Prediction of energy expenditure and physical activity in preschoolers

Twenty-four-hour movement behaviours and fundamental movement skills in preschool children: A compositional and isotemporal substitution analysis

Studies that have analysed the association between the different movement behaviours and fundamental movement skills (FMS) have considered it in an independent manner, disregarding the compositional nature of 24-h movement behaviours (24-h MB). The aim of this study was to investigate the relationship between the 24-h MB and FMS in preschoolers using a compositional data analysis . Two hundred and four preschoolers (4.5 ± 0.8 years old; 101 boys) provided objectively assessed physical activity (PA) and sedentary behaviour (SB) data (Actigraph wGT3X), and FMS (TGMD-2). Sleep duration (SD) was reported by parents. Association of daily composition of movement behaviours with FMS was explored using compositional analysis and isotemporal substitution (R Core Team, 3.6.1). When considered as a 24-h MB composition (PA, SB and SD), adjusted for age, BMI and sex, the composition predicted locomotor (r² = 0.31), object control (r² = 0.19), and total motor score (r² = 0.35), respectively (all P < 0.001). Reallocation of time from light to moderate-to-vigorous PA was associated with greatest positive changes in total motor score. Achieving adequate balance between movement behaviours over the 24-h period, and its relationship with locomotor and object control skills should be considered and further investigated in early childhood.

Feasibility of the Energy Expenditure Prediction for Athletes and Non-Athletes from Ankle-Mounted Accelerometer and Heart Rate Monitor

Due to the nature of micro-electromechanical systems, the vector magnitude (VM) activity of accelerometers varies depending on the wearing position and does not identify different levels of physical fitness. Without an appropriate energy expenditure (EE) estimation equation, bias can occur in the estimated values. We aimed to amend the EE estimation equation using heart rate reserve (HRR) parameters as the correction factor, which could be applied to athletes and non-athletes who primarily use ankle-mounted devices. Indirect calorimetry was used as the criterion measure with an accelerometer (ankle-mounted) equipped with a heart rate monitor to synchronously measure the EE of 120 healthy adults on a treadmill in four groups. Compared with ankle-mounted accelerometer outputs, when the traditional equation was modified using linear regression by combining VM with body weight and/or HRR parameters (modified models: Model A, without HRR; Model B, with HRR), both Model A (r: 0.931 to 0.972; ICC: 0.913 to 0.954) and Model B (r: 0.933 to 0.975; ICC: 0.930 to 0.959) showed the valid and reliable predictive ability for the four groups. With respect to the simplest and most reasonable mode, Model A seems to be a good choice for predicting EE when using an ankle-mounted device.

Physical Activity Coparticipation Among Parent-Young-Child Dyads

PURPOSE

This study examined patterns of physical activity coparticipation among parent-child (2-5 y) dyads.

METHOD

The dyads (N = 47; 51% mother-child) each wore a Bluetooth-enabled accelerometer for 8 days to measure physical activity and physical activity coparticipation. The parents completed demographic and self-reported family physical activity questionnaires.

RESULTS

The parent-child dyads spent 145 (79) minutes per day in-proximity according to the Bluetooth-enabled accelerometers. The majority (90%) of parent-child in-proximity time was spent with the parent and child engaged in some combination of sedentary or light activities. Child light, moderate, and vigorous physical activity was not associated with parent light (P = .12) or moderate to vigorous physical activity (P = .45), but was positively associated with parent-child in-proximity active minutes (light, moderate, and vigorous) (P < .01). Children in the highest tertile of parent-child physical activity coparticipation engaged in more daily moderate to vigorous physical activity compared with children in the lowest tertile (72.7 vs 50.3 min). There was a positive, statistically significant association between self-reported and objective measures of physical activity coparticipation (r = .47, P = .001).

CONCLUSION

Children who engaged in the most physical activity with their parent had the highest moderate to vigorous physical activity. Future studies should continue to provide contextual information about how parents and children spend their time together to improve family-based physical activity interventions.

Laboratory-based and free-living algorithms for energy expenditure estimation in preschool children: A free-living evaluation

Machine learning models to predict energy expenditure (EE) from accelerometer data have traditionally been trained on data from laboratory-based activity trials. However, accuracy is typically attenuated when implemented in free-living scenarios. Currently, no studies involving preschool children have evaluated the accuracy of EE prediction models trained on laboratory (LAB) under free-living conditions.

Physical activity level of kindergarten staff working with toddlers and older children in Norway

BACKGROUND:

Research suggests that one-third of Norwegian adults satisfy national health recommendations for physical activity, but little knowledge exists regarding activity levels in different occupations.

OBJECTIVES:

This study investigates the level at which kindergarten staff fulfil these health recommendations, and examines differences in physical activity levels of staff working mainly with toddlers (1–3 years) and older children (4–6 years). The study also investigates physical activity level during working time and leisure time.

METHODS:

Physical activity levels among 43 kindergarten staff members were measured utilizing accelerometers and questionnaires.

RESULTS:

The results demonstrate that 86% of kindergarten staff satisfy the health recommendations for physical activity. Moreover, kindergarten staff working with older children were significantly more physically active than staff working with toddlers.

CONCLUSIONS:

Physical activity level during working time was found to be of major significance for fulfilling the health recommendations among kindergarten staff working with toddlers.

Who benefits from the intervention? Correlates of successful BMI reduction in the Texas Childhood Obesity Demonstration Project (TX-CORD)

BACKGROUND

Many childhood obesity intervention studies report mean outcomes but do not explore the variation in responses and the characteristics of those who respond well.

OBJECTIVE

To identify child and family characteristics associated with improvement in the primary outcome, %BMI_p95 , of the Texas Childhood Obesity Research Demonstration project (TX-CORD).

METHODS

The 12-month TX-CORD secondary prevention study randomized 549 children, ages 2 to 12 years, with BMI ≥85th percentile to the intensive intervention vs. the comparison program, with measurements at baseline, 3-, and 12-months. A growth mixture model was used to identify mutually exclusive latent %BMI_p95 trajectories. Latent class regression tested associations between baseline characteristics and latent class membership.

RESULTS

A 2-class solution emerged after accounting for the effect of intervention randomization. Latent Class 1 participants (86% of sample) were characterized by mild-to-moderate obesity and demonstrated a significantly greater response to the intensive intervention between 0 and 3 months (slope-on-group = -0.931, p = 0.03). A rebound between 3 and 12 months was not significantly different between arms. Latent Class 2 participants (14%), who had severe obesity, demonstrated no difference in response between intervention groups. Characteristics associated with Class 1 membership included younger age (2-5 years vs. 6-12 years: OR 3.70, p = .035) and lower maternal BMI category (< 35 kg/m² vs. ≥ 35 kg/m² : OR 7.14, p < .0001).

CONCLUSIONS

The optimal target population for the intensive intervention are children who have milder obesity, are younger, and do not have a mother with severe obesity. Children with severe obesity may require different approaches.

Correlates of sedentary time in young children: A systematic review

Background: Young children appear to spend large portions of their waking time being sedentary. Understanding the correlates of sedentary time would assist in developing effective interventions among young children. The purpose of this systematic review was to summarize the current literature on the correlates of objectively measured sedentary time in young children aged 1-5.99y. Methods: This review was registered with PROSPERO (registration no. CRD42017081374) and aligned with the PRISMA Statement for systematic reviews. Five electronic databases (MEDline, CINAHL Complete, PsycINFO, SportDiscus, Scopus) were searched up to October 26, 2017 for studies investigating correlates of sedentary time measured using objective devices. A semiquantitative approach was used to synthesize data. Results: Forty-five studies were retrieved comprising 13,430 participants, and 84 correlates of sedentary time in young children were evaluated. The associations between sex, sleep habits, daily patterns (childcare vs. non-childcare hours), childcare type and sedentary time were indeterminate. Thirty-nine correlates were consistently unrelated. Forty-one potential correlates were examined in too few studies (<4) to make confident conclusions. Parental sedentary behaviour was reported 3 times and maternal sedentary behaviour was reported once. Out of these four studies, three were positively associated with child sedentary time. Conclusions: Despite reviewing 45 studies that evaluated associations for 84 correlates, this review was unable to identify any consistent correlates of sedentary time in young children. Additional research is needed in this area to provide robust evidence of the correlates of sedentary time in young children, particularly for those examined in only a small number of studies.

Seasonal variations in physical activity and sedentary behavior among preschool children in a Central China city

PURPOSE

Seasonality is an important factor in children's physical activity (PA) and sedentary behavior (SB); thus, the aim of this study was to explore the seasonal characteristics of Chinese preschool children's PA and SB.

