Development and Testing of the Observational System for Recording Physical Activity in Children-Toddlers

Background: Direct observation (DO) tools developed for preschoolers have been used to describe toddler physical activity (PA). No DO system created to assess PA levels and the childcare environment of toddlers exists. The purpose of this study was to develop the Observational System for Recording Physical Activity in Children-Toddlers (OSRAC-T) and assess the inter- and intra-rater reliability. Methods: This tool is an extension of the Observational System for Recording Physical Activity in Children-Preschool and uses the same focal child, time sampling system (5-second observation and 25-second recording). Tool content was established through identifying similar research, consulting with experts, and conducting informal observations. A sample of toddlers (12-36 months) was observed and video recorded during childcare. In-person observations were compared to video observations from one coder (intrarater reliability). Video observations (39% of intervals) were coded by two raters to determine interrater reliability. Results: The final instrument included nine categories that described PA level and type, social and environmental contexts, and transition support relevant to toddlers. Observers completed 124 observation sessions (n = 31; 25.5 ± 6.0 months) resulting in 7,757 30-second observation intervals. Interval-by-interval agreement was moderate to high (58.90%-95.30%) for all categories, and interrater reliability was low to moderate (k = 0.28-0.69). Conclusion: The OSRAC-T is a reliable observation system to assess several PA-related behaviors of toddlers. It may be used to better inform early childcare center design, future intervention studies, or to assess correlates or relationships between PA behavior and health outcomes in toddlers.

Accelerometer Monitoring Duration for Reliable Estimates of Physical Activity, Sedentary Behavior, and Step Counts in Preschoolers

PURPOSE

This study aims to establish the reliability of accelerometer-based measurements for physical activity, sedentary behavior, and step counts in preschoolers and determine the optimal monitoring duration necessary for reliable data.

METHODS

The study analyzed data from 434 preschoolers (ages 3-5) who wore waist-worn ActiGraph wGT3X-BT accelerometers for 7 days as part of the Sunrise Study in Spain. Two-way mixed effects intraclass correlation coefficients were calculated for various combinations of daily wear time and number of valid days to assess reliability. The Spearman-Brown prophecy formula was applied to determine the required days to achieve reliability scores of 0.7, 0.8, and 0.9.

RESULTS

The findings showed that reliability improved with increased wear time, although intraclass correlation coefficients values were weaker around 7 to 9 hours per day. To achieve a reliability score of 0.7, moderate to vigorous physical activity required 3 to 4 days, light physical activity required 4 to 7 days, and sedentary behavior required 8 to 13 days. Steps per day required 7 to 9 days for a reliability score of 0.7, while other step outcomes needed 10 to 13 days.

CONCLUSION

The study provides evidence-based recommendations on the monitoring duration required for reliable estimates of physical activity, sedentary behavior, step counts, and sleep duration in preschoolers using accelerometers. These findings are crucial for researchers and practitioners aiming to accurately assess and promote physical activity in early childhood.

Effect of wearable activity trackers on physical activity in children and adolescents: a systematic review and meta-analysis

BACKGROUND

Physical inactivity in children and adolescents has become a pressing public health concern. Wearable activity trackers can allow self-monitoring of physical activity behaviour and promote autonomous motivation for exercise. However, the effects of wearable trackers on physical activity in young populations remain uncertain.

METHODS

In this systematic review and meta-analysis, we searched PubMed, Embase, SPORTDiscus, and Web of Science for publications from database inception up to Aug 30, 2023, without restrictions on language. Studies were eligible if they were randomised controlled trials or clustered randomised controlled trials that examined the use of wearable activity trackers to promote physical activity, reduce sedentary behaviours, or promote overall health in participants with a mean age of 19 years or younger, with no restrictions on health condition or study settings. Studies were excluded if children or adolescents were not the primary intervention cohort, or wearable activity trackers were not worn on users' bodies to objectively track users' physical activity levels. Two independent reviewers (WWA and FR) assessed eligibility of studies and contacted authors of studies if more information was needed to assess eligibility. We also searched reference lists from relevant systematic reviews and meta-analyses. Systematic review software Covidence was used for study screening and data extraction. Study characteristics including study setting, participant characteristics, intervention characteristics, comparator, and outcome measurements were extracted from eligible studies. The two primary outcomes were objectively measured daily steps and moderate-to-vigorous physical activity. We used a random-effects model with Hartung-Knapp adjustments to calculate standardised mean differences. Between-study heterogeneity was examined using Higgins I2 and Cochran Q statistic. Publication bias was assessed using Egger's regression test. This systematic review was registered with PROSPERO, CRD42023397248.

