Relation between physical activity and energy expenditure in a representative sample of young children

Agreement of Two Physical Behaviour Monitors for Characterising Posture and Stepping in Children Aged 6-12 Years

All new physical behaviour measurement devices should be assessed for compatibility with previous devices. Agreement was assessed between the activPAL4TM and activPAL3TM physical behavior monitors within a laboratory and a multi-day free-living context. Healthy children aged 6-12 years performed standardised (sitting, standing, stepping) (12 min) and non-standardised (6 min) activities in a laboratory and a multi-day (median 3 days) free-living assessment whilst wearing both monitors. Agreement was assessed using Bland-Altman plots, sensitivity, and the positive predictive value (PPV). There were 15 children (7M/8F, 8.4 ± 1.8 years old) recruited. For the laboratory-based standardised activities, sitting time, stepping time, and fast walking/jogging step count were all within ±5% agreement. However, the activPAL4TM standing time was lower (-6.4%) and normal speed walking step count higher (+7.8%) than those of the activPAL3TM. For non-standardised activities, a higher step count was recorded by the activPAL4TM (+4.9%). The standardised activity sensitivity and PPV were all >90%, but the non-standardised activity values were lower. For free-living agreement, the standing time was lower (-7.6%) and step count higher (all steps + 2.2%, steps with cadence >100 step/min + 6.6%) for the activPAL4TM than the activPAL3TM. This study highlights differences in outcomes as determined by the activPAL4TM and activPAL3TM, which should be considered when comparing outcomes between studies.

Paths towards a healthier BMI among short and adequate sleepers: A pathway network analysis considering movement behaviors in low-income preschoolers

INTRODUCTION

Short sleep duration has been seen as a predictor of higher body mass index (BMI) in youth. Sleep duration varies substantially along early childhood, and the paths towards a healthier BMI, considering the other movement behaviors (physical activity-PA and screen time) are unexplored in preschoolers.

AIM

To construct a sleep-BMI model to capture the direct and indirect paths to intervening towards a healthier BMI, according to low-income preschoolers' compliance with the other movement behaviors.

METHODS

Two hundred and seventy two preschoolers (4.5 ± 0.0; 138 boys) participated in the study. Sleep and screen time (ST) were assessed in a face-to-face interview with primary caregivers. PA was assessed using accelerometer (wGT3X-BT). Preschoolers were categorized as compliant or not with sleep, screen time, total and moderate to vigorous PA recommendations. BMIz-score was calculated according to preschoolers' sex and age. All the assessed variables, besides sex and age were included in a Network Pathway Analysis (NPA) according to age as nodes.

RESULTS

At 3 years old, a direct and negative path between sleep-BMIz score was observed. At four and 5 years old, this relationship became positive. Further, girls were more compliant with sleep, ST and total PA recommendations. Total PA (TPA) showed the highest expected influence value in the general, 3 and 4 years old NPA.

CONCLUSION

The NPA analysis showed different directions for the relationship between sleep and BMIz score, according to age. Intervention strategies to a healthier BMI among preschoolers compliant or not with sleep recommendations should focus in increasing TPA.

Physical activity, sedentary time and nutritional status in Brazilian children with cerebral palsy

OBJECTIVE

This study had the purpose investigate the physical activity (PA) and sedentary time profile of children with cerebral palsy and its association with body composition.

METHODS

A cross-sectional study evaluated 53 children, between 2 and 10 years old, enrolled in three health services Recife-city, northeast of Brazil. Sedentary and PA were measured for a week using the ActiGraph GTX3 accelerometer. Body composition was assessed by anthropometry and an electrical bioimpedance device.

RESULTS

Time on PA was one hour longer among the mild/moderate CP compared to severe ones, but, sedentary time is similar. Dyskinetic children spent more time in PA, but also in sedentary activities (15.5 hours a day) than spastic ones (12.8). Stunting occurred in 15 (30%) of the sample, all children with stunting had severe impairment. Underweight occurred in 25% of the severe group and 11.8% in the mild/moderate group. Overweight affected 3% of the sample; no overweight children were in the severe group. Body fat% was inversely related to time spent in moderate to vigorous PA.

CONCLUSIONS

Children with CP spend more than a half of their daily time in sedentary activity. In contrast, children with mild to moderate CP spent twice as much time in moderate to vigorous PA and had a tendency (p = 0.07) to spend 50% more time in light PA. Moreover, time spent on moderate to vigorous activity was inversely related to fat mass.

Weekday and Weekend Physical Activity of Preschool Children in Relation to Selected Socioeconomic Indicators

Physical activity (PA) is as vital for improving the health of young children as it is positively associated with a broad range of psychological, cognitive, and cardio-metabolic outcomes. The aims of this study were to: (1) to assess the level of PA and meeting the WHO recommendations: moderate-to-vigorous physical activity (MVPA) and the number of steps in Polish preschool boys and girls on weekdays and on weekends; (2) to investigate the relationship between selected socioeconomic indicators (self-reported by parents) and PA, including meeting the WHO recommendation for daily MVPA and the number of steps on weekdays and on weekends among Polish preschoolers. Data were collected in the 2017/2018 school year. The study included a total of 522 boys and girls both aged between 5 and 6 years. The ActiGraph GT3X-BT tri-axial accelerometer was used to measure PA. Selected socioeconomic indicators as well as parental body weight and body height were self-reported by parents/caregivers using a questionnaire. In most of the PA indicators analyzed for girls (moderate, vigorous, total MVPA, and steps/day), the averages were higher during the week than during the weekend. Moreover, significantly more boys met the criteria of MVPA, both on weekdays and over the weekend (32.3% boys and 19.2% girls on weekdays and 31.1% boys and 18.1% girls on weekends). Additionally, more boys met the step recommendations, but only on weekends (15.5% boys and 6.6% girls). It was found that if there were two people in a household, there was an almost a three-fold greater chance (adj. OR = 2.94, p = 0.032) of meeting the MVPA criterion with an even stronger association (over fivefold greater chance) in meeting the step recommendation (adj. OR = 5.56, p = 0.033). The differences in the day schedule may potentially contribute with the level of PA in girls. Among the analyzed selected socioeconomic indicators, only the number of people in a household had a significant association on PA.

Movement behaviors in short versus adequate nocturnal sleepers: A compositional analysis of preschoolers

BACKGROUND

Accruing adequate daily amounts of time spent on movement behaviors (physical activity (PA), sedentary behavior (SB), and sleep) in childhood has been associated with positive short and long-term health outcomes. Nonetheless, how waking time is distributed across PA and SB among preschoolers who are short and adequate sleepers at night is unknown.

AIM

This study investigated: (1) if there are differences in a movement behaviors composition among adequate and short nocturnal sleepers; and (2) the association between preschoolers' time spent in PA, SB, and sleep among adequate and short nocturnal sleepers.

METHODS

A total of 270 preschoolers (132 boys; 3.97 ± 0.81 years old; 15.48 ± 1.62 kg/m² ) participated in this study. PA and SB were assessed using accelerometry (model wGT3X). Sleep duration was assessed through a parental-proxy interview, and preschoolers were stratified as short and adequate sleepers, according to attendance to international sleep duration guidelines. Compositional data analysis was used to explore the time-use patterns of behaviors among adequate and short sleepers.

RESULTS

Short sleepers spent 64 min less time asleep, accumulated 32 min in more sedentary time (p = .005, Cohen's d = 0.36, Bayes Factor: 6.17), and 24 min more in light PA (p = .0005, Cohen's d = 0.44, Bayes Factor: 46.37) compared to adequate sleepers.

CONCLUSIONS

Being a short sleeper was associated with greater time spent in SB and light PA during their waking hours. The health implications of movement behaviors composition among short sleep preschoolers should be further investigated.