METHOD

Preschool children (n = 65) from a kindergarten middle class in Changsha, the capital city of Hunan Province in Central China, were recruited, and a three-axis accelerometer (ActiGraph GT3X-BT) was used to longitudinally track their PA and SB status. One-way repeated-measures ANOVA (Analysis of Variance) and Friedman tests were employed for analysis, with significance set at P < .05.

RESULTS

The levels of both total of physical activity and moderate-to-vigorous physical activity were the highest in spring and the lowest in winter. The level of SB was the opposite, being the lowest in spring and the highest in winter, whereas there were no significant differences in light physical activity across different seasons. The seasonality of PA in preschool children may be influenced by several factors, such as gender, time period, preschool education curriculum, and weather conditions.

CONCLUSIONS

Seasonal variation in PA and SB are considered important for child educators, who should combine related factors to construct potentially ideal interventions to promote the PA of children during different seasons.

Objectively-measured sedentary time and physical activity in a bi-ethnic sample of young children: variation by socio-demographic, temporal and perinatal factors

Background

Evidence suggests that South Asian school-aged children and adults are less active compared to the white British population. It is unknown if this generalises to young children. We aimed to describe variability in levels of physical activity and sedentary time in a bi-ethnic sample of young children from a deprived location.

Methods

This observational study included 202 South Asian and 140 white British children aged 1.5 to 5y, who provided 3181 valid days of triaxial accelerometry (Actigraph GT3X+). Variability in sedentary time and physical activity levels were analysed by linear multilevel modelling. Logistic multilevel regression was used to identify factors associated with physical inactivity (failing to perform ≥180 min of total physical activity including ≥60 min moderate-to-vigorous physical activity (MVPA) per day).

Results

There were no significant ethnic differences in the overall levels of behaviours; South Asian and white British children spent half of daily time sedentary, just over 40% in light physical activity, and the remaining 7.5 to 8% of time in MVPA. Sedentary time was lower and physical activity levels were higher in older children, and levels of MVPA and vector magnitude counts per minute (CPM) were higher on weekends compared to weekdays. In South Asian children, sedentary time was lower on weekends. Sedentary time was lower and physical activity levels were higher in spring compared to winter in white British children, and in all seasons compared to winter in South Asian children. South Asian children born at high birth weight performed more MVPA, and in both ethnicities there was some evidence that children with older mothers were more sedentary and less active. Sedentary time was higher and light physical activity was lower in South Asian children in the highest compared to the lowest income families. South Asian girls performed less MVPA, registered fewer vector magnitude CPM, and were 3.5 times more likely to be physically inactive than South Asian boys.

Conclusions

Sedentary time and physical activity levels vary by socio-demographic, temporal and perinatal characteristics in young children from a deprived location. South Asian girls have the most to gain from efforts to increase physical activity levels.

Trial registration

The Pre-schoolers in the Playground (PiP) pilot randomized controlled trial is registered with the ISRCTN (ISRCTN54165860; http://www.isrctn.com).

Intervention Strategies to Elicit MVPA in Preschoolers during Outdoor Play

Approximately 50% of preschoolers do not meet physical activity recommendations and children who reside in low-income rural communities may be further at risk for higher levels of sedentary behavior. Outdoor play is essential for preschool children; however, literature is unclear as to which types of interventions elicit moderate-to-vigorous physical activity (MVPA) for all preschoolers. The aim of this study was to determine which type of intervention, physical activity or fundamental motor skill focus, elicits MVPA during outdoor play. Ninety-eight preschool children (M age = 4.48 years) from one Head Start center participated in an outdoor play intervention two days per week for 7 weeks. Classes were randomly assigned to one of four groups: fundamental motor skill focus (FMS), physical activity focus (PA), FMS and PA (FMS + PA), and control. An accelerometer worn on the hip measured MVPA. Results showed that age, sex and group assignment contributed to MVPA at the beginning of the intervention and age, sex, group assignment and MVPA during the beginning of the intervention contributed to MVPA at the end of the intervention. Overall, the FMS + PA group elicited MVPA from males and females of all ages. Interventions that combine both FMS and PA may reduce physical activity disparities in preschool children.

Physical activity around the clock: objectively measured activity patterns in young children of the GECKO Drenthe cohort

BACKGROUND

Given the widespread problem of physical inactivity, and the continued growth in prevalence of childhood and adolescent obesity, promotion of regular physical activity (PA) among young people has become a public priority. A greater understanding of children's PA patterns throughout the day is needed to effectively encourage children to be more physically active. Hence this study looking at the distribution of PA in young children throughout the day and its relevance to overweight.

METHODS

Accelerometers (ActiGraph GT3X, weartime > 600 min/day, ≥3 days) were used to measure the PA of 958 children (aged 5.7 ± 0.8 years, 52% boys) enrolled in the GECKO Drenthe cohort. Levels of sedentary time (ST), light PA (LPA) and moderate-to-vigorous PA (MVPA) were recorded throughout the day and analysed in segments (07:00-09:00, 09:00-12:00, 12:00-15:00, 15:00-18:00, 18:00-21:00). Body mass index was measured by Preventive Child Healthcare nurses and Cole's (2012) definition of overweight was used. General linear mixed models, adjusted for age, sex and season, were used to analyse patterns of PA and ST throughout the day.

RESULTS

Children were most sedentary in the early morning (07:00-09:00) and evening (18:00-21:00), and exhibited the most time spent engaged in LPA and MVPA in the afternoon (12:00-15:00) and late afternoon (15:00-18:00). The greatest inter-individual variation in ST, LPA and MVPA among the children occurred in the late afternoon and evening (approximately 40, 30 and 15 min difference per time segment between 25th and 75th percentile, respectively). The most active children (highest quartile of MVPA) were found to be more active and less sedentary throughout the entire day than the least active children (lowest quartile of MVPA). Furthermore, children with overweight were no less active than children without overweight.

CONCLUSIONS

At this young age, the relevance of different PA patterns to childhood overweight was minimal. Children were most active in the afternoon and late afternoon. To encourage PA in general, ST can be reduced and PA increased in the early morning and evening. Targeted PA interventions to specifically stimulate the least active children could take place in the late afternoon or evening.

Compliance with the 24-h movement guidelines and the relationship with anthropometry in Finnish preschoolers: the DAGIS study

Background

Recent 24-h movement guidelines for the early years established recommendations for physical activity (PA), screen time (ST), and sleep. To date, few studies have focused on compliance with meeting the guidelines and their associations with health outcomes. Thus, we aimed to investigate: 1) compliance with the 24-h movement guidelines, and 2) associations between compliance and anthropometry in Finnish preschoolers.

Methods

We utilized DAGIS survey data that were collected in 2015–2016 (N = 864). PA was assessed 24 h/day over 7 days using a waist-worn ActiGraph wGT3X-BT accelerometer. ST and sleep were reported by the parents during the same 7 days. Anthropometry was assessed using body mass index (BMI, kg/m²) and waist circumference (WC, cm). Children were classified as meeting the guidelines if they averaged ≥180 min/day of PA, which consisted of ≥60 min of moderate-to-vigorous intensity; ≤60 min/day of ST; and 10–13 h/day of sleep. In total, 778 children (51% boys, mean age: 4.7 ± 0.9 years) were included in the study. The compliance with meeting the 24-h movement guidelines was calculated for each behavior separately and in combinations. Adjusted linear regression analyses were applied to examine associations of compliance with BMI and WC.

Results

Children were physically active on average 390 (±46.2) min/day and spent 86 (±25.5) min/day in moderate-to-vigorous PA. They spent 76 (±37.4) min/day on ST and had on average 10:21 (±0:33) h:min/day of sleep. The compliance rate in meeting all three movement guidelines overall was 24%. The highest compliance rate was found for PA (85%), followed by sleep (76%) and ST (35%). Meeting guidelines separately for PA or sleep, or for both, were associated with lower WC (PA: B = -1.37, p < 0.001; Sleep: B = -0.72, p = 0.009; PA + Sleep: B = -1.03, p < 0.001). In addition, meeting guidelines for sleep or for both PA and sleep were associated with lower BMI (Sleep: B = -0.26, p = 0.027; PA + Sleep: B = -0.30, p = 0.007). There were no significant associations found regarding ST.

Conclusions

Meeting recommendations for PA and sleep may have an important role in supporting a healthy weight status in young children. However, there is still a need to improve compliance with the 24-h movement guidelines, especially for ST.

Later achievement of infant motor milestones is related to lower levels of physical activity during childhood: the GECKO Drenthe cohort

BACKGROUND

The aim of this study is to investigate whether age of infant motor milestone achievement is related to levels of physical activity (PA), weight status and blood pressure at age 4-7 years of age.

METHODS

In the Dutch GECKO (Groningen Expert Center of Kids with Obesity) Drenthe cohort, the age of achieving the motor milestone 'walking without support' was reported by parents. Weight status and blood pressure were assessed by trained health nurses and PA was measured using the Actigraph GT3X between age 4 and 7 years.