FINDINGS

We identified 9619 studies from our database research and 174 studies from searching relevant systematic reviews and meta-analyses, of which 105 were subjected to full text screening. We included 21 eligible studies, involving 3676 children and adolescents (1618 [44%] were female and 2058 [56%] were male, mean age was 13·7 years [SD 2·7]) in our systematic review and meta-analysis. Ten studies were included in the estimation of the effect of wearable activity trackers on objectively measured daily steps and 11 were included for objectively measured moderate-to-vigorous physical activity. Compared with controls, we found a significant increase in objectively measured daily steps (standardised mean difference 0·37 [95% CI 0·09 to 0·65; p=0·013]; Q 47·60 [p<0·0001]; I2 72·7% [95% CI 53·4 to 84·0]), but not for moderate-to-vigorous physical activity (-0·08 [-0·18 to 0·02; p=0·11]; Q 10·26 [p=0·74]; I2 0·0% [0·0 to 53·6]).

INTERPRETATION

Wearable activity trackers might increase daily steps in young cohorts of various health statuses, but not moderate-to-vigorous physical activity, highlighting the potential of wearable trackers for motivating physical activity in children and adolescents. More rigorously designed trials that minimise missing data are warranted to validate our positive findings on steps and to explore possible long-term effects.

FUNDING

The Hong Kong University Grants Committee and Seed Fund for Basic Research of the University of Hong Kong.

Accelerometer techniques for capturing human movement validated against direct observation: a scoping review

Objective.Accelerometers are devices commonly used to measure human physical activity and sedentary time. Accelerometer capabilities and analytical techniques have evolved rapidly, making it difficult for researchers to keep track of advances and best practices for data processing and analysis. The objective of this scoping review is to determine the existing methods for analyzing accelerometer data for capturing human movement which have been validated against the criterion measure of direct observation.Approach.This scoping review searched 14 academic and 5 grey databases. Two independent raters screened by title and abstract, then full text. Data were extracted using Microsoft Excel and checked by an independent reviewer.Mainresults.The search yielded 1039 papers and the final analysis included 115 papers. A total of 71 unique accelerometer models were used across a total of 4217 participants. While all studies underwent validation from direct observation, most direct observation occurred live (55%) or using recordings (42%). Analysis techniques included machine learning (ML) approaches (22%), the use of existing cut-points (18%), receiver operating characteristic curves to determine cut-points (14%), and other strategies including regressions and non-ML algorithms (8%).Significance.ML techniques are becoming more prevalent and are often used for activity identification. Cut-point methods are still frequently used. Activity intensity is the most assessed activity outcome; however, both the analyses and outcomes assessed vary by wear location. This scoping review provides a comprehensive overview of accelerometer analysis and validation techniques using direct observation and is a useful tool for researchers using accelerometers.

Body Composition and Energy Expenditure in Youth With Spina Bifida: Protocol for a Multisite, Cross-Sectional Study

BACKGROUND

Obesity prevalence in youth with spina bifida is higher than in their typically developing peers. Obesity is associated with lifelong medical, psychological, and economic burdens. Successful prevention or treatment of obesity in individuals with spina bifida is compromised by (1) the lack of valid and reliable methods to identify body fat in a clinical setting and (2) limited data on energy expenditure that are necessary to provide daily caloric recommendations.

OBJECTIVE

The objectives of this study will be to develop 2 algorithms for use in youth with spina bifida in a clinical setting, one to model body fat and one to predict total daily energy expenditure. In addition, physical activity and dietary intake will be described for the sample.

METHODS

This multisite, prospective, national clinical study will enroll 232 youth with myelomeningocele aged 5 to 18 years (stratified by age and mobility). Participants will be enrolled for 1 week. Data obtained include 4 measures of body composition, up to 5 height measures, a ramped activity protocol, and a nutrition and physical activity screener. Participants will wear an accelerometer for the week. On the final study day, 2 samples of urine or saliva, which complete the doubly labeled water protocol, will be obtained. The analysis will include descriptive statistics, Bland-Altman plots, concordance correlation, and regression analysis.

RESULTS

The study received extramural federal funding in July 2019. Data collection was initiated in March 2020. As of April 2024, a total of 143 (female participants: n=76, 53.1%; male participants: n=67, 46.9%) out of 232 participants have been enrolled. Data collection is expected to continue throughout 2024. A no-cost extension until November 2025 will be requested for data analysis and dissemination of findings.