The 24-h Movement Compositions in Weekday, Weekend Day or Four-Day Periods Differentially Associate with Fundamental Movement Skills

The aim of this study was to investigate the relationship between weekday, weekend day and four-day physical activity (PA) behaviours and fundamental movement skills (FMS) in British preschool children from a low socio-economic status background using compositional data analysis (CoDA). One hundred and eighty-five preschool children aged 3-4 years provided objectively assessed PA and sedentary behaviour (SB) data (GENEActiv accelerometer) and FMS (TGMD-2). The association of 24-h movement behaviours with FMS was explored using CoDA and isotemporal substitution (R Core Team, 3.6.1). When data were considered compositionally (SB, light PA (LPA), moderate and vigorous PA (MVPA)) and adjusted for age, BMI and sex, the weekday-derived composition predicted total motor competence (r² = 0.07), locomotor (r² = 0.08) and object control skills (r² = 0.09); the weekend day-derived composition predicted total motor competence (r² = 0.03) and object control skills (r² = 0.03), the 4-day-derived composition predicted total motor competence (r² = 0.07), locomotor (r² = 0.07) and object control skills (r² = 0.06) (all p < 0.05). Reallocation of 5 min of LPA at the expense of any behaviour was associated with significant improvements in total motor competence, locomotor and object control skills; for weekend-derived behaviours, MVPA was preferential. Considering movement behaviours over different time periods is required to better understand the effect of the 24-h movement composition on FMS in preschool children.

Associations between Movement Behaviours and Obesity Markers among Preschoolers Compliant and Non-Compliant with Sleep Duration: A Latent Profile Analysis

This study identifies physical activity (PA) and sedentary behaviour (SB) clusters in preschoolers compliant (C) or non-compliant (NC) with sleep recommendations; and associates these clusters with obesity markers. PA and SB were objectively assessed (Actigraph WGT3-X) in 272 preschoolers (4.4 ± 0.7 years old). Sleep duration was parent-reported, and preschoolers were classified as C (3-4 years old: 600-780 min/day; 5 years old: 540-660 min/day) or NC with sleep recommendations. Body mass index (BMI) and waist circumference (WC) were assessed according to international protocols. Moderate to vigorous physical activity (MVPA) and light physical activity (LPA) were categorized as low/high (<60 min/>60 min/day or <180 min/180 min/day, respectively). SB was defined according to mean values between clusters. Latent profile analysis was performed. Associations between the observed clusters and obesity markers were determined using linear regression (RStudio; 1.3.1073). Four cluster solutions for C and NC preschoolers were identified. A negative association between C/Low MVPA cluster and BMI, and a positive association between NC/Low MVPA and BMI (β = -0.8, 95%CI = -1.6;-0.1, and β = 0.9, 95%CI = 0.1;1.7, respectively) were observed. No association was seen for SB clusters. Adequate sleep duration may have a protective role for preschoolers' BMI, even if the children do not comply with MVPA recommendations.

Physical fitness percentiles of Polish children aged 4-7 years

The purpose of this study was to report sex- and age-specific physical fitness level in Polish children aged 4 to 7. 11.709 children participated in the study, including 5.684 girls and 6.025 boys aged 4 to 7 who attended kindergarten institutions throughout Poland. Physical fitness was assessed using four tests developed by Sekita including shuttle run 4 × 5 m with moving the block, standing long jump, throwing 1 kg medicine ball with two hands above the head and 20 m run. Percentile charts were developed separately for males and females using the LMS method. Boys showed higher physical fitness values than girls. In addition, an increase in the level of physical fitness was observed along with the age of the subjects. The developed reference values by age and sex in the field of physical fitness can be used for diagnostic purposes and assessing the level of physical fitness of preschool children. In addition, they can be helpful for healthcare professionals, parents and teachers to develop children's motor activation programs and monitor their physical fitness.

Adherence to 24-hour movement guidelines in low-income Brazilian preschoolers and associations with demographic correlates

BACKGROUND

The importance of movement behaviors for health is well known, although few studies have examined the adherence to movement guidelines in low-income preschoolers from a middle-income country, as Brazil. This study reports the proportion of preschoolers meeting the 24-hour movement guidelines and investigates its associations with demographic correlates in Brazilian low-income preschoolers.

METHODS

Two hundred and seventy preschoolers (132 boys, means age = 3.97 ± 0.80) provided physical activity (PA) data (Actigraph wGT3X). Sleep duration, screen time, and social correlates were parent-reported. Preschoolers were classified as compliant/not compliant with the 24-hour movement guidelines. Relationships between compliance with movement behaviors guidelines and demographic correlates were calculated using a network analysis (Mplus 8.0; Rstudio).

RESULTS

Preschoolers were active (273.52 ± 62.08 minutes/day of total PA), though moderate-to-vigorous physical activity (MVPA) time was below the guideline (58.68 ± 22.51 minutes/day); spent more than the recommended 60 minutes/day on screen time (169.91 ± 97.07 minutes/day); and slept less than 10 hours per night (9.44 ± 1.12 hours/day). Only 3% of the sample complied with the guidelines. PA showed the highest compliance (43%), compared to sleep duration (35%) and screen time (15%). Male sex was related to adherence to MVPA recommendations, while female sex, with adherence to total PA recommendations. Child's primary caregiver was the most important centrality indicator in the network.

CONCLUSION

Only 3% of the assessed preschoolers are compliant with the 24-hour movement behaviors guidelines. Strategies to promote adherence to movement behaviors among low-income preschoolers should consider child's primary caregivers to support movement behaviors.

Accelerometer-Based Physical Activity Levels Differ between Week and Weekend Days in British Preschool Children

Participation in physical activity (PA) is fundamental to children's future health. Studies examining the temporal pattern of PA between weekdays and weekends in British preschool children are lacking. Therefore, the aim of this study was to compare PA levels between week and weekend days for UK preschool children, using objective measurements. One hundred and eighty-five preschool children (99 boys, 86 girls, aged 4-5 years), from central England wore a triaxial accelerometer (GENEActiv) for 4 days to determine PA. The time (min) and percentage (%) of time spent in light, moderate and vigorous PA (MVPA) was determined using specific cut-points for counts per minute related to 3-5 year olds. Of the sample, none of the children met the UK recommended 180 min or more of PA per day. A significant difference (P < 0.05) was observed between the amount of time that preschool children spent in sedentary behaviours on weekdays (91.9%) compared to weekend days (96.9%). During weekdays and weekend days, 6.3% and 2.0% of time was spent in MVPA, respectively. Therefore, a substantial proportion of British preschool children's day is spent in sedentary behaviours, with less MVPA accrued during the weekend. Regular engagement during the weekdays provides opportunities to accrue PA, which may not be present on weekend days.

Development of healthy and sustainable food-based dietary guidelines for the Netherlands

Objective:

To derive healthy and sustainable food-based dietary guidelines (FBDG) for different target groups in the Netherlands and describe the process.

Design:

Optimised dietary patterns for children, adolescents, adults and the elderly were calculated using an optimisation model. Foods high in saturated and trans-fatty acids, salt and sugar, and low in dietary fibre, were excluded. The dietary patterns resembled the current food consumption as closely as possible, while simultaneously meeting recommendations for food groups, nutrients, maximum limits for foods with a high environmental impact, and within 85 % of the energy requirement. Recommended daily amounts of food groups were based on the optimised dietary patterns and expert judgement.

Setting:

The Netherlands.

Participants:

FBDG were derived for Dutch people with different ages, genders, activity levels and food preferences.

Results:

For most target groups the optimisation model provided dietary patterns that complied with all requirements. For some food groups, the optimised amounts varied largely between target groups. For consistent messages to consumers, the optimised dietary patterns were adjusted to uniform recommendations per target group. Recommendations were visualised in the Wheel of Five. The advice is to eat the recommended amounts of foods according to the Wheel of Five and limit consumption of other foods.

Conclusions:

Based on an optimisation model, scientific evidence, information on dietary patterns and expert knowledge, we derived FBDG for different target groups. The Wheel of Five is a key food-counselling model that can help Dutch consumers to make their diets healthier and more environmentally sustainable.

Kindergarten: Producer or Reducer of Inequality Regarding Physical Activity Levels of Preschool Children

Several studies have shown that children have sub-optimal physical activity levels. Since preschool children (4-6 years-old) spend most of their time awake in kindergarten on weekdays, physical activity level at kindergarten is crucial. The study examines preschool children's physical activity level at kindergarten. Preschool children's activity level at kindergarten is also investigated related to activity level at leisure, gender, and mothers' education level, income, and age. Two hundred and forty four children (125 boys and 119 girls) supplied valid accelerometer data, and mothers' education level, income, and age were measured using a questionnaire. One-way ANOVA and linear regression were utilized as statistical analyses. The results demonstrated that physical activity level during kindergarten is the main contributor to preschool children's physical activity level on weekdays. Furthermore, boys were more active than girls, and preschool children's physical activity level at both leisure and at kindergarten were not associated with mothers' age, education level, or income. However, a positive association was found between physical activity level at leisure and physical activity level at kindergarten, in which physical activity level at kindergarten increases when physical activity level at leisure increases. Physical activity level was also significantly different between kindergartens. The study indicated that kindergartens increase inequality according to physical activity level among preschool children-contributing to creating differences according to low-active and high-active children.