RESULTS

Adjusted for children's age, sex and the mother's education level, infants who achieved walking without support at a later age, spent more time in sedentary behaviour during childhood and less time in moderate-to-vigorous PA. Later motor milestones achievement was not related to higher BMI Z-score, waist circumference Z-score, diastolic or systolic blood pressure.

CONCLUSION

The results of this study indicate that a later age of achieving motor milestone within the normal range have a weak relation to lower PA levels at later age. It is not likely that this will have consequences for weight status or blood pressure at 4-7 years of age.

Predicting Early Emergence of Childhood Obesity in Underserved Preschoolers

OBJECTIVE

To determine the magnitude of risk of factors that contribute to the emergence of childhood obesity among low-income minority children.

STUDY DESIGN

We conducted a prospective cohort analysis of parent-child pairs with children aged 3-5 years who were nonobese (n = 605 pairs) who participated in a 3-year randomized controlled trial of a healthy lifestyle behavioral intervention. After baseline, height and weight were measured 5 times over 3 years to calculate body mass index (BMI) percentiles and classify children as normal, overweight, or obese. Multivariable logistic regression was used to estimate the odds of obesity after 36 months. Predictors included age, sex, birth weight, gestational age, months of breastfeeding, ethnicity, baseline child BMI, energy intake, physical activity, food security, parent baseline BMI, and parental depression.

RESULTS

Among this predominantly low-income minority population, 66% (398/605) of children were normal weight at baseline and 34% (n = 207/605) were overweight. Among normal weight children at baseline, 24% (85/359) were obese after 36 months; among overweight children at baseline, 55% (n = 103/186) were obese after 36 months. Age at enrollment (OR 2.11, 95% CI 1.64-2.72), child baseline BMI (OR 3.37, 95% CI 2.51-4.54), and parent baseline BMI (OR for a 6-unit change 1.36, 95% CI 1.09-1.70) were significantly associated with the odds of becoming obese for children.

CONCLUSIONS

The combination of child age, parent BMI, and child overweight as predictors of child obesity suggest a paradigm of family-centered obesity prevention beginning in early childhood, emphasizing the relevance of child overweight as a phenotype highly predictive of child obesity.

TRIAL REGISTRATION

Clinicaltrials.gov: NCT01316653.

Sedentary Behaviors in Today's Youth: Approaches to the Prevention and Management of Childhood Obesity: A Scientific Statement From the American Heart Association

This scientific statement is about sedentary behavior and its relationship to obesity and other cardiometabolic outcomes in youth. A deleterious effect of sedentary behavior on cardiometabolic health is most notable for screen-based behaviors and adiposity; however, this relation is less apparent for other cardiometabolic outcomes or when sedentary time is measured with objective movement counters or position monitors. Increasing trends of screen time are concerning; the portability of screen-based devices and abundant access to unlimited programming and online content may be leading to new patterns of consumption that are exposing youth to multiple pathways harmful to cardiometabolic health. This American Heart Association scientific statement provides an updated perspective on sedentary behaviors specific to modern youth and their impact on cardiometabolic health and obesity. As we reflect on implications for practice, research, and policy, what emerges is the importance of understanding the context in which sedentary behaviors occur. There is also a need to capture the nature of sedentary behavior more accurately, both quantitatively and qualitatively, especially with respect to recreational screen-based devices. Further evidence is required to better inform public health interventions and to establish detailed quantitative guidelines on specific sedentary behaviors in youth. In the meantime, we suggest that televisions and other recreational screen-based devices be removed from bedrooms and absent during meal times. Daily device-free social interactions and outdoor play should be encouraged. In addition, parents/guardians should be supported to devise and enforce appropriate screen time regulations and to model healthy screen-based behaviors.

Both increases and decreases in energy density lead to sustained changes in preschool children's energy intake over 5 days

BACKGROUND AND OBJECTIVE

To investigate preschool children's ability to self-regulate their energy intake, we assessed their response to increases or decreases in dietary energy density (ED) over 5 consecutive days, a period likely long enough for compensatory behavior.

METHODS

Using a crossover design, over 3 periods we served the same 5 daily menus to 49 children aged 3-5 y in their childcare centers. During each 5-day period, 3 main dishes and 1 snack per day were systematically varied in ED, from baseline ED to either higher ED (increased by 20%) or lower ED (decreased by 20%). All of the served items were weighed to determine individual intakes.

RESULTS

Modifying the ED of 4 dishes per day had a significant and sustained effect on preschool children's daily energy intake across 5 days. In the baseline condition, children's intakes were similar to daily energy needs (98 ± 2%), but serving higher-ED foods increased energy intake by 84 ± 16 kcal/d (to 105 ± 2% of needs) and serving lower-ED foods decreased energy intake by 72 ± 17 kcal/d (to 89 ± 2% of needs; both P < .0001). The patterns of daily energy intake over the 5 days did not differ across conditions (P = .20), thus there was no evidence that either surfeits or deficits in energy intake led to adjustment over this time period. Furthermore, the response to ED varied, as children with a higher weight status had greater amounts of overconsumption when served higher-ED foods and of underconsumption when served lower-ED foods compared to children with a lower weight status.

CONCLUSIONS

These findings counter the suggestion that preschool children's regulatory systems can be relied on to adjust intake in response to energy imbalances. Increasing or decreasing the ED of several foods per day leads to sustained changes in the energy intake of preschool children.

Environmental correlates of sedentary time and physical activity in preschool children living in a relatively rural setting in the Netherlands: a cross-sectional analysis of the GECKO Drenthe cohort

OBJECTIVES

This study examined the relationship between environmental correlates and children's sedentary time (ST), light physical activity (LPA) and moderate-to-vigorous physical activity (MVPA) in preschool children.

DESIGN

Cross-sectional study SETTING: A birth cohort in Drenthe, a northern province and relatively rural area of the Netherlands.

PARTICIPANTS

Valid data both for the ActiGraph and the questionnaire were obtained from 505 child-parent pairs.

PRIMARY AND SECONDARY OUTCOME MEASURES

ST, LPA and MVPA of children were objectively measured by ActiGraph accelerometry (minimum three wearing days, more than 10 hours/day). Environmental correlates were collected using a questionnaire reported by parents that included household characteristics, parental and children's PA behaviours and neighbourhood environment (eg, traffic safety, road network and presence of PA facilities). Potential correlates were identified using linear regression analysis, adjusted by age, gender, siblings, and maternal age and education level. Ordinary least square regression-based path analysis was used to estimate direct and indirect effects on activity outcomes in mediation models.

RESULTS

Linear regression analysis showed that 'parents taking children to play sports' was related to less ST, more LPA and MVPA; more outdoor play was also related to less ST and more LPA, but not MVPA. Parents who perceived more PA facilities in their neighbourhood showed more support for 'taking children to play sports', and this was associated with less ST or more MVPA compared with children living with less PA facilities in their neighbourhood. No evidence was found for a relation between traffic safety or road network with ST, LPA and MVPA.

CONCLUSIONS

This study indicated that parental support and child outdoor play may influence children's daily PA patterns. Convenient neighbourhood PA facilities, such as parks and playgrounds, had an indirect effect through parental support associated with lower children's ST and higher MVPA, even in relatively rural areas.

Effects of Frequency Filtering on Intensity and Noise in Accelerometer-Based Physical Activity Measurements

In objective physical activity (PA) measurements, applying wider frequency filters than the most commonly used ActiGraph (AG) filter may be beneficial when processing accelerometry data. However, the vulnerability of wider filters to noise has not been investigated previously. This study explored the effect of wider frequency filters on measurements of PA, sedentary behavior (SED), and capturing of noise. Apart from the standard AG band-pass filter (0.29-1.63 Hz), modified filters with low-pass component cutoffs at 4 Hz, 10 Hz, or removed were analyzed. Calibrations against energy expenditure were performed with lab data from children and adults to generate filter-specific intensity cut-points. Free-living accelerometer data from children and adults were processed using the different filters and intensity cut-points. There was a contribution of acceleration related to PA at frequencies up to 10 Hz. The contribution was more pronounced at moderate and vigorous PA levels, although additional acceleration also occurred at SED. The classification discrepancy between AG and the wider filters was small at SED (1-2%) but very large at the highest intensities (>90%). The present study suggests an optimal low-pass frequency filter with a cutoff at 10 Hz to include all acceleration relevant to PA with minimal effect of noise.