CONCLUSIONS

This study furthers previous pilot work that confirmed the acceptability and feasibility of obtaining alternate height, body composition, and energy expenditure measures. The findings from this study will enhance screening, prevention, and treatment of abnormal weight status by facilitating the accurate identification of youths' weight status category and recommendations of daily caloric needs for this population that is at higher risk of obesity. Furthermore, the findings have the potential to impact outcomes for youth diagnosed with disabilities other than spina bifida who experience similar challenges related to alterations in body composition or fat distribution or measurement challenges secondary to mobility issues or musculoskeletal problems.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

DERR1-10.2196/52779.

The temporal and bi-directional relationship between physical activity and sleep in ambulatory children with cerebral palsy

PURPOSE

Exploring the temporal and bi-directional relationship between device-based measures of physical activity and sleep in ambulatory children with cerebral palsy (CP).

MATERIALS AND METHODS

24-hour activity data were collected from children with CP (n = 51, 43% girls, mean age (range); 6.8 (3-12) years; Gross Motor Function Classification System levels I to III). Nocturnal sleep parameters and daily physical activity were measured for seven consecutive days and nights using ActiGraph GT3X accelerometers. Linear mixed models were constructed to explore the relationships between sleep and activity.

RESULTS

Light and moderate-to-vigorous activity were negatively associated with sleep efficiency (SE) (resp. p = 0.04, p = 0.010) and total sleep time (TST) (resp. p = 0.007, p = 0.016) the following night. Sedentary time was positively associated with SE and TST the following night (resp. p = 0.014, p = 0.004). SE and TST were positively associated with sedentary time (resp. p = 0.011, p = 0.001) and negatively with moderate-to-vigorous physical activity (resp. p < 0.001, p = 0.002) the following day. Total bedtime and TST were negatively associated with light physical activity (resp. p = 0.046, p = 0.004) the following day.

CONCLUSIONS

The findings from this study suggest that ambulatory children with CP may not sleep better after physical activity, and vice versa, indicating that the relationship is complex and needs further investigation.

Reliability and validity of rapid assessment tools for measuring 24-hour movement behaviours in children aged 0-5 years: the Movement Behaviour Questionnaire Baby (MBQ-B) and child (MBQ-C)

BACKGROUND

The development of validated "fit-for-purpose" rapid assessment tools to measure 24-hour movement behaviours in children aged 0-5 years is a research priority. This study evaluated the test-retest reliability and concurrent validity of the open-ended and closed-ended versions of the Movement Behaviour Questionnaire for baby (MBQ-B) and child (MBQ-C).

METHODS

300 parent-child dyads completed the 10-day study protocol (MBQ-B: N = 85; MBQ-C: N = 215). To assess validity, children wore an accelerometer on the non-dominant wrist (ActiGraph GT3X+) for 7 days and parents completed 2 × 24-hour time use diaries (TUDs) recording screen time and sleep on two separate days. For babies (i.e., not yet walking), parents completed 2 × 24-hour TUDs recording tummy time, active play, restrained time, screen time, and sleep on days 2 and 5 of the 7-day monitoring period. To assess test-retest reliability, parents were randomised to complete either the open- or closed-ended versions of the MBQ on day 7 and on day 10. Test-retest intraclass correlation coefficients (ICC's) were calculated using generalized linear mixed models and validity was assessed via Spearman correlations.

RESULTS

Test-retest reliability for the MBQ-B was good to excellent with ICC's ranging from 0.80 to 0.94 and 0.71-0.93 for the open- and closed-ended versions, respectively. For both versions, significant positive correlations were observed between 24-hour diary and MBQ-B reported tummy time, active play, restrained time, screen time, and sleep (rho = 0.39-0.87). Test-retest reliability for the MBQ-C was moderate to excellent with ICC's ranging from 0.68 to 0.98 and 0.44-0.97 for the open- and closed-ended versions, respectively. For both the open- and closed-ended versions, significant positive correlations were observed between 24-hour diary and MBQ-C reported screen time and sleep (rho = 0.44-0.86); and between MBQ-C reported and device-measured time in total activity and energetic play (rho = 0.27-0.42).

CONCLUSIONS

The MBQ-B and MBQ-C are valid and reliable rapid assessment tools for assessing 24-hour movement behaviours in infants, toddlers, and pre-schoolers. Both the open- and closed-ended versions of the MBQ are suitable for research conducted for policy and practice purposes, including the evaluation of scaled-up early obesity prevention programs.