Subjectively and Objectively Assessed Behavioral, Social, and Physical Environmental Correlates of Sedentary Behavior in Preschoolers

OBJECTIVE

To investigate associations between preschoolers' objective leisure-time sedentary behavior and a comprehensive set of subjective and objective potential correlates of sedentary behavior across the behavioral, social, and physical environmental domains on both the family and community level.

STUDY DESIGN

In 3- to 6-year-old preschoolers (n = 738) from 52 preschools in Southern Germany, leisure time spent in sedentary behavior was assessed by accelerometry in 2008-2009. Family- and community-level potential correlates of sedentary behavior from different domains (behavioral, social, and physical environmental) were subjectively (ie, by parent-proxy report) and objectively (ie, by routine administrative data) assessed.

RESULTS

None of the objective social and physical environmental correlates showed associations with sedentary behavior. Leisure-time sedentary behavior decreased with greater levels of moderate-to-vigorous physical activity (both weekends and weekday afternoons), participation in organized sports, parental leisure-time physical activity, as well as greater parental traffic safety perceptions (weekends only).

CONCLUSIONS

Targeting multiple health behaviors at the same time (ie, physical activity and sedentary behavior) and focusing on the entire family (ie, preschoolers, parents, and potentially older siblings) might be useful opportunities to reduce sedentary behaviors in preschoolers.

Self-Reported Physical Activity is Not a Valid Method for Measuring Physical Activity in 15-Year-Old South African Boys and Girls

Physical activity plays an important role in the prevention of chronic lifestyle-related diseases. The development of valid instruments for the assessment of physical activity remains a challenge in field studies. The purpose of the present study was therefore to determine the level of agreement between physical activity objectively measured by the ActiHeart^® (Cambridge Neurotechnology Ltd, Cambridge, UK) device and subjectively reported physical activity by means of the International Physical Activity Questionnaire Short Form (IPAQ-SF) among adolescents attending schools in the Tlokwe Local Municipality, South Africa. A cross-sectional study design was used with a total of 63 boys and 45 girls aged 15 years who took part in the Physical Activity and Health Longitudinal Study (PHALS). Stature and weight were measured according to standard International Society for the Advancement of Kinanthropometry (ISAK) protocols. Objective physical activity (PA) was measured by a combined heart rate and accelerometer device (ActiHeart^®) for seven consecutive days. Time spent in moderate-to-vigorous intensity physical activity (MVPA) was assessed. Subjective physical activity was assessed with the self-reported IPAQ-SF. Objective PA indicated that 93% of the participants were inactive and only 6% were highly active. The IPAQ-SF showed that 24% were inactive, with 57% active. A non-significant correlation (r = 0.11; p = 0.29) between the ActiHeart^® measure of activity energy expenditure (AEE) and total physical activity (IPAQ-SF) was observed. The Bland–Altman plot showed no agreement between the two measurement instruments and also a variation in the level of equivalence. When Cohen’s kappa (κ) was run to determine the agreement between the two measurement instruments for estimated physical activity, a poor agreement (κ = 0.011, p < 0.005) between the two was found. The poor level of agreement between the objective measure of physical activity (ActiHeart^®) and the IPAQ-SF questionnaire should be interpreted cautiously. Future physical activity research using a combination of subjective and objective assessment methods in a large-scale cohort in adolescents is recommended.

Comparison of daily physical activity parameters using objective methods between overweight and normal-weight children

PURPOSE

The purpose of the present study was to determine if there were any differences in various aspects of physical activity such as energy expenditure, intensity, and type of activity between normal-weight and overweight boys.

METHODS

Children aged 9-12 years were recruited from 2 elementary schools located in different urban districts in Republic of Korea. The present study included 45 Korean boys, of which 19 were normal-weight and 26 were overweight. Daily physical activity was estimated over the same 1-week study period under free-living conditions using the doubly labeled water (DLW) method and a tri-axial accelerometer. Resting metabolic rate (RMR) was measured using the Douglas bag method and open-circuit indirect calorimetry. We calculated the physical activity level (PAL) as the total energy expenditure (TEE)/RMR.

RESULTS

PAL was not significantly different between the groups. In the accelerometer data, time spent in locomotive moderate-to-vigorous physical activity (MVPA) was significantly lower in overweight boys than in normal-weight subjects, whereas other variables including non-locomotive activity did not differ between groups. In addition, among all participants, time spent in total locomotive activity was significantly associated with PAL. Time spent in locomotive MVPA was significantly associated with PAL.

CONCLUSION

Overweight boys may be less physically active based on locomotive MVPA, which was positively related with PAL. Our findings suggest that the contribution of locomotive MVPA to the increase in PAL was relatively significant.

Effect of a pilot multi-component intervention on motor performance and metabolic risks in overweight/obese youth

This study evaluated the effect of a multi-component intervention on motor performance (MP) and metabolic risk markers (MRM) in overweight/obese youth. A secondary aim was to examine whether changes in MP are associated to changes in MRM. A 3-month multi-component intervention was performed, consisting of physical exercise sessions (twice/week;1h), nutritional education sessions (once/month), and parental support (twice/week). The sample included 35 volunteers (7-13 y.o), allocated to intervention (INT, n = 17) and control (CONT, n = 18) group. Variables were measured pre (T0) and post intervention (T1). Fasting blood samples were analyzed for MRM. MP tests included the measurement of health related physical fitness components and motor coordination performance (KTK battery). To assess food intake, a 24-hour recall diary was used. GLM-ANCOVA was performed. Standardized scores were calculated for the outcome variables, and multilinear regressions were applied to analyze associations between the key variables. INT group showed improvements in MP, glycolytic and hepatic profiles. After adjustments for MVPA, SB, total intake and maturational stage, negative associations between %ΔMP and %Δglycolytic (β = -.424; 95%CI:-0.343:-0.022), and %Δhepatic scores (β = -.382 95%CI:-0.001:-0.009) were observed. The intervention produced a moderate-to-high effect on the MP and some MRM. Changes in MP were inversely associated with changes in glycolytic and hepatic markers.

Examining Influences of Parenting Styles and Practices on Physical Activity and Sedentary Behaviors in Latino Children in the United States: Integrative Review

BACKGROUND

Research indicates that parents influence their children's physical activity (PA) and sedentary behaviors (SB) through their parenting styles and practices.

OBJECTIVE

The objectives of this paper were to evaluate existing research examining the associations between parenting styles, parenting practices, and PA and SB among Latino children aged between 2 and 12 years, highlight limitations of the existing research, and generate suggestions for future research.

METHODS

The method of this integrative review was informed by methods developed by Whittemore and Knafl, which allow for the inclusion of qualitative, quantitative, and mixed-methods studies. Using the Preferred Reporting Items for Systematic Reviews Meta-Analyses guidelines, five electronic academic databases (PubMed, SPORTDiscus, PsycINFO, PsycARTICLES, and CINAHL) were searched for peer-reviewed, full-text papers published in English. Of the 641 unique citations identified, 67 full-text papers were retrieved, and 16 were selected for review.

RESULTS

The majority of the 16 reviewed studies were conducted with predominantly Mexican American or Mexican immigrant samples, and only 1 study examined the association between parenting styles and Latino children's PA and SB. Most (n=15) reviewed studies assessed the influence of parenting practices on children's PA and SB, and they provide good evidence that parenting practices such as offering verbal encouragement, prompting the child to be physically active, providing logistic support, engaging and being involved in PA, monitoring, and offering reinforcement and rewards encourage, facilitate, or increase children's PA. The examined studies also provide evidence that parenting practices, such as setting rules and implementing PA restrictions due to safety concerns, weather, and using psychological control discourage, hinder, or decrease children's PA.

CONCLUSIONS

Because this review found a very small number of studies examining the relationship between parenting styles and Latino children's PA and SB, additional research is needed. Given that the majority of reviewed studies were conducted with predominantly Mexican American or Mexican immigrant samples, additional research examining parenting styles, parenting practices, and PA and SB among multiethnic Latino groups is needed to design interventions tailored to the needs of this ethnically diverse population group.