Accelerometer-derived physical activity estimation in preschoolers - comparison of cut-point sets incorporating the vector magnitude vs the vertical axis

Background

ActiGraph accelerometers are a widely used tool to objectively measure physical activity (PA) behavior in young children and several validated cut-point sets exist to estimate time spent in different PA intensities (sedentary time, light PA, moderate-to-vigorous PA). Applying different cut-point sets leads to large and meaningful differences in results. So far, only cut-point sets validated for the vertical axis have been compared and only the influence on time spent in moderate-to-vigorous PA has been analyzed.

Methods

A range of validated cut-point sets with their respective epoch length was applied to analyze cross-sectional data of the Swiss Preschoolers’ Health Study (SPLASHY): 1) Vertical axis in combination with an epoch length of 15 s (VA-15), 2) Vertical axis in combination with an epoch length of 60 s (VA-60) and 3) Vector magnitude in combination with an epoch length of 60 s (VM-60). PA was measured for eight consecutive days using ActiGraph accelerometers (wGT3X-BT). Three days were required to be included in the analysis (minimum two weekdays and one weekend-day with at least ten hours recording per day).

Results

Four hundred forty-five preschoolers (mean age 3.9 ± 0.5 years; 46% girls) had valid accelerometer measurements. A longer epoch (VA-60 vs VA-15) resulted in 2% less sedentary time (ST), 18% more light PA (LPA) and 51% less moderate-to-vigorous PA (MVPA); using the vector magnitude compared to the vertical axis (VM-60 vs VA-60) resulted in 34% less ST, 27% more LPA and 63% more MVPA (all p ≤ 0.001). Comparing all three sets of cut-points, ST ranged from 4.0 to 6.2 h, LPA from 5.1 to 7.6 h and MVPA from 0.8 to 1.6 h.

Conclusions

Estimated time spent in different PA intensities was strongly influenced by the choice of cut-point sets. Both, axis selection and epoch length need to be considered when comparing different studies especially when they relate PA behavior to health. The differences in the prevalence of children fulfilling PA guidelines highlight the relevance of these findings.

Trial registration

Current Controlled Trials ISRCTN41045021 (date of registration: 21.03.2014).

Electronic supplementary material

The online version of this article (10.1186/s12889-019-6837-7) contains supplementary material, which is available to authorized users.

Portion size has sustained effects over 5 days in preschool children: a randomized trial

BACKGROUND

Although short-term studies have found that serving larger portions of food increases intake in preschool children, it is unknown whether this portion size effect persists over a longer period or whether energy intake is moderated through self-regulation.

OBJECTIVES

We tested whether the portion size effect is sustained in preschool children across 5 consecutive days, a period thought to be sufficient for regulatory systems to respond to the overconsumption of energy.

METHODS

With the use of a crossover design, over 2 periods we served the same 5 daily menus to 46 children aged 3-5 y in their childcare centers. In 1 period, all foods and milk were served in baseline portions, and in the other period, all portions were increased by 50%. The served items were weighed to determine intake.

RESULTS

Increasing the portion size of all foods and milk by 50% increased daily consumption: weighed intake increased by a mean ± SEM of 143 ± 21 g/d (16%) and energy intake increased by 167 ± 22 kcal/d (18%; both P < 0.0001). The trajectories of intake by weight and energy across the 5-day period were linear and the slopes did not differ between portion conditions (both P > 0.13), indicating that there were sustained increases in intake from larger portions without compensatory changes over time. Children differed in their response to increased portions: those with higher weight status, lower ratings for satiety responsiveness, or higher ratings for food responsiveness had greater increases in intake from larger portions (all P < 0.03).

CONCLUSIONS

This demonstration that preschool children failed to adjust their intake during prolonged exposure to larger portions challenges the suggestion that their self-regulatory behavior is sufficient to counter perturbations in energy intake. Furthermore, overconsumption from large portions may play a role in the development of overweight and obesity, as the magnitude of the effect was greater in children of higher weight status. This trial was registered at www.clinicaltrials.gov as NCT02963987.

Improving nutrition and physical activity environments of family child care homes: the rationale, design and study protocol of the 'Healthy Start/Comienzos Sanos' cluster randomized trial

BACKGROUND

Early childhood is a crucial time to foster healthy eating and physical activity (PA) habits, which are critical for optimal child health, growth and development. Child care facilities are important settings to promote healthy eating and PA and prevent childhood obesity; however, almost all prior intervention studies have focused on child care centers and not family child care homes (FCCH), which care for over 1.6 million U.S. children.

METHODS

This paper describes Healthy Start/Comienzos Sanos, a cluster-randomized trial evaluating the efficacy of a multicomponent intervention to improve nutrition and PA environments in English and Spanish-speaking FCCH. Eligible child care providers complete baseline surveys and receive a two-day FCCH observation of the home environment and provider practices. Parent-consented 2-5 year-old children are measured (height, weight, waist circumference), wear accelerometers and have their dietary intake observed during child care using validated protocols. FCCH providers are then randomly assigned to receive an 8-month intervention including written materials tailored to the FCCH providers' need and interest, videos, peer support coaching using brief motivational interviewing, and periodic group meetings focused on either nutrition and PA (Intervention) or reading readiness (Comparison). Intervention materials focus on evidence-based nutrition and physical activity best practices. The initial measures (surveys, two-day observation of the FCCH and provider practices, child diet observation, physical measures, and accelerometer) are assessed again 8 and 12 months after the intervention starts. Primary outcomes are children's diet quality (Healthy Eating Index), time in moderate and vigorous PA and sedentary PA during child care. Secondary outcomes include FCCH provider practices and foods served, and PA environments and practices. Possible mediators (provider attitudes, self-efficacy, barriers and facilitators) are also being explored. Process evaluation measures to assess reach, fidelity and dose, and their relationship with dietary and PA outcomes are included.

DISCUSSION

Healthy Start/Comienzos Sanos fills an important gap in the field of childhood obesity prevention by rigorously evaluating an innovative multicomponent intervention to improve the nutrition and physical activity environments of FCCH.

TRIAL REGISTRATION

(# NCT02452645 ) ClinicalTrials.gov Trial registered on May 22, 2015.

Prediction of Physical Activity Intensity with Accelerometry in Young Children

Background: An algorithm for the classification of ambulatory and non-ambulatory activities using the ratio of unfiltered to filtered synthetic acceleration measured with a triaxial accelerometer and predictive models for physical activity intensity (METs) in adults and in elementary school children has been developed. The purpose of the present study was to derive predictive equations for METs with a similar algorithm in young children. Methods: Thirty-seven healthy Japanese children (four- to six-years old) participated in this study. The five non-ambulatory activities including low-intensity activities, and five ambulatory activities were selected. The raw accelerations using a triaxial accelerometer and energy expenditure by indirect calorimetry using the Douglas bag method during each activity were collected. Results: For non-ambulatory activities, especially light-intensity non-ambulatory activities, linear regression equations with a predetermined intercept (0.9) or quadratic equations were a better fit than the linear regression. The equations were different from those for adults and elementary school children. On the other hand, the ratios of unfiltered to filtered synthetic acceleration in non-ambulatory activities were different from those in ambulatory activities, as in adults and elementary school children. Conclusions: Our calibration model for young children could accurately predict intensity of physical activity including low-intensity non-ambulatory activities.

Effects of exergaming on motor skill competence, perceived competence, and physical activity in preschool children

BACKGROUND

Few school settings offer opportunities for preschool children to engage in structured physical activity, and only a few studies have been conducted examining exergaming's effectiveness on health outcomes in this age group. This study's purpose, therefore, was to examine a school-based exergaming intervention's effect on preschool children's perceived competence (PC), motor skill competence (MSC), and physical activity versus usual care (recess), as well as to examine gender differences for these outcomes.

METHODS

A total of 65 preschool children from 2 underserved urban schools were assigned to 1 of 2 conditions, with the school as the experimental unit: (1) usual care recess group (8 weeks of 100min of recess/week (5 days × 20 min)) and (2) exergaming intervention group (8 weeks of 100min of exergaming/week (5 days × 20 min) at school). All children underwent identical assessments of PC, MSC, and moderate-to-vigorous physical activity (MVPA) at baseline and at the end of the 8th week.

RESULTS

A significant Group × Time effect was observed for MVPA, F(1, 52) = 4.37, p = 0.04, η p 2  = 0.04, but not for PC, F(1, 52) = 0.83, p = 0.37, η p 2  = 0.02, or MSC, F(1, 52) = 0.02, p = 0.88, η p 2  = 0.00. Specifically, the intervention children displayed significantly greater increased MVPA after 8weeks than the comparison children. Additionally, there was a significant time effect for MSC, F(1, 52) = 15.61, p < 0.01, η p 2  = 0.23, and gender effect for MVPA, F(1, 52) = 5.06, p = 0.02, η p 2  = 0.09. Although all preschoolers' MSC improved across time, boys demonstrated greater MVPA than girls at both time points.

