weekdays (p<0.05). Boys were generally more active than girls and all youth were more active during the milder Spring season. There is a clear need for Comprehensive School Physical Activity Programming and weekend physical activity opportunities. Furthermore, greater emphasis is needed on PE and across other activity segments for girls to increase their physical activity levels.

Outdoor time is associated with physical activity, sedentary time, and cardiorespiratory fitness in youth

OBJECTIVE

To determine whether time spent outdoors was associated with increased moderate-to-vigorous physical activity (MVPA) and related health benefits in youth.

STUDY DESIGN

We performed a cross-sectional study of 306 youth aged 13.6 ± 1.4 years. The exposure of interest was self-reported time spent outdoors after school, stratified into three categories: none, some, and most/all of the time. The main outcome of interest was accelerometer-derived MVPA (Actical: 1500 to >6500 counts/min). Secondary outcomes included sedentary behavior, cardiorespiratory fitness, overweight status, and blood pressure.

RESULTS

Among the 306 youth studied, those who reported spending most/all of their after-school time outdoors (n = 120) participated in more MVPA (61.0 ± 24.3 vs 39.9 ± 19.1 min/day; adjusted P < .001), were more likely to achieve the recommended minimum 60 min/day of MVPA (aOR 2.8; 95% CI, 1.3-6.4), spent less time in sedentary activities (539 ± 97 min/day vs 610 ± 146 min/day; adjusted P < .001), and had higher cardiorespiratory fitness (49 ± 5 vs 45 ± 6 mL/kg/min; adjusted P < .001) than youth who reported no time outdoors (n = 52). No differences in overweight/obesity or blood pressure were observed across the groups.

CONCLUSIONS

Time spent outdoors is positively associated with MVPA and cardiorespiratory fitness in youth and negatively associated with sedentary behavior. Experimental trials are needed to determine whether strategies designed to increase time spent outdoors exert a positive influence on physical activity and fitness levels in youth.

Objectively determined habitual physical activity in South African adolescents: the PAHL study

BACKGROUND

There is limited data on objectively determined habitual physical activity (PA) in 16-year old South African adolescents. The purpose of this study was to objectively determine the habitual PA of adolescents from the North West Province of South Africa by race and gender.

METHODS

Adolescents (137 girls, 89 boys) from the ongoing Physical Activity and Health Longitudinal Study (PAHL study), participated in the present study. Habitual PA was objectively recorded by means of the Actiheart® over a period of 7 days. Time spent in moderate-to-vigorous intensity physical activity (MVPA) was assessed.

RESULTS

Average MVPA for the study sample was 50.9 ± 40.3 minutes/day. Girls were significantly more active than boys expending more time in MVPA (61.13 ± 52.2 minutes/day; p < 0.05) than boys (35.0 ± 32.9 minutes/day). Although white adolescents spent more time in MVPA than black adolescents, there was no significant difference in MVPA between black (47.87 ± 39.6 minutes/day; p = 0.58) and white adolescents (59.5 ± 41.8 minutes/day).

CONCLUSION

Physical activity varies by both gender and race in adolescents from the North West Province of South Africa. Objectively determined data from our study indicates that girls habitually spend more time in MVPA per day than boys, and that white adolescents habitually engage in more MVPA than black adolescents. Seeing as the average MVPA per day for the entire study sample falls below the recommended daily average of 60 minutes/day, adolescents should be the foremost targets of interventions aimed at enhancing habitual PA.

School-based health promotion and physical activity during and after school hours

OBJECTIVES

Comprehensive school health (CSH) is a multifaceted approach to health promotion. A key objective of CSH is to foster positive health behaviors outside of school. This study examined the 2-year change in physical activity during and after school among students participating in a CSH intervention in Edmonton, Alberta, Canada.

METHODS

This was a quasi-experimental, pre-post trial with a parallel, nonequivalent control group. Intervention schools had to be located in socioeconomically disadvantaged neighborhoods. In the spring of 2009 and 2011, pedometer recordings (7 full days) and demographic data were collected from cross-sectional samples of fifth grade students from 10 intervention schools and 20 comparison schools. A total of 1157 students participated in the study. Analyses were adjusted for potential confounders and the clustered design.