Evaluation of the wrist-worn ActiGraph wGT3x-BT for estimating activity energy expenditure in preschool children

BACKGROUND/OBJECTIVES

Easy-to-use and accurate methods to assess free-living activity energy expenditure (AEE) in preschool children are required. The aims of this study in healthy preschool children were to (a) evaluate the ability of the wrist-worn ActiGraph wGT3x-BT to predict free-living AEE and (b) assess wear compliance using a 7-day, 24-h protocol.

SUBJECTS/METHODS

Participants were 40 Swedish children (5.5±0.2 years) in the Mobile-based intervention intended to stop obesity in preschoolers (MINISTOP) obesity prevention trial. Total energy expenditure (TEE) was assessed using the doubly labeled water method during 14 days. AEE was calculated as (TEEx0.9) minus predicted basal metabolic rate. The ActiGraph accelerometer was worn on the wrist for 7 days and outputs used were mean of the daily and awake filtered vector magnitude (mean VM total and mean VM waking).

RESULTS

The ActiGraph was worn for 7 (n=34, 85%), 6 (n=4, 10%), 5 (n=1, 2.5%) and 4 (n=1, 2.5%) days (a valid day was ⩾600 awake minutes). Alone, mean VM total and mean VM waking were able to explain 14% (P=0.009) and 24% (P=0.001) of the variation in AEE, respectively. By incorporating fat and fat-free mass in the models 58% (mean VM total) and 62% (mean VM waking) in the variation of AEE was explained (P<0.001).

CONCLUSIONS

The wrist-worn ActiGraph wGT3x-BT in combination with body composition variables explained up to the 62% of the variation in AEE. Given the high wear compliance, the wrist-worn ActiGraph has the potential to provide useful information in studies where physical activity in preschool children is measured.

A review of early influences on physical activity and sedentary behaviors of preschool-age children in high-income countries

PURPOSE

Promoting physical activity (PA) is a key component of preventing and controlling childhood obesity. Despite well-documented benefits of PA, globally, rates of PA among young children have declined over the past decades, and most children are not accruing sufficient PA daily. Helping children develop the foundation for PA habits early in life is critical for the promotion of health in childhood and prevention of chronic diseases later in life, and will ultimately promote longer and healthier lives for individuals and the general population. The purpose of this review is to provide a synthesis of current evidence on influences on PA and sedentary behaviors of preschool-age children in high-income countries.

DESIGN AND METHODS

A systematic review of three databases was performed. Studies conducted in high-income countries and published from 2000 onward that addressed influences on PA and sedentary behaviors of preschool-age children were identified and reviewed. Additionally, reference lists of identified articles and relevant published reviews were reviewed. Studies that met the following inclusion criteria were considered: (a) sample included preschoolers (age ≤5 years); (b) PA and/or sedentary behaviors or factors associated with PA and/or sedentary behaviors was assessed; (c) published in English; (d) used either quantitative or qualitative methods; and (e) conducted in a high-income country. Data were extracted from selected studies to identify influences on PA and sedentary behaviors of preschool-age children and organized using the social-ecological model according to multiple levels of influence.

RESULTS

Results from included studies identify multiple factors that influence PA and sedentary behaviors of young children in high-income countries at the various levels of the social-ecological model including intrapersonal, interpersonal, environmental, organizational, and policy.

PRACTICE IMPLICATIONS

Given pediatric nurses' role as primary care providers, and their frequent and continued contact with parents and their children throughout childhood through well-child visits, immunization, and minor acute illnesses, they are well positioned to promote and support the development of early healthful PA habits of children starting in early childhood.

Association between objectively evaluated physical activity and sedentary behavior and screen time in primary school children

Background

Even when meeting guidelines for physical activity (PA), considerable sedentary time may be included. This study in primary school children investigated the relationships between objectively evaluated sedentary and PA times at different intensities using triaxial accelerometry that discriminated between ambulatory and non-ambulatory PA. The relationships between subjectively evaluated screen time (i.e. time spent viewing television and videos, playing electronic games, and using personal computers) and objectively evaluated sedentary and PA times were examined.

Methods

Objectively evaluated sedentary and PA times were assessed for 7 consecutive days using a triaxial accelerometer (Active style Pro: HJA-350IT) in 426 first to sixth grade girls and boys. Metabolic equivalents [METs] were used to categorize the minutes of sedentary time (≤1.5 METs), light PA (LPA, 1.6–2.9 METs), moderate-to-vigorous PA (MVPA,  ≥3.0 METs) and vigorous PA (VPA,  ≥6.0 METs). The physical activity level (PAL) was calculated using the mean MET value. Subjectively evaluated screen time behaviors were self-reported by participants and parents acting together. The associations between PA and sedentary and screen time variables were examined using partial correlation analyses.

Results

After adjustment for age, body weight and wearing time, objectively evaluated sedentary time correlated strongly with non-ambulatory and total LPA and PAL, moderately with ambulatory LPA, non-ambulatory or total MVPA, and weakly with ambulatory MVPA, ambulatory, non-ambulatory or total VPA. Subjectively evaluated screen time was not associated significantly with objectively evaluated sedentary and PA times or PAL. On average, each reduction of 30 min in daily sedentary time was associated with 6 or 23 min more of MVPA or LPA, respectively.

Conclusions

These findings show that higher daily sedentary time may be compensated mainly by lower LPA, while the association between sedentary time and MVPA was moderate. Therefore, improving MVPA and reducing sedentary time are important in primary school children.

Do the correlates of screen time and sedentary time differ in preschool children?

BACKGROUND

Preschool children can spend up to 12 h a day in sedentary time and few meet current recommendations for screen time. Little is known about ecological correlates that could be targeted to decrease specific versus total sedentary behaviour. This study examined whether the correlates of screen time and sedentary time differ in preschool boys and girls.

METHODS

Parents participating in the HAPPY Study in 2008/09 in Melbourne, Australia reported their child's usual screen time and potential individual, social and physical environment correlates. Children wore ActiGraph GT1M accelerometers for eight days to objectively assess sedentary time (<100 counts.min-1). Multivariable linear regression analyses were performed, stratified by sex and controlling for child age, preschool/childcare attendance and clustering by centre of recruitment. Correlates significantly associated with screen time or sedentary time in individual models (p < 0.05) were included in final combined models.

RESULTS

Children were sedentary for 301.1 (SD 34.1) minutes/day and spent 108.5 (SD 69.6) minutes/day in screen time. There were no sex differences in screen or sedentary time. In the final models, sleep duration was inversely associated with girls' sedentary time and boys' screen time. The only other consistent correlates for boys and girls were parental self-efficacy to limit screen time and screen time rules, which were inversely associated with screen time for both sexes. Parents reporting that they get bored watching their child play was inversely associated and maternal television viewing was positively associated with boys' screen time. Paternal age was positively associated with boys' sedentary time. Maternal ethnicity was inversely associated and paternal education, child preferences for sedentary behaviour, and parental concerns about child's physical activity and sedentary behaviour were positively associated with girls' screen time.

CONCLUSIONS

The modifiable correlates of total sedentary and screen time identified in this study could be targeted in interventions to reduce these behaviours. With correlates differing for screen and sedentary time, and between boys and girls, interventions may also benefit from including behaviour- and sex-specific strategies.

Learning about Activity and Understanding Nutrition for Child Health (LAUNCH): Rationale, design, and implementation of a randomized clinical trial of a family-based pediatric weight management program for preschoolers

Obesity affects nearly 2 million preschool age children in the United States and is not abating. However, research on interventions for already obese preschoolers is limited. To address this significant gap in the literature, we developed an intervention targeting obesity reduction in 2 to 5year olds, Learning about Activity and Understanding Nutrition for Child Health (LAUNCH). This paper describes the rationale, design, participant enrollment, and implementation of a 3-arm randomized, parallel-group clinical trial comparing LAUNCH to a motivational-interviewing intervention (MI) and standard care (STC), respectively. Whereas LAUNCH was designed as a skills based intervention, MI focused on addressing the guardian's motivation to make changes in diet and activity and providing tools to do so at the guardian's level of readiness to implement changes. Child body mass index z-score was the primary outcome, assessed at pretreatment, posttreatment (Month 6), and 6 and 12month follow-ups (Months 12 and 18). Mechanisms of weight change (e.g., dietary intake, physical activity) and environmental factors associated with weight (e.g., foods available in the home, caregiver diet) were also assessed. This study is unique because it is one of the few randomized controlled trials to examine a developmentally informed, clinic and home skills based behavioral family intervention for preschoolers who are already obese. Being obese during the preschool years increases the likelihood of remaining obese as an adult and is associated with serious health conditions; if this intervention is successful, it has the potential to change the health trajectories for young children with obesity.