CONCLUSION

Exergaming showed a positive effect in promoting preschool children's MVPA at school and has the potential to enhance PC and MSC. More research with larger sample sizes and longer study durations are warranted.

Design and methodology of a cluster-randomized trial in early care and education centers to meet physical activity guidelines: Sustainability via Active Garden Education (SAGE)

Strategies are needed to help early care and education centers (ECEC) comply with policies to meet daily physical activity and fruit and vegetable guidelines for young children. This manuscript describes the design and methodology of Sustainability via Active Garden Education (SAGE), a 12-session cluster-randomized controlled crossover design trial using community-based participatory research (CBPR) to test a garden-based ECEC physical activity and fruit and vegetables promotion intervention for young children aged 3-5 years in 20 sites. The SAGE curriculum uses the plant lifecycle as a metaphor for human development. Children learn how to plant, water, weed, harvest, and do simple food preparation involving washing, cleaning, and sampling fruit and vegetables along with active learning songs, games, science experiments, mindful eating exercises, and interactive discussions to reinforce various healthy lifestyle topics. Parents will receive newsletters and text messages linked to the curriculum, describing local resources and events, and to remind them about activities and assessments. Children will be measured on physical activity, height, and weight and observed during meal and snack times to document dietary habits. Parents will complete measures about dietary habits outside of the ECEC, parenting practices, home physical activity resources, and home fruit and vegetable availability. SAGE fills an important void in the policy literature by employing a participatory strategy to produce a carefully crafted and engaging curriculum with the goal of meeting health policy guidelines and educational accreditation standards. If successful, SAGE may inform and inspire widespread dissemination and implementation to reduce health disparities and improve health equity.

Potential corner case cautions regarding publicly available implementations of the National Cancer Institute's nonwear/wear classification algorithm for accelerometer data

The National Cancer Institute’s (NCI) wear time classification algorithm uses a rule based on the occurrence of physical activity data counts—a cumulative measure of movement, influenced by both magnitude and duration of acceleration—to differentiate between when a physical activity monitoring (PAM) device (ActiGraph accelerometer) is being worn by a participant (wear) from when it is not (nonwear). It was applied to PAM data generated from the 2003–2004 National Health and Nutrition Examination Survey (NHANES 2003–2004). We discuss two corner case conditions that can produce unexpected, and perhaps unintended results when the algorithm is applied. We show, using simulated data of two special cases, how this algorithm classifies a 24-hour period with only 72 total counts as 100% wear in one case, and classifies a 24-hour period with 96,000 counts as 0.1% wear in another. The prevalence of like scenarios in the NHANES 2003–2004 PAM dataset is presented with corresponding summary statistics for varying degrees of the algorithm’s nonwear classification threshold (T). The number of participants with valid days, defined as 10 or more hours classified as wear time in a 24-hour day, increased while the mean counts-per-minute (CPM) decreased as the threshold for excluding non-wear was reduced from the allowed 4,000 counts in an hour. The number of participants with four or more valid days increased 2.29% (n = 113) and mean CPM dropped 2.45% (9.5 CPM) when adjusting the nonwear classification threshold to 50 counts an hour. Applying the most liberal criteria, only excluding hours as nonwear which contained 1 count or less, resulted in a 397 more participants (7.83% increase) and 26.5 fewer CPM (6.98% decrease) in NHANES 2003–2004 participants with four or more valid days. The algorithm should be used with caution due to the potential influence of these corner cases.

Sensor-enabled Activity Class Recognition in Preschoolers: Hip versus Wrist Data

PURPOSE

Pattern recognition approaches to accelerometer data processing have emerged as viable alternatives to cut-point methods. However, few studies have explored the validity of pattern recognition approaches in preschoolers, and none have compared supervised learning algorithms trained on hip and wrist data. Purpose of this study was to develop, test, and compare activity class recognition algorithms trained on hip, wrist, and combined hip and wrist accelerometer data in preschoolers.

METHODS

Eleven children 3-6 yr of age (mean age, 4.8 ± 0.9 yr) completed 12 developmentally appropriate physical activity (PA) trials while wearing an ActiGraph GT3X+ accelerometer on the right hip and nondominant wrist. PA trials were categorized as sedentary, light activity games, moderate-to-vigorous games, walking, and running. Random forest (RF) and support vector machine (SVM) classifiers were trained using time and frequency domain features from the vector magnitude of the raw signal. Features were extracted from 15-s nonoverlapping windows. Classifier performance was evaluated using leave-one-out cross-validation.

RESULTS

Cross-validation accuracy for the hip, wrist, and combined hip and wrist RF models was 0.80 (95% confidence interval (CI), 0.79-0.82), 0.78 (95% CI, 0.77-0.80), and 0.82 (95% CI, 0.80-0.83), respectively. Accuracy for hip, wrist, and combined hip and wrist SVM models was 0.81 (95% CI, 0.80-0.83), 0.80 (95% CI, 0.79-0.80), and 0.85 (95% CI, 0.84-0.86), respectively. Recognition accuracy was consistently excellent for sedentary (>90%); moderate for light activity games, moderate-to-vigorous games, and running (69%-79%); and modest for walking (61%-71%).

CONCLUSIONS

Machine learning algorithms such as RF and SVM are useful for predicting PA class from accelerometer data collected in preschool children. Although classifiers trained on hip or wrist data provided acceptable recognition accuracy, the combination of hip and wrist accelerometer delivered better performance.

Prevalence of objectively measured sedentary behavior in early years: Systematic review and meta-analysis

BACKGROUND

The early years have been identified as a critical period during which sedentary habits may be established, as this behavior appears to track throughout life.

OBJECTIVE

The purpose of this systematic review and meta-analysis is to summarize the current literature on the prevalence of sedentary behavior in children aged 1-5.99 years, reporting differences between boys and girls, weekdays and weekend days, childcare hours and nonchildcare hours, and between time spent indoors and outdoors while children attended childcare.

METHODS

Five databases were searched until 26.10.2017 and meta-analyses were conducted to estimate prevalence and calculate mean differences in prevalence between groups.

RESULTS

Fifty studies representing 14 598 children (2-5.99 years) were included. Children spent 51.4% of their waking time in sedentary behaviors. Boys spent less time being sedentary than girls (estimate difference = -1.4%; 95%CI = -2.0: -0.7; P < .001). No significant differences were found between weekdays/weekend days (estimate difference = -0.4; 95%CI = -2.0: 1.2; P = .61) nor between childcare hours/nonchildcare hours (estimate difference = %; 95%CI = -0.9: 6.6; P = .136). While attending childcare centers, children were more sedentary indoors than outdoors (estimate difference = 14.4%; 95%CI = 11.8: 16.9; P < .001).

CONCLUSIONS

Our results suggest that young children spend a significant portion of their waking hours in sedentary behaviors. While at childcare, young children accumulated more sedentary behavior indoors than outdoors. Girls were more likely to be more sedentary than boys. No significant differences were found between weekdays and weekends, or between childcare and nonchildcare hours. There is a need for higher-quality studies with strong designs, using age and device appropriate cut-off points, to improve evidence-base and to better establish prevalence of sedentary behavior in young children.

"Oh oobe doo, I wanna be like you" associations between physical activity of preschool staff and preschool children

OBJECTIVE

Physical activity contributes to prevent serious diseases and ailments, and previous research indicates that lifestyle habits are likely to track from early childhood to adulthood. 90% of Norwegian children aged 1-5 are enrolled in preschools, and preschool staff can play an important role in children's activity levels. This study's aim was to identify whether any associations exist between preschool staff's characteristics (initiative, participation, attitudes, and activity levels) and children's activity in preschool.

METHOD

289 children aged 4-6 and 72 preschool staff from 13 randomly selected preschools in a region of Nord-Troendelag, Norway, were enrolled in the study. All participants wore an Actigraph accelerometer for seven consecutive days. Questionnaires were also utilized to identify correlates between preschool staff's attitudes and initiative in relation to children's physical activity, in addition to their participation in children's physical activity. A multilevel analysis, the linear mixed model (LMM), was used to elucidate associations between preschool staff and children's activity levels.

RESULTS

A significant association was found between preschool staff's average activity levels during preschool hours and children's corresponding activity levels during preschool hours (t = 2.57; p = 0.021; f2 = 0.013). There were, however, no significant associations identified between the attitudes (t = -0.44; p = 0.67), initiative (t = -0.14; p = 0.89), and participation (t = 0.66; p = 0.52) variables among preschool staff and children's activity levels during preschool hours.

CONCLUSION

The study demonstrated that a significant association exists between preschool staff's aggregated activity levels and 4-6-year-olds' individual activity levels. However, an observational study is requisite in order to determine whether the association is based on preschool staff's impact on children's physical activity or if it is the children that affect the preschool staff's activity levels, or a combination thereof.