RESULTS

Relative to 2009, children in 2011 were more active on schools days (1172 steps per day; P < .001) and on weekends (1450 steps per day; P < .001). However, the increase in mean steps between 2009 and 2011 was greater in CSH intervention schools than in comparison schools (school days: 1221 steps per day; P = .009; weekends: 2001 steps per day; P = .005). These increases remained significant after adjusting for gender and overweight status.

CONCLUSIONS

These findings provide evidence of the effectiveness of CSH to affect children's physical activity during and outside of school. Results of this study justify broader implementation of effective CSH interventions for physical activity promotion and obesity prevention in the long term.

Trajectories of objectively measured physical activity among secondary students in Canada in the context of a province-wide physical education policy: a longitudinal analysis

Lower levels of physical activity are associated with childhood obesity. School physical education (PE) policies have been identified as critical to improve child and adolescent physical activity levels but there has been little evaluation of such policies. In the province of Manitoba, Canada, the government implemented a mandatory PE policy in secondary schools designed to increase the daily physical activity levels of adolescents. The objective of this study was to examine the longitudinal changes in and the factors associated with the physical activity trajectories of adolescents in Manitoba during their tenure as secondary school students in the context of this school PE policy. The results found, despite the PE policy, a grade-related decline in the physical activity trajectories of adolescents; however, the decline in physical activity was attenuated among adolescents with low and moderate baseline physical activity compared to adolescents with high baseline physical activity and among adolescents who attended schools in neighbourhoods of low compared to high socioeconomic status. There are several possible explanations for these findings, including the influence of the PE policy on the PA patterns of adolescent subpopulations that tend to be at higher risk for inactivity in both childhood and adult life.

Objectively determined physical activity levels of primary school children in south-west Germany

Background

Only a small proportion of children and adolescents meet current recommendations of at least 60 min of moderate to vigorous physical activity (MVPA) daily. Most of the available data, however, relies on subjective reports; there is limited objective data on physical activity (PA) levels in German primary school children. The purpose of this study, therefore, was to accurately determine how much time children spend undertaking different intensities of PA and being sedentary during weekdays and weekend using objective assessment tools. Gender-specific and age-related differences were examined along with differences between normal weight and overweight/obese children.

Methods

Children’s height and weight were measured according to standard procedures and objective PA measurements were determined in a sub-cohort of 384 primary school children (20% of the whole cohort), participating in a large school-based intervention study in south-west Germany (n = 1947). Baseline data collection occurred on six consecutive days, including weekend days, using multi-sensor accelerometry (Actiheart, CamNtech Ltd., Cambridge UK). 318 children (7.1 ± 0.6 years, male: 50%, first grade: 51%) provided data for at least 3 days including one weekend day. According to the amount of energy expended, defined as metabolic equivalents (METs), different activity intensities were categorised as follows: sedentary < 1.5 METs; light = 1.5-3.0 METs; moderate = 3.0-6.0 METs, and vigorous > 6.0 METs.

Results

Average wear time was 1403 ± 94 min/day. Children spent 808 ± 97 min/day being sedentary; 497 ± 72 min/day in light; 128 ± 54 min/day in moderate, and 8 ± 10 min/day in vigorous intensity. 48% of children met the current MVPA guidelines. MVPA was significantly higher on weekdays compared to weekend days (144 ± 66 vs. 113 ± 66 min/day; p < 0.001). Furthermore, boys displayed higher MVPA levels compared to girls (164 ± 57 vs. 106 ± 50 min/day; p < 0.001).

Conclusion

Measured objectively, less than half of primary school children in the study met current PA recommendations, emphasising the necessity for early intervention to promote PA. Consistent with previous research, PA levels were higher in boys and during weekdays. These results indicate that PA levels of girls should especially be promoted in primary schools and that parents should be more involved in interventions to improve PA, particularly during weekends.