Physical Activity During the Early Years: A Systematic Review of Correlates and Determinants

CONTEXT

Being physically active during the early years (age 0-6 years) is vital for healthy development. Identifying correlates and determinants of physical activity (PA) is crucial to guide effective interventions. This systematic review synthesized studies investigating potential correlates and determinants of PA during the early years, accounting for different types of PA assessment.

EVIDENCE ACQUISITION

Nine electronic databases were searched from inception year (1900) until September 2014; data were analyzed/interpreted in April 2015. The following inclusion criteria were used: written in English, published in peer-reviewed journals, participants not in statutory/school education, and an observational design investigating associations between an exposure/variable, and a quantitative measure of PA. Correlates/determinants of total, moderate to vigorous, and light PA were reported using an ecologic model.

EVIDENCE SYNTHESIS

Of 22,045 identified studies, 130 were included. All took place in high-income countries and few (6%) were of high quality. Correlates of total PA were sex (male, ++); parental PA (+); parental support (+); and time outdoors (+). Determinants of total PA were sex (+) and time spent playing with parents (+). The only correlate of moderate to vigorous PA was sex (male, ++). No determinants of moderate to vigorous or light PA were found. PA correlates/determinants were relatively consistent between objective and subjective PA measures.

CONCLUSIONS

Numerous studies investigated potential correlates and determinants of PA, but overall quality was low. A small number of demographic/biological and social/cultural factors were associated with PA. There is a need for high-quality studies exploring correlates/determinants across all domains of the ecologic model.

The extended Infant Feeding, Activity and Nutrition Trial (InFANT Extend) Program: a cluster-randomized controlled trial of an early intervention to prevent childhood obesity

BACKGROUND

Understanding how we can prevent childhood obesity in scalable and sustainable ways is imperative. Early RCT interventions focused on the first two years of life have shown promise however, differences in Body Mass Index between intervention and control groups diminish once the interventions cease. Innovative and cost-effective strategies seeking to continue to support parents to engender appropriate energy balance behaviours in young children need to be explored.

METHODS/DESIGN

The Infant Feeding Activity and Nutrition Trial (InFANT) Extend Program builds on the early outcomes of the Melbourne InFANT Program. This cluster randomized controlled trial will test the efficacy of an extended (33 versus 15 month) and enhanced (use of web-based materials, and Facebook® engagement), version of the original Melbourne InFANT Program intervention in a new cohort. Outcomes at 36 months of age will be compared against the control group.

DISCUSSION

This trial will provide important information regarding capacity and opportunities to maximize early childhood intervention effectiveness over the first three years of life. This study continues to build the evidence base regarding the design of cost-effective, scalable interventions to promote protective energy balance behaviors in early childhood, and in turn, promote improved child weight and health across the life course.

TRIAL REGISTRATION

ACTRN12611000386932. Registered 13 April 2011.

The effect of a cluster randomised control trial on objectively measured sedentary time and parental reports of time spent in sedentary activities in Belgian preschoolers: the ToyBox-study

BACKGROUND

In preschoolers, high levels of sedentary behaviour are associated with several adverse health outcomes. The purpose of this study is to report the effects of the ToyBox-intervention (a European 24-week cluster randomised controlled trial) on sedentary behaviour in preschoolers.

METHODS

In Belgium, 859 preschoolers from 27 kindergartens (15 intervention and 12 control) wore an accelerometer to objectively measure their sedentary time and 1715 parents/caregivers completed a questionnaire to assess sedentary activities in which preschoolers participate at home. Main outcomes were objectively measured sedentary time, time spent watching TV, using the computer and time spent in quiet play. Multilevel repeated measures analyses were conducted to take clustering into account. Intention to treat analysis was used to handle missing data.

RESULTS

A sample of 859 (29.5% of all contacted children) preschoolers (4.4 ± 0.6 years, 54.4% boys) provided valid accelerometer data at either baseline or follow-up and parents of 1715 (58.9% of all contacted children) preschoolers (4.4 ± 0.5 years, 52.5% boys) completed a questionnaire at either baseline or follow-up. No intervention effects were found on objectively and subjectively measured total sedentary time in the total sample. However, some effects on objectively and subjectively measured sedentary time were found in specific subgroups. Preschoolers from the intervention group from high SES kindergartens and preschoolers with high levels of sedentary time at baseline decreased their sedentary time, while preschoolers from the control group increased their sedentary time. Girls in the intervention group decreased their TV viewing time during weekend days (-5.83 min/day), while girls' &TV viewing in the control group increased (+4.15 min/day). In low SES kindergartens, a smaller increase for computer time during weekend days was found in preschoolers in intervention kindergartens (+6.06 min/day) than in control kindergartens (+12.49 min/day).

CONCLUSION

While some small positive effects were found in some sub-groups, the ToyBox-intervention had no effect on objectively and subjectively measured sedentary time in the total sample. A longer period to implement the intervention and a more active involvement of parents/caregivers might enhance intervention effects. The ToyBox-study is registered with the clinical trials registry clinicaltrials.gov, ID: NCT02116296.

Validity and practical utility of accelerometry for the measurement of in-hand physical activity in horses

Background

Accelerometers are valid, practical and reliable tools for the measurement of habitual physical activity (PA). Quantification of PA in horses is desirable for use in research and clinical settings. The objective of this study was to evaluate a triaxial accelerometer for objective measurement of PA in the horse by assessment of their practical utility and validity.

Horses were recruited to establish both the optimal site of accelerometer attachment and questionnaire designed to explore owner acceptance. Validity and cut-off values were obtained by assessing PA at various gaits. Validation study- 20 horses wore the accelerometer while being filmed for 10 min each of rest, walking and trotting and 5 mins of canter work. Practical utility study- five horses wore accelerometers on polls and withers for 18 h; compliance and relative data losses were quantified.

Results

Accelerometry output differed significantly between the four PA levels (P < 0•001) for both wither and poll placement. For withers placement, ROC analyses found optimal sensitivity and specificity at a cut-off of <47 counts per minute (cpm) for rest (sensitivity 99.5 %, specificity 100 %), 967–2424 cpm for trotting (sensitivity 96.7 %, specificity 100 %) and ≥2425 cpm for cantering (sensitivity 96.0 %, specificity 97.0 %). Attachment at the poll resulted in optimal sensitivity and specificity at a cut-off of <707 counts per minute (cpm) for rest (sensitivity 97.5 %, specificity 99.6 %), 1546–2609 cpm for trotting (sensitivity 90.33 %, specificity 79.25 %) and ≥2610 cpm for cantering (sensitivity 100 %, specificity 100 %) In terms of practical utility, accelerometry was well tolerated and owner acceptance high.

Conclusion

Accelerometry data correlated well with varying levels of in-hand equine activity. The use of accelerometers is a valid method for objective measurement of controlled PA in the horse.

Assessment of physical activity and sedentary behavior at preschools in Cape Town, South Africa

BACKGROUND

Overweight and obesity among young South African (SA) children have reached concerning levels. Preschool interventions to promote physical activity (PA) and reduce sedentary behavior (SB) could help curb these trends. However, research has not been conducted to assess these behaviors in SA preschools and how these might differ across income settings. This study aimed to (1) assess, by direct observation, PA and SB patterns of children in a range of preschool settings; (2) determine the influence of socioeconomic status on PA and SB; and (3) identify contextual and individual-level factors associated with PA.

METHODS

Eighty children (4-5 years old) from four low-income and four mid-/high-income preschools in Cape Town were observed using the Observational System for Recording Physical Activity in Children-Preschool Version.

RESULTS

Children spent 73% of their time engaged in SB. Low-income children spent 93% of their time indoors, compared to 79% among mid-/high-income children (p<0.001). Low-income children spent 11% of their time in moderate-to-vigorous PA (MVPA), compared to 8% among mid-/high-income children (p<0.05). Children across all settings were significantly more likely to engage in light PA (LPA) and MVPA if they were outside (relative risk ratio [RRR]=2.48 for LPA; RRR=6.95 for MVPA) and if their activity was adult-initiated (RRR=1.74 for LPA; RRR=1.66 for MVPA). Obese children were significantly less likely to do LPA (RRR=0.47); underweight children were significantly less likely to do LPA (RRR=0.63) and MVPA (RRR=0.26).