Accelerometer Data Collection and Processing Criteria to Assess Physical Activity and Other Outcomes: A Systematic Review and Practical Considerations

BACKGROUND

Accelerometers are widely used to measure sedentary time, physical activity, physical activity energy expenditure (PAEE), and sleep-related behaviors, with the ActiGraph being the most frequently used brand by researchers. However, data collection and processing criteria have evolved in a myriad of ways out of the need to answer unique research questions; as a result there is no consensus.

OBJECTIVES

The purpose of this review was to: (1) compile and classify existing studies assessing sedentary time, physical activity, energy expenditure, or sleep using the ActiGraph GT3X/+ through data collection and processing criteria to improve data comparability and (2) review data collection and processing criteria when using GT3X/+ and provide age-specific practical considerations based on the validation/calibration studies identified.

METHODS

Two independent researchers conducted the search in PubMed and Web of Science. We included all original studies in which the GT3X/+ was used in laboratory, controlled, or free-living conditions published from 1 January 2010 to the 31 December 2015.

RESULTS

The present systematic review provides key information about the following data collection and processing criteria: placement, sampling frequency, filter, epoch length, non-wear-time, what constitutes a valid day and a valid week, cut-points for sedentary time and physical activity intensity classification, and algorithms to estimate PAEE and sleep-related behaviors. The information is organized by age group, since criteria are usually age-specific.

CONCLUSION

This review will help researchers and practitioners to make better decisions before (i.e., device placement and sampling frequency) and after (i.e., data processing criteria) data collection using the GT3X/+ accelerometer, in order to obtain more valid and comparable data.

PROSPERO REGISTRATION NUMBER

CRD42016039991.

Childcare Correlates of Physical Activity, Sedentary Behavior, and Adiposity in Preschool Children: A Cross-Sectional Analysis of the SPLASHY Study

Background

The childcare (CC) environment can influence young children's physical activity (PA), sedentary behavior (SB), and adiposity. The aim of the study was to identify a broad range of CC correlates of PA, SB, and adiposity in a large sample of preschoolers.

Methods

476 preschool children (mean age 3.9 yrs; 47% girls) participated in the Swiss Preschoolers' Health Study (SPLASHY). PA and SB were measured by accelerometry. Outcome measures included total PA (TPA), moderate-to-vigorous PA (MVPA), SB, body mass index (BMI), and skinfold thickness (SF). PA measures consisted of both daily PA during CC attendance days and overall daily PA (CC and non-CC days).

Results

We identified the following CC correlates for higher TPA and/or higher MVPA or lower SB during CC attendance days: older age, sex (boys), more frequent child-initiated interactions during CC, mixing different ages within a group, and the presence of a written PA policy in the CC (all p ≤ 0.02). The CC correlates for overall TPA and/or MVPA or lower overall SB including both CC and non-CC days were the following: older age, sex (boys), more frequent child-initiated interactions during CC, mixing different ages within a group, less parental PA involvement in the CC, and having a larger surface area in CC (all p ≤ 0.046). Correlates for lower SF were sex (boys) and parental PA involvement in the CC (all p ≤ 0.02), and, for lower BMI, only increased age (p=0.001) was a correlate.

Conclusions

More frequent child-initiated interactions and mixing different ages in CC, the presence of a written PA policy, and a larger CC surface are correlates of PA and SB during CC attendance days and/or of overall PA. Parental involvement in CC PA projects was a correlate for reduced body fat. These novel factors are mostly modifiable and can be tackled/addressed in future interventions.

Device-measured physical activity data for classification of patients with ventricular arrhythmia events: A pilot investigation

Low levels of physical activity are associated with increased mortality risk, especially in cardiac patients, but most studies are based on self-report. Cardiac implantable electronic devices (CIEDs) offer an opportunity to collect data for longer periods of time. However, there is limited agreement on the best approaches for quantification of activity measures due to the time series nature of the data. We examined physical activity time series data from 235 subjects with CIEDs and at least 365 days of uninterrupted measures. Summary statistics for raw daily physical activity (minutes/day), including statistical moments (e.g., mean, standard deviation, skewness, kurtosis), time series regression coefficients, frequency domain components, and forecasted predicted values, were calculated for each individual, and used to predict occurrence of ventricular tachycardia (VT) events as recorded by the device. In unsupervised analyses using principal component analysis, we found that while certain features tended to cluster near each other, most provided a reasonable spread across activity space without a large degree of redundancy. In supervised analyses, we found several features that were associated with the outcome (P < 0.05) in univariable and multivariable approaches, but few were consistent across models. Using a machine-learning approach in which the data was split into training and testing sets, and models ranging in complexity from simple univariable logistic regression to ensemble decision trees were fit, there was no improvement in classification of risk over naïve methods for any approach. Although standard approaches identified summary features of physical activity data that were correlated with risk of VT, machine-learning approaches found that none of these features provided an improvement in classification. Future studies are needed to explore and validate methods for feature extraction and machine learning in classification of VT risk based on device-measured activity.

Accelerometer Data Processing and Energy Expenditure Estimation in Preschoolers

PURPOSE

To assess the capacity of different acceleration metrics from wrist accelerations to estimate total energy expenditure (TEE) and activity energy expenditure (AEE) using doubly labeled water in preschool children.

METHODS

Thirty-nine preschoolers (5.5 ± 0.1 yr) were included. Total energy expenditure was measured using doubly labeled water during 14 d, and AEE was then calculated using a predicted basal metabolic rate. Participants wore a wGT3X-BT accelerometer on their nondominant wrist for ≥5 d. We derived the following metrics from raw accelerations: raw ActiGraph activity counts using the normal filter and the low-frequency extension; and alternate summary metrics, such as the Euclidian norm minus 1g (ENMO), Euclidian norm of the high-pass-filtered accelerations (HFEN), the bandpass-filtered accelerations, the HFEN plus Euclidean norm of low-pass filtered accelerations minus 1g (HFEN+) and the mean amplitude deviation.

RESULTS

Alternate summary metrics explained a larger proportion of the variance in TEE and AEE than ActiGraph's activity counts (counts, 7-8 and 25% of TEE and AEE; alternate summary metrics, 13%-16% and 35%-39% of TEE and AEE). Adjustments for body weight and height resulted in an explanation of 51% of AEE by ENMO. All of the metrics adjusted for fat mass and fat-free mass explained up to 84% and 67% of TEE and AEE, respectively.

CONCLUSIONS

ENMO and the other alternate summary metrics explained more of the variance in TEE and AEE than the ActiGraph's activity counts in 5-yr-old children, suggesting further exploration of these variables in studies on physical activity and energy expenditure in preschoolers. Our results need confirmation in other populations with wider age groups and varying body compositions.

An open-source tool to identify active travel from hip-worn accelerometer, GPS and GIS data

Background

Increases in physical activity through active travel have the potential to have large beneficial effects on populations, through both better health outcomes and reduced motorized traffic. However accurately identifying travel mode in large datasets is problematic. Here we provide an open source tool to quantify time spent stationary and in four travel modes(walking, cycling, train, motorised vehicle) from accelerometer measured physical activity data, combined with GPS and GIS data.

Methods

The Examining Neighbourhood Activities in Built Living Environments in London study evaluates the effect of the built environment on health behaviours, including physical activity. Participants wore accelerometers and GPS receivers on the hip for 7 days. We time-matched accelerometer and GPS, and then extracted data from the commutes of 326 adult participants, using stated commute times and modes, which were manually checked to confirm stated travel mode. This yielded examples of five travel modes: walking, cycling, motorised vehicle, train and stationary. We used this example data to train a gradient boosted tree, a form of supervised machine learning algorithm, on each data point (131,537 points), rather than on journeys. Accuracy during training was assessed using five-fold cross-validation. We also manually identified the travel behaviour of both 21 participants from ENABLE London (402,749 points), and 10 participants from a separate study (STAMP-2, 210,936 points), who were not included in the training data. We compared our predictions against this manual identification to further test accuracy and test generalisability.

Results

Applying the algorithm, we correctly identified travel mode 97.3% of the time in cross-validation (mean sensitivity 96.3%, mean active travel sensitivity 94.6%). We showed 96.0% agreement between manual identification and prediction of 21 individuals’ travel modes (mean sensitivity 92.3%, mean active travel sensitivity 84.9%) and 96.5% agreement between the STAMP-2 study and predictions (mean sensitivity 85.5%, mean active travel sensitivity 78.9%).

Conclusion

We present a generalizable tool that identifies time spent stationary and time spent walking with very high precision, time spent in trains or vehicles with good precision, and time spent cycling with moderate precisionIn studies where both accelerometer and GPS data are available this tool complements analyses of physical activity, showing whether differences in PA may be explained by differences in travel mode. All code necessary to replicate, fit and predict to other datasets is provided to facilitate use by other researchers.