CONCLUSIONS

These findings provide information useful for the development of interventions to address PA and SB in SA preschool children.

An investigation into the minimum accelerometry wear time for reliable estimates of habitual physical activity and definition of a standard measurement day in pre-school children

The purpose of this study was to determine the number of hours and days of accelerometry data necessary to provide a reliable estimate of habitual physical activity in pre-school children. The impact of a weekend day on reliability estimates was also determined and standard measurement days were defined for weekend and weekdays.Accelerometry data were collected from 112 children (60 males, 52 females, mean (SD) 3.7 (0.7)yr) over 7 d. The Spearman-Brown Prophecy formula (S-B prophecy formula) was used to predict the number of days and hours of data required to achieve an intraclass correlation coefficient (ICC) of 0.7. The impact of including a weekend day was evaluated by comparing the reliability coefficient (r) for any 4 d of data with data for 4 d including one weekend day.Our observations indicate that 3 d of accelerometry monitoring, regardless of whether it includes a weekend day, for at least 7 h  d(-1) offers sufficient reliability to characterise total physical activity and sedentary behaviour of pre-school children. These findings offer an approach that addresses the underlying tension in epidemiologic surveillance studies between the need to maintain acceptable measurement rigour and retention of a representatively meaningful sample size.

A review of preschool children's physical activity and sedentary time using objective measures

CONTEXT

Identifying current physical activity levels and sedentary time of preschool children is important for informing government policy and community initiatives. This paper reviewed studies reporting on physical activity and time spent sedentary among preschool-aged children (2-5 years) using objective measures.

EVIDENCE ACQUISITION

Databases were searched for studies published up to and including April 2013 that reported on, or enabled the calculation of, the proportion of time preschool children spent sedentary and in light- and moderate to vigorous-intensity physical activity. A total of 40 publications met the inclusion criteria for physical activity and 31 met the inclusion criteria for sedentary time. Objective measures included ActiGraph, Actiwatch, Actical, Actiheart, and RT3 accelerometers, direct observation, and Quantum XL telemetry heart rate monitoring. Data were analyzed in May 2013.

EVIDENCE SYNTHESIS

Considerable variation in prevalence estimates existed. The proportion of time children spent sedentary ranged from 34% to 94%. The time spent in light-intensity physical activity and moderate to vigorous-intensity physical activity ranged from 4% to 33% and 2% to 41%, respectively.

CONCLUSIONS

The considerable variation of prevalence estimates makes it difficult to determine the "true" prevalence of physical activity and sedentary time in preschool children. Future research should aim to reduce inconsistencies in the employed methodologies to better understand preschoolers' physical activity levels and sedentary behavior.

Revision of Dietary Reference Intakes for energy in preschool-age children

BACKGROUND

Dietary Reference Intakes (DRI) for energy aim to balance energy expenditure at a level of physical activity consistent with health and support adequate growth in children. DRIs were derived from total energy expenditure (TEE) measured by using the doubly labeled water (DLW) method; however, the database was limited in the 3-5-y-old range.

OBJECTIVE

We reexamined the DRI for energy for preschool-age children.

DESIGN

Ninety-seven healthy, normal-weight, preschool-age children (mean ± SD age: 4.5 ± 0.9 y) completed a 7-d DLW protocol while wearing accelerometer and heart rate-monitoring devices.

RESULTS

Mean TEE and physical activity level (PAL) averaged 1159 ± 171 kcal/d and 1.34 ± 0.14, respectively. TEE predicted by DRI equations agreed with observed TEE (+34 kcal/d or 3%) if the sedentary PAL category was assumed but was overestimated by using the low active (+219 kcal/d or 19%), active (398 kcal/d or 34%), and very active (593 kcal/d or 51%) PAL categories. PAL categories were redefined on the basis of the narrower PAL range observed in preschoolers (range: 1.05-1.70) compared with older children and adults (range: 1.0-2.5). Sex-specific nonlinear regression models were newly developed to predict TEE from age, weight, height, and new PAL categories. The mean absolute error of TEE prediction equations was 0.00 ± 35 kcal/d or 0.1 ± 3%. Ancillary measures, such as total accelerometer counts and total daily steps, that were significantly correlated (P = 0.01-0.05) with TEE (r = 0.26-0.38), TEE per kilogram (r = 0.31-0.41), and PAL (r = 0.36-0.48) may assist in the classification of preschoolers into PAL categories.

CONCLUSIONS

Current DRIs for energy overestimate energy requirements of preschool-age children because of the erroneous classification of children into PAL categories. New TEE prediction equations that are based on DLW and appropriate PAL categories are recommended for preschool-age children. This trial was registered at clinicaltrials.gov as H12067.

Evaluation of Actiheart and a 7 d activity diary for estimating free-living total and activity energy expenditure using criterion methods in 1·5- and 3-year-old children

Accurate and easy-to-use methods to assess free-living energy expenditure in response to physical activity in young children are scarce. In the present study, we evaluated the capacity of (1) 4 d recordings obtained using the Actiheart (mean heart rate (mHR) and mean activity counts (mAC)) to provide assessments of total energy expenditure (TEE) and activity energy expenditure (AEE) and (2) a 7 d activity diary to provide assessments of physical activity levels (PAL) using three sets of metabolic equivalent (MET) values (PALTorun, PALAdolphand PALAinsworth) in forty-four and thirty-one healthy Swedish children aged 1·5 and 3 years, respectively. Reference TEE, PALrefand AEE were measured using criterion methods, i.e. the doubly labelled water method and indirect calorimetry. At 1·5 years of age, mHR explained 8 % (P= 0·006) of the variation in TEE above that explained by fat mass and fat-free mass. At 3 years of age, mHR and mAC explained 8 (P= 0·004) and 6 (P= 0·03) % of the variation in TEE and AEE, respectively, above that explained by fat mass and fat-free mass. At 1·5 and 3 years of age, average PALAinsworthvalues were 1·44 and 1·59, respectively, and not significantly different from PALrefvalues (1·39 and 1·61, respectively). By contrast, average PALTorun(1·5 and 3 years) and PALAdolph(3 years) values were lower (P< 0·05) than the corresponding PALrefvalues. In conclusion, at both ages, Actiheart recordings explained a small but significant fraction of free-living energy expenditure above that explained by body composition variables, and our activity diary produced mean PAL values in agreement with reference values when using MET values published by Ainsworth.

Associations between objectively measured physical activity and academic attainment in adolescents from a UK cohort

BACKGROUND

To test for cross-sectional (at age 11) and longitudinal associations between objectively measured free-living physical activity (PA) and academic attainment in adolescents.Method Data from 4755 participants (45% male) with valid measurement of PA (total volume and intensity) by accelerometry at age 11 from the Avon Longitudinal Study of Parents and Children (ALSPAC) was examined. Data linkage was performed with nationally administered school assessments in English, Maths and Science at ages 11, 13 and 16.

RESULTS

In unadjusted models, total volume of PA predicted decreased academic attainment. After controlling for total volume of PA, percentage of time spent in moderate-vigorous intensity PA (MVPA) predicted increased performance in English assessments in both sexes, taking into account confounding variables. In Maths at 16 years, percentage of time in MVPA predicted increased performance for males (standardised β=0.11, 95% CI 0.00 to 0.22) and females (β=0.08, 95% CI 0.00 to 0.16). For females the percentage of time spent in MVPA at 11 years predicted increased Science scores at 11 and 16 years (β=0.14 (95% CI 0.03 to 0.25) and 0.14 (0.07 to 0.21), respectively). The correction for regression dilution approximately doubled the standardised β coefficients.

CONCLUSIONS

Findings suggest a long-term positive impact of MVPA on academic attainment in adolescence.