Electronic supplementary material

The online version of this article (10.1186/s12966-018-0724-y) contains supplementary material, which is available to authorized users.

Parental physical activity is associated with objectively measured physical activity in young children in a sex-specific manner: the GECKO Drenthe cohort

BACKGROUND

Physical activity (PA) is important in combating childhood obesity. Parents, and thus parental PA, could influence PA in young children. We examined whether the time spent at different intensities of PA and the type of parental PA are associated with the PA of children aged 4-7 years, and whether the associations between child-parent pairs were sex-specific.

METHODS

All the participants were recruited from the Groningen Expert Center for Kids with Obesity (GECKO) birth cohort (babies born between 1 April 2006 and 1 April 2007 in Drenthe province, the Netherlands) and were aged 4-7 years during measurement. PA in children was measured using the ActiGraph GT3X (worn at least 3 days, ≥10 h per day). PA in parents was assessed using the validated SQUASH questionnaire.

RESULTS

Of the N = 1146 children with valid ActiGraph data and 838 mothers and 814 fathers with valid questionnaire data, 623 child-parent pairs with complete data were analysed. More leisure time PA in mothers was associated with more time spent in moderate-to-vigorous PA (MVPA) in children (Spearman r = 0.079, P < .05). Maternal PA was significantly related to PA in girls, but not boys. More time spent in maternal vigorous PA, in sports activity, and leisure time PA, were all related to higher MVPA in girls (Spearman r = 0.159, r = 0.133 and r = 0.127 respectively, Pall < .05). In fathers, PA levels were predominantly related to PA in sons. High MVPA in fathers was also related to high MVPA in sons (r = 0.132, P < 0.5). Spending more time in light PA was related to more sedentary time and less time in MVPA in sons.

CONCLUSIONS

Higher PA in mothers, for instance in leisure activities, is related to higher PA in daughters, and more active fathers are related to more active sons. To support PA in young children, interventions could focus on the PA of the parent of the same sex as the child. Special attention may be needed for families where the parents have sedentary jobs, as children from these families seem to adopt more sedentary behaviour.

Effect of a Behavioral Intervention for Underserved Preschool-Age Children on Change in Body Mass Index: A Randomized Clinical Trial

Importance

Prevention of obesity during childhood is critical for children in underserved populations, for whom obesity prevalence and risk of chronic disease are highest.

Objective

To test the effect of a multicomponent behavioral intervention on child body mass index (BMI, calculated as weight in kilograms divided by height in meters squared) growth trajectories over 36 months among preschool-age children at risk for obesity.

Design, Setting, and Participants

A randomized clinical trial assigned 610 parent-child pairs from underserved communities in Nashville, Tennessee, to a 36-month intervention targeting health behaviors or a school-readiness control. Eligible children were between ages 3 and 5 years and at risk for obesity but not yet obese. Enrollment occurred from August 2012 to May 2014; 36-month follow-up occurred from October 2015 to June 2017.

Interventions

The intervention (n = 304 pairs) was a 36-month family-based, community-centered program, consisting of 12 weekly skills-building sessions, followed by monthly coaching telephone calls for 9 months, and a 24-month sustainability phase providing cues to action. The control (n = 306 pairs) consisted of 6 school-readiness sessions delivered over the 36-month study, conducted by the Nashville Public Library.

Main Outcomes and Measures

The primary outcome was child BMI trajectory over 36 months. Seven prespecified secondary outcomes included parent-reported child dietary intake and community center use. The Benjamini-Hochberg procedure corrected for multiple comparisons.

Results

Participants were predominantly Latino (91.4%). At baseline, the mean (SD) child age was 4.3 (0.9) years; 51.9% were female. Household income was below $25 000 for 56.7% of families. Retention was 90.2%. At 36 months, the mean (SD) child BMI was 17.8 (2.2) in the intervention group and 17.8 (2.1) in the control group. No significant difference existed in the primary outcome of BMI trajectory over 36 months (P = .39). The intervention group children had a lower mean caloric intake (1227 kcal/d) compared with control group children (1323 kcal/d) (adjusted difference, -99.4 kcal [95% CI, -160.7 to -38.0]; corrected P = .003). Intervention group parents used community centers with their children more than control group parents (56.8% in intervention; 44.4% in control) (risk ratio, 1.29 [95% CI, 1.08 to 1.53]; corrected P = .006).

Conclusions and Relevance

A 36-month multicomponent behavioral intervention did not change BMI trajectory among underserved preschool-age children in Nashville, Tennessee, compared with a control program. Whether there would be effectiveness for other types of behavioral interventions or implementation in other cities would require further research.

Trial Registration

ClinicalTrials.gov Identifier: NCT01316653.

In preschool children, physical activity during school time can significantly increase by intensifying locomotor activities during physical education classes

OBJECTIVES

After categorizing preschool children into "active and low active" according to their moderate and vigorous physical activity (MVPA) in PE classes (PE), we compared these two groups within each sex and by sex in: (a) % MVPA and MVPA minutes accrued from each fundamental motor skill (FMS) during PE and (b) % MVPA during school time.

RESULTS

532 children (mean age 5.2 years, 50% girls) were selected from a nationwide program which provides 3 weekly PE. Children wore accelerometers during one school day which included PE. We recorded the type and duration of each activity indicated by the teacher, classifying each one into the corresponding FMS, extracting its MVPA minutes from the accelerometer software. Children were categorized into active and low active. Comparisons used T-tests. In PE, active children accumulate 40 and 36 percentage points (pp) more MVPA minutes (boys and girls respectively), while during school time, 4 pp more in each sex. Girls are significantly less active. Just considering locomotion, active boys and girls accumulate 11 more MVPA minutes during PE. Active boys surpass the MVPA guideline for PE, while active girls almost reach it. Low active children (especially girls) should intensify locomotor activities during PE.

Cross-sectional and prospective associations of meeting 24-h movement guidelines with overweight and obesity in preschool children

BACKGROUND

Cross-sectional studies report that meeting the newly developed 24-h movement guidelines (≥60 min moderate to vigorous physical activity (MVPA), ≤120 min screen time and 9-11 h sleep duration) are associated with lower adiposity indicators in children. However, prospective data are absent.

METHODS

The study sample consisted of 830 children from the PRIMROSE study with GT3X+ accelerometer measured physical activity and parent reported screen time and sleep duration at age 4 years and objectively measured anthropometrics at age 4 and 5 years. The main outcome variables were weight status, body mass index (BMI) and BMI z-score at ages 4 and 5 years. Exposure variables were defined as meeting vs. not meeting the 24-h movement guidelines and combinations of these recommendations.

RESULTS

On average, 18.4% of the total study sample met the combination of MVPA, sleep duration and screen time recommendations. In isolation, the MVPA, screen time and sleep guidelines were met by 31%, 63% and 98% of the total study sample, respectively. Adherence to any single recommendation, or any combination of recommendations at age 4 years, was not associated with being overweight or obese nor with BMI and BMI z-score at age 4 or 5 years.

CONCLUSIONS

In contrast to previous cross-sectional studies, neither individual movement behaviours nor combinations of behaviours at age 4 years was associated with overweight or obesity, BMI or BMI z-score at age 4 or 5 years. More prospective data are needed before effects on weight status from meeting the 24-h movement guidelines are elucidated.

Guelph Family Health Study: pilot study of a home-based obesity prevention intervention

OBJECTIVE

To examine the feasibility and preliminary impact of a home-based obesity prevention intervention among Canadian families.

METHODS

Families with children 1.5-5 years of age were randomized to one of three groups: (1) four home visits (HV) with a health educator, emails, and mailed incentives (4HV; n = 17); (2) two HV, emails, and mailed incentives (2HV; n = 14); or (3) general health advice through emails (control; n = 13). Parents randomized to the 2HV and 4HV groups completed post-intervention satisfaction surveys. At baseline and post-intervention, parents reported frequency of family meals and their children's fruit, vegetable, and sugar-sweetened beverage (SSB) intake. We assessed the children's physical activity, sedentary behaviour, and sleep using accelerometers and their % fat mass using bioelectrical impedance analysis. Differences in outcomes at post-intervention, controlling for baseline, were examined using generalized estimating equations.

RESULTS

Of the 44 families enrolled, 42 (96%) had 6-month outcome data. Satisfaction with the intervention was high; 80% were "very satisfied" and 20% were "satisfied." At post-intervention, children randomized to the 4HV and 2HV groups had significantly higher fruit intake and children randomized to the 2HV group had significantly lower percentage of fat mass, as compared to the control. No significant intervention effect was found for frequency of family meals, the children's vegetable or SSB intake, physical activity, sedentary behaviour, or sleep.