Effect of a school-based active play intervention on sedentary time and physical activity in preschool children

Early childhood is a critical time for promoting physical activity. Few studies have investigated the effect of interventions in this population. The aim of this study was to investigate the effect of a school-based active play intervention on preschool children's sedentary time and physical activity. Preschool children were recruited from randomly selected preschools. Schools were randomly assigned to an intervention or comparison group. One teacher per intervention school received training from active play professionals in the delivery of a 6-week active play programme. Comparison schools continued their usual practice. Children wore a uni-axial accelerometer for 7 days at baseline, immediately after and at 6-month post-intervention. No significant intervention effects were observed for sedentary time or physical activity. However, sex and hours spent at school were significant predictors of physical activity. Children who spent fewer hours (half-day children) at school were significantly more active than their full-day counterparts. Physical activity during the intervention classes was high even though neither daily physical activity nor sedentary time changed. Notably children who spent more time at preschool were less active suggesting that preschool was not as conducive to physical activity engagement as other environments.

Energy expenditure compared to physical activity measured by accelerometry and self-report in adolescents: a validation study

Background

Physical inactivity is responsible for 5.3 million deaths annually worldwide. To measure physical activity energy expenditure, the doubly labeled water (DLW) method is the gold standard. However, questionnaires and accelerometry are more widely used. We compared physical activity measured by accelerometer and questionnaire against total (TEE) and physical activity energy expenditure (PAEE) estimated by DLW.

Methods

TEE, PAEE (TEE minus resting energy expenditure) and body composition were measured using the DLW technique in 25 adolescents (16 girls) aged 13 years living in Pelotas, Brazil. Physical activity was assessed using the Actigraph accelerometer and by self-report. Physical activity data from accelerometry and self-report were tested against energy expenditure data derived from the DLW method. Further, tests were done to assess the ability of moderate-to-vigorous intensity physical activity (MVPA) to predict variability in TEE and to what extent adjustment for fat and fat-free mass predicted the variability in TEE.

Results

TEE varied from 1,265 to 4,143 kcal/day. It was positively correlated with physical activity (counts) estimated by accelerometry (rho  = 0.57; p = 0.003) and with minutes per week of physical activity by questionnaire (rho  = 0.41; p = 0.04). An increase of 10 minutes per day in moderate-to-vigorous intensity physical activity (MVPA) relates to an increase in TEE of 141 kcal/day. PAEE was positively correlated with accelerometry (rho  = 0.64; p = 0.007), but not with minutes per week of physical activity estimated by questionnaire (rho  = 0.30; p = 0.15). Physical activity by accelerometry explained 31% of the vssariability in TEE. By incorporating fat and fat-free mass in the model, we were able to explain 58% of the variability in TEE.

Conclusion

Objectively measured physical activity significantly contributes to the explained variance in both TEE and PAEE in Brazilian youth. Independently, body composition also explains variance in TEE, and should ideally be taken into account when using accelerometry to predict energy expenditure values.

Validation of the TracmorD triaxial accelerometer to assess physical activity in preschool children

OBJECTIVES

To assess validity evidence of TracmorD to determine energy used for physical activity in 3-4-year-old children.

DESIGN AND METHODS

Participants were randomly selected from GECKO Drenthe cohort (n = 30, age 3.4 ± 0.3 years). Total energy expenditure (TEE) was measured using the doubly labeled water method. Sleeping metabolic rate (SMR) was measured by indirect calorimetry (Deltatrac). TEE and SMR were used to calculate physical activity level (PAL) and activity energy expenditure (AEE). Physical activity was monitored using a DirectLife triaxial accelerometer, TracmorD with activity counts per minute (ACM) and activity counts per day (ACD) as outcome measures.

RESULTS

The best predictor for PAL was ACM with gender and weight, the best predictor for AEE was ACM alone (backward regression, R(2) = 0.50, P = 0.010 and R2 = 0.31, P = 0.011, respectively). With ACD, the prediction model for PAL included ACD, height, gender, and sleep duration (R2 = 0.48, P = 0.033), the prediction model for AEE included ACD, gender and sleep duration (R2 = 0.39, P = 0.042). The accelerometer was worn for 5 days, but 3 days did not give a different estimated PAL.

CONCLUSION

TracmorD provides moderate-to-strong validity evidence that supports its use to evaluate energy used for physical activity in 3-4-year-old children.

Cross-sectional time series and multivariate adaptive regression splines models using accelerometry and heart rate predict energy expenditure of preschoolers

Prediction equations of energy expenditure (EE) using accelerometers and miniaturized heart rate (HR) monitors have been developed in older children and adults but not in preschool-aged children. Because the relationships between accelerometer counts (ACs), HR, and EE are confounded by growth and maturation, age-specific EE prediction equations are required. We used advanced technology (fast-response room calorimetry, Actiheart and Actigraph accelerometers, and miniaturized HR monitors) and sophisticated mathematical modeling [cross-sectional time series (CSTS) and multivariate adaptive regression splines (MARS)] to develop models for the prediction of minute-by-minute EE in 69 preschool-aged children. CSTS and MARS models were developed by using participant characteristics (gender, age, weight, height), Actiheart (HR+AC_x) or ActiGraph parameters (AC_x, AC_y, AC_z, steps, posture) [x, y, and z represent the directional axes of the accelerometers], and their significant 1- and 2-min lag and lead values, and significant interactions. Relative to EE measured by calorimetry, mean percentage errors predicting awake EE (-1.1 ± 8.7%, 0.3 ± 6.9%, and -0.2 ± 6.9%) with CSTS models were slightly higher than with MARS models (-0.7 ± 6.0%, 0.3 ± 4.8%, and -0.6 ± 4.6%) for Actiheart, ActiGraph, and ActiGraph+HR devices, respectively. Predicted awake EE values were within ±10% for 81-87% of individuals for CSTS models and for 91-98% of individuals for MARS models. Concordance correlation coefficients were 0.936, 0.931, and 0.943 for CSTS EE models and 0.946, 0.948, and 0.940 for MARS EE models for Actiheart, ActiGraph, and ActiGraph+HR devices, respectively. CSTS and MARS models should prove useful in capturing the complex dynamics of EE and movement that are characteristic of preschool-aged children.

Effect of a family focused active play intervention on sedentary time and physical activity in preschool children

Background

Early childhood provides a window of opportunity for the promotion of physical activity. Given the limited effectiveness of interventions to date, new approaches are needed. Socio-ecological models suggest that involving parents as intervention targets may be effective in fostering healthier lifestyles in children. This study describes the effectiveness of a family-focused ‘Active Play’ intervention in decreasing sedentary time and increasing total physical activity in preschool children.

Method

Seventy-seven families were recruited from 8 randomly selected SureStart children’s centres in the North West of England. Centres were randomly assigned to either an intervention (n = 4) or a comparison group (n = 4). Parents and children in the intervention group received a 10-week active play programme delivered by trained active play professionals; this included an activity and educational component. Families in the comparison group were asked to maintain their usual routine. Each participating parent and child wore a uni-axial accelerometer for 7 days at baseline and post-test. Week and weekend day sedentary time and total physical activity adjusted for child- and home- level covariates were analysed using multilevel analyses.

Results

Significant intervention effects were observed for sedentary time and physical activity for both week and weekend days. Children in the intervention group engaged in 1.5% and 4.3% less sedentary time during week and weekend days, respectively and 4.5% and 13.1% more physical activity during week and weekend days, respectively than children in the comparison group. Parent’s participation in sport and their physical activity levels, child’s sex, availability of media in the home and attendance at organised activities were significant predictors of sedentary time and physical activity in this age group.

Conclusion

A 10-week family focused active play intervention produced positive changes in sedentary time and total physical activity levels in preschool children. Specific covariates were identified as having a significant effect on the outcome measures. Moreover, children whose parents were active engaged in less sedentary time and more physical activity suggesting that parent’s activity habits are mediators of physical activity engagement in this age group.

Child, family and environmental correlates of children's motor skill proficiency

OBJECTIVES

To identify factors associated with children's motor skills.

DESIGN

Cross-sectional.

METHODS

Australian preschool-aged children were recruited in 2009 as part of a larger study. Parent proxy-report of child factors (age, sex, parent perception of child skill, participation in unstructured and structured activity), self-report of parent factors (confidence in their own skills to support child's activity, parent-child physical activity interaction, parent physical activity) and perceived environmental factors (play space visits, equipment at home) were collected. Moderate to vigorous physical activity (MVPA) (ActiGraph GT1M accelerometer) and motor skills (Test of Gross Motor Development-2) were also assessed. After age adjustment, variables were checked for association with raw object control and locomotor scores. Variables with associations of p<0.20 were entered into two multiple regression models with locomotor/object control as respective outcome variables.