CONCLUSIONS

Our results suggest that the delivery of a home-based intervention is feasible among Canadian families and may lead to improved diet and weight outcomes among children. A full-scale trial is needed to test the effectiveness of this home-based intervention.

CLINICAL TRIALS REGISTRATION NUMBER

NCT02223234.

Joint Relationship Between Physical Activity, Weight Status, and Motor Skills in Children Aged 3 to 10 Years

While the relationships between physical activity (PA), obesity, and motor skills have been independently examined by previous research, this study explored both independent and combined relationships between children's PA, weight status, and motor skills within a multiple regression analysis. We measured height and weight and calculated body mass index (BMI) z scores for 96 children (3-10 years of age). We measured motor skills using the Movement Assessment Battery for Children-2nd edition (MABC-2), and we measured PA levels through accelerometry. Children with more time in moderate and moderate-to-vigorous PA had higher Total motor skill scores on the MABC-2. Further, children with higher moderate PA levels had higher Balance scores and those with moderate-to-vigorous PA demonstrated higher Aiming and Catching scores. Among children with healthier BMIs, more time spent in PA, regardless of intensity, was related to higher Aiming and Catching scores. Among children with BMI scores suggestive of overweight/obesity, both moderate and moderate-to-vigorous PA were positively related to Balance scores. In conclusion, while BMI z scores were not directly related to motor skills, PA levels were positively related to motor skills, and weight status mediated the relationship between PA and specific components of motor skills.

Cross-sectional associations between maternal self-efficacy and dietary intake and physical activity in four-year-old children of first-time Swedish mothers

BACKGROUND

Healthy dietary and physical activity behaviours are established early in life where children learn by observing their parents. Therefore, parents can act as role models and influence their children toward a healthier lifestyle. Besides a strong association between parental and child health behaviours, parents also influence their children's health behaviours through socio-cognitive processes, where perceived self-efficacy is the central component. The objective was to examine if parental self-efficacy among Swedish mothers was associated with their four-year-old children's dietary and physical activity behaviours.

METHODS

This cross-sectional study was based on information from control participants that took part in the Swedish primary prevention trial of childhood obesity (PRIMROSE) (n = 420 mother-child pairs). Linear regression models were used to examine the associations between parental self-efficacy (Parental Self-Efficacy for Promoting Healthy Physical Activity and Dietary Behaviours in Children Scale) and children's dietary intake (parent reported) and levels of physical activity (accelerometer) with adjustments for potential confounders.

RESULTS

Mothers' efficacy beliefs in promoting healthy dietary or physical activity behaviours in their children were associated with a slightly higher consumption of fruit and vegetables among their children (β: 0.03 [95%CI: 0.01; 0.04] P < 0.001) and slightly higher levels of moderate-to-vigorous activity (β: 0.43 [95%CI: 0.05; 0.81] P = 0.03). Mothers' belief in their ability to limit unhealthy dietary and physical activity behaviours was inversely associated with children's intake of unhealthy snacks (β: -0.06 [95%CI: -0.10; -0.02] P < 0.01).

CONCLUSION

Our cross-sectional study suggests weak positive correlations between maternal self-efficacy and healthy dietary and physical activity behaviours, and weak inverse associations between maternal self-efficacy and unhealthy dietary and physical activity behaviours among their children.

Accelerometer-Measured Patterns of Shared Physical Activity Among Mother-Young Child Dyads

BACKGROUND

Many mothers and young children are not meeting physical activity guidelines. Parent-child coparticipation in physical activity (ie, shared physical activity) provides opportunities for social modeling and might be associated with child physical activity. There is very little information about shared physical activity using objective measures.

METHODS

Participants (N = 17 mother-young child dyads) completed a demographic survey and height/weight measurements, and wore a Bluetooth^® accelerometer for 1 week. Accelerometers were initialized using the proximity function to yield both individual and proximity [a minute-by-minute log of whether the 2 accelerometers were in- or out-of-range (∼50 m or less)] data. Shared physical activity was calculated in MATLAB by overlaying individual and proximity accelerometer data.

RESULTS

Mother-child dyads spent approximately 2 hours per day in shared time that was mostly shared sedentary activities. Less than 1% of shared minutes per day were spent in shared moderate to vigorous physical activity.

CONCLUSIONS

Mothers and young children spent a small portion of their day in shared activities. Most mother-child shared time was spent in sedentary or light activities rather than moderate to vigorous physical activity. This method for objectively measuring shared physical activity provides novel information about the context in which physical activity occurs and could be used to understand patterns of physical activity among other dyads.

A Sport Education Fitness Season's Impact on Students' Fitness Levels, Knowledge, and In-Class Physical Activity

PURPOSE

The purpose of this study was to determine the extent to which a sport education season of fitness could provide students with recommended levels of in-class moderate-to-vigorous physical activity (MVPA) while also increasing students' fitness knowledge and fitness achievement.

METHOD

One hundred and sixty-six 5th-grade students (76 boys, 90 girls) participated in a 20-lesson season called "CrossFit Challenge" during a 4-week period. The Progressive Aerobic Cardiovascular Endurance Run, push-ups, and curl-ups tests of the FITNESSGRAM® were used to assess fitness at pretest and posttest, while fitness knowledge was assessed through a validated, grade-appropriate test of health-related fitness knowledge (HRF). Physical activity was measured with Actigraph GT3X triaxial accelerometers.

RESULTS

Results indicated a significant time effect for all fitness tests and the knowledge test. Across the entire season, the students spent an average of 54.5% of lesson time engaged in MVPA, irrespective of the type of lesson (instruction, free practice, or competition).

CONCLUSIONS

The results suggest that configuring the key principles of sport education within a unit of fitness is an efficient model for providing students with the opportunity to improve fitness skill and HRF knowledge while attaining recommended levels of MVPA.

Preschoolers' Physical Activity Participation Across a Yearlong Mastery-Motivational Climate Intervention

PURPOSE

This study sought to determine how children's participation in physical activity during a mastery-motivational climate changed during a 20-week intervention and to compare it to children's free-play activity during a typical day at their local day-care facility.

METHOD

Twelve 4-year-old children participated in a mastery-motivational climate physical activity program delivered 2 days a week for 20 weeks during a period of 8 months. All children were fitted with an Actigraph GT3X triaxial accelerometer. Data from the accelerometers were reduced to determine minutes of sedentary time, light physical activity, and moderate-to-vigorous physical activity (MVPA) during (a) all 20 weeks, and (b) Weeks 1 through 4, Weeks 9 through 12, and Weeks 17 to 20 for the mastery climate. Activity levels in the mastery condition were compared to the children's activity during unplanned free play in Weeks 1, 10, and 20.

RESULTS

During the course of the mastery-motivational climate program, participation in sedentary behavior decreased statistically significantly, while participation in MVPA increased statistically significantly. Within the free-play condition, there were no changes in the levels of activity across time, with the children spending on average more than 80% of their time being sedentary.

CONCLUSIONS

Findings indicate that when specific task structures associated with a mastery climate are included in an instructional setting, these climate manipulations seem to have a direct effect on physical activity levels once the children learned how to manage themselves in the setting. Free-play activity in and of itself does not appear to stimulate MVPA.

Preschool children's physical activity intensity during school time: Influence of school schedule

Chile's Physical Activity Report Card graded the overall index on PA behavior with an F The Ministry of Sports is implementing since 2014 “Jardín Activo” (JA program) which recommends 3 weekly teacher-led PE lessons for preschool children, on half or full day attendance. We determined the effectiveness of the JA program (contribution to MVPA during school time) and assessed if effectiveness varied according to schedule. 596 five y olds, (50% boys) were selected from 66 schools; 52.9% attended half day and 47.1% full day. Children wore accelerometers during school time a day with and one without PE lesson (JA day/non JA day). We compared PA intensity between both these days by gender, using descriptive statistics and t-tests and determined the differential effect on PA intensity, between non JA and JA days by school schedule, using mixed models analyses We compared β of sedentary and of MVPA by schedule with t-tests. Significant differences were found in PA intensity between both days within each gender. Minutes being sedentary were significantly less during JA days (14 and 15 min in boys and girls respectively); MVPA significantly higher in JA days (11 and 10 min respectively). % time children were sedentary and % they engaged in MVPA differed by schedule. Sedentary minutes were significantly higher (β − 16.2 vs − 13.2) in half day, while the increase in MVPA was significantly higher (β 12.5 vs 9.7) in full day. The JA program is effective, especially when children attend school full time.

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PE lessons taught by specialists to preschool children are very effective.

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This effect varies by school schedule.

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The decline in sedentary minutes is greater in children attending half day.

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The increase in MVPA is higher in children attending full day.