RESULTS

Motor skills were assessed for 76 children (42 female), mean [SD] age=4.1 [0.68]; 71 completed parent proxy-report and 53 had valid MVPA data. Child age, swimming lessons, and home equipment were positively associated explaining 20% of locomotor skill variance, but only age was significant (β=0.36, p=0.002). Child age and sex, unstructured activity participation, MVPA%, parent confidence, home equipment (all positively associated), and dance participation (inversely associated) explained 32% object control variance. But only age (β=0.67, p<0.0001), MVPA% (β=0.37, p=0.038) and no dance (β=-0.34, p=0.028) were significant.

CONCLUSION

Motor skill correlates differ according to skill category and are context specific with child level correlates appearing more important.

The relationship between objectively measured physical activity, sedentary time, and vascular health in children

BACKGROUND

Physical activity (PA) is beneficially associated with arterial compliance in adults; however, whether this association persists in children is unclear. We examined the cross-sectional relationship of PA and sedentary time with arterial compliance in children.

METHODS

Large and small artery compliance was determined by diastolic pulse contour analysis in 102 children aged 8-11 years (43 boys). We used accelerometers and age-specific cut points to classify activity as sedentary, light, or moderate-to-vigorous (MVPA). We also categorized MVPA according to bout length (0-5, 5-10, 10-20, and ≥20 min). Hierarchical linear regression examined: (i) the contribution of activity to large and small artery compliance (controlling for body surface area, systolic blood pressure, and body mass index (BMI)) and (ii) whether bouted MVPA was associated with arterial compliance independent of total MVPA.

RESULTS

Activity variables did not explain any additional variance in large artery compliance beyond that captured by body surface area, BMI, and systolic blood pressure (P = 0.118 to P = 0.990). Light activity and MVPA explained an additional 5.8% (P = 0.003) and 2.7% (P = 0.043) of the variance in small artery compliance. MVPA accumulated in bouts was not significantly associated with small artery compliance after controlling for the total volume of MVPA (P = 0.784 to P = 0.923).

CONCLUSIONS

Objectively measured PA is associated with small, but not large artery compliance in children aged 8-11 years. Future research should explore the influence of bout frequency and the effect of a PA.intervention on arterial compliance.

Physical activity promotion in the preschool years: a critical period to intervene

The primary aim of this paper is to provide a rationale for the necessity of intervening with a physical activity intervention in the preschool years and why the daycare environment is amenable to such intervention. We also review the prevalence of physical activity, sedentary behaviour and obesity in the preschool population and the impact that these lifestyle behaviours and conditions have on the health of preschool aged children, as secondary objectives. Moreover we discuss implications for intervention and research using a "lessons learned" model based on our research team's experience of conducting a randomized controlled trial aimed at increasing physical activity, reducing sedentary behaviour and improving motor skill development and body composition in preschoolers. Lastly, we make conclusions based on the literature and highlight issues and directions that need to be addressed in future research in order to maximize health promotion and chronic disease prevention in the pediatric population.

Accelerometer-derived physical activity levels of preschoolers: a meta-analysis

OBJECTIVES

This study synthesized the published estimates of daily moderate-to-vigorous physical activity (MVPAd(-1)) of preschooler-age children (3-5 years).

DESIGN

Meta-analysis of previously published studies reporting accelerometer-derived estimates of daily MVPA of preschoolers.

METHODS

A comprehensive literature review was conducted to identify studies published by March 2010 that reported daily minutes of accelerometer-derived MVPA in preschool-age children (3-5 years). Random effects point estimates and 95% confidence intervals (95% CIs) were calculated based on study weighted means and standard deviations of raw accelerometer counts per minute (cpm) and reported minutes of MVPA and/or percentage of time spent in MVPAd(-1).

RESULTS

29 articles representing 6309 preschoolers were included. Overall, preschoolers engaged in 42.8 min (95% CI 28.9-56.8) of MVPAd(-1), and 54.4 min (95% CI 29.9-78.9) and 45.4 min (95% CI 25.2-65.6) for boys and girls separately. This translated into approximately 5.5% (95% CI 3.7-7.2%) of time spent in MVPAd(-1), and 7.1% (95% CI 3.9-10.3%) for boys and 6.3% (95% CI 3.9-8.7%) for girls. Studies (76%) using ActiGraph accelerometers reported an average of 714 cpm (95% CI 678-751), with boys and girls having 783 cpm (95% CI 753-813) and 696 cpm (95% CI 665-727), respectively.

CONCLUSIONS

Interpretation of accelerometer-derived MVPA is confounded by differences in cutpoints applied within a study. Great care, therefore, should be taken when interpreting the activity levels of preschoolers to inform policy decisions, such as the development of physical activity guidelines. Hence, considerable attention is required to unify accelerometer-derived MVPA so that unbiased comparisons across studies can be made.

MVPA is associated with lower weight gain in 8-10 year old children: a prospective study with 1 year follow-up

BACKGROUND

Studies relating physical activity (PA) to weight gain in children have produced mixed results, although there is some evidence for stronger associations with more intense physical activities. The present study tested the hypothesis that weight gain over one year in 8-10 year olds would be more strongly predicted by moderate and vigorous physical activity (MVPA) than total physical activity (total PA) or sedentary behaviour.

METHODOLOGY

Participants were 280 children taking part in the Physical Exercise and Appetite in Children Study (PEACHES). Weight status was assessed using body mass index (BMI), fat mass index (FMI), and waist circumference (WC) in school Year 4 (baseline; age 8.7 yrs) and Year 5 (follow-up; age 9.7 yrs). Physical activity was measured at baseline using the Actigraph GT1M accelerometer to assess total PA (mean accelerometers counts per minute), MVPA; ≥ 4000 counts per minute) and sedentary time (<100 counts per minute).

PRINCIPAL FINDINGS

After adjustment for baseline BMI, SES, sex and ethnicity, MVPA was significantly associated with follow-up BMI (adjusted β  = -0.07; p = 0.002). This association was independent of total PA or sedentary time. Similar results were observed for FMI; again MVPA was significantly associated with follow up FMI (β = -0.16; p = 0.001) independent of total PA or sedentary time. The pattern was similar for WC (β = -0.07), but the association between MVPA and WC did not reach significance at p = 0.06.

CONCLUSION

The results of this study strongly support promotion of MVPA in children.

Validity, practical utility and reliability of Actigraph accelerometry for the measurement of habitual physical activity in dogs

OBJECTIVES

To test the validity, practical utility, and reliability of the Actigraph GT3-X accelerometer for measurement of habitual physical activity in pet dogs.

METHODS

In the validation study, 30 dogs wore the accelerometer for 1 day while being filmed. Accelerometer and film were synchronised and 10-minute periods of the filmed records were extracted with dogs in continuous periods of sedentary behaviour, light intensity physical activity indoors, light to moderate intensity physical activity outdoors and vigorous physical activity outdoors. For the practical utility and reliability studies, 20 dogs wore the GT3-X accelerometers for 1 week: practical utility was quantified as data loss and was also assessed by owner questionnaire; reliability was determined by 2 to 7 days of monitoring using the Spearman-Brown prophecy formula.

RESULTS

In the validation study, accelerometry output differed significantly between activity intensities (Friedman test, P<0·01). In the practical utility study, no data were lost from any dogs and dog owners reported that accelerometry was well tolerated. Reliability of accelerometry output was high: for 3 days of wear, it was 91% [95% confidence interval (CI) 82 to 96] and for 7 days of wear, it was 94% (CI 88 to 97).

CLINICAL SIGNIFICANCE

The GT3-X accelerometer is valid, practical and reliable for the measurement of habitual physical activity in dogs.

[Physical activity level among children and adolescents orphaned by AIDS]

OBJECTIVE

To estimate the level of physical activity among children and adolescents orphaned by AIDS according to socio-demographic and orphanhood-related characteristics.

METHODS

A population-based study was carried out with 235 children and adolescents aged 7 to 14 years in the municipality of São Paulo, SP, in 2007. Children were classified as active and inactive. The cut-off point established was 300 minutes of weekly physical activity. All variables were compared between both groups and sexes.

RESULTS

An overall prevalence of 42% of inactivity was found. Active commuting and child's play were the main physical activities for most of the children and adolescents. As for physical activity level, a significant difference was observed between sexes (p < 0.001). Boys were more active and played outdoors more than girls.

CONCLUSIONS

There is a high prevalence of physical inactivity among children and adolescents orphaned by AIDS, especially girls.