Emerging methods for measuring physical activity using accelerometry in children and adolescents with neuromotor disorders: a narrative review

BACKGROUND

Children and adolescents with neuromotor disorders need regular physical activity to maintain optimal health and functional independence throughout their development. To this end, reliable measures of physical activity are integral to both assessing habitual physical activity and testing the efficacy of the many interventions designed to increase physical activity in these children. Wearable accelerometers have been used for children with neuromotor disorders for decades; however, studies most often use disorder-specific cut points to categorize physical activity intensity, which lack generalizability to a free-living environment. No reviews of accelerometer data processing methods have discussed the novel use of machine learning techniques for monitoring physical activity in children with neuromotor disorders.

METHODS

In this narrative review, we discuss traditional measures of physical activity (including questionnaires and objective accelerometry measures), the limitations of standard analysis for accelerometry in this unique population, and the potential benefits of applying machine learning approaches. We also provide recommendations for using machine learning approaches to monitor physical activity.

CONCLUSIONS

While wearable accelerometers provided a much-needed method to quantify physical activity, standard cut point analyses have limitations in children with neuromotor disorders. Machine learning models are a more robust method of analyzing accelerometer data in pediatric neuromotor disorders and using these methods over disorder-specific cut points is likely to improve accuracy of classifying both type and intensity of physical activity. Notably, there remains a critical need for further development of classifiers for children with more severe motor impairments, preschool aged children, and children in hospital settings.

Motor skill competence and moderate- and vigorous-intensity physical activity: a linear and non-linear cross-sectional analysis of eight pooled trials

BACKGROUND

Few studies have examined the relationship between motor skill competence and device-measured physical activity in large samples and none have used non-linear modelling. This study assessed the linear and non-linear associations between motor skill competence and physical activity in children using pooled data from eight studies.

METHODS

Cross-sectional ActiGraph accelerometer and motor skills competence data from 988 children (50.8% boys) aged 3-11 years were included. Total, object control and locomotor skill competence were assessed using the Test of Gross Motor Skill Development. Linear mixed models were fitted to examine linear associations between motor skill competence and physical activity. Then, restricted cubic splines models were used to assess potential non-linear relationships. Interactions by sex and age were assessed.

RESULTS

There was evidence of positive linear associations between total skill, and object control and locomotor skills, with moderate- and vigorous-intensity physical activity; however, the associations with total skill competence and object control better fitted a non-linear model. Non-linear models indicated associations were positive but relatively weak in the low to mid ranges of TGMD/object control scores but at high ranges (~ > 70 out of 100/ and ~ 35 out of 50) the association strength increased for both moderate- and vigorous-intensity physical activity. There were sex interactions for locomotor skills only, specifically for vigorous activity with boys having a stronger positive association than girls.

CONCLUSIONS

There appears to be a threshold for object control skill proficiency that children need to reach to enhance their physical activity levels which provides support for a motor skill "proficiency barrier". This provides a tangible benchmark for children to achieve in motor competence programs.

Calibration and validation of physical behaviour cut-points using wrist-worn ActiGraphs for children and adolescents: A systematic review

OBJECTIVES

To review cut-points calibrated and independently validated from wrist-worn ActiGraph accelerometers to measure moderate to vigorous physical activity (MVPA) and time spent sedentary (SED) in children and adolescents.

DESIGN

Systematic literature review.

METHODS

Five databases were searched for relevant cut-point calibration and independent validation studies relating to wrist worn ActiGraphs in children and adolescents from inception through 30 April 2022. Extracted data included: country of publication; study name; population; device model; wear location; sampling frequency; epoch length; activity protocol; criterion method and definitions used to classify PA intensity; statistical methods for calibration; statistical methods for validation/cross-validation; and MVPA and SED outcome.

RESULTS

Fourteen calibration studies and seven independent validation studies were identified. Calibrated cut-points for MVPA vector magnitude counts ranged from 7065 to 9204 counts per minute (cpm) and 63.5 to 201 milli-gravitational units (mg). For SED, calibrated cut-points ranged from <2556 cpm to 4350 cpm and 30.8 to 48.1 mg. Classification accuracy values determined by independent validation studies varied, with kappa values ranging from 0.31 to 0.60 and area under the curve statistics ranging from 0.51 to 0.84 for MVPA and kappa values ranging from 0.31 to 0.44 and area under the curve statistics ranging from 0.70 to 0.85 for SED.

CONCLUSIONS

The results of this systematic literature review support the use of the Crouter and colleagues cut-points for the measurement of MVPA and SED for children and adolescents aged 6-12 years. Further work is required to independently validate cut-points developed in younger children and older adolescents.

Development and content validity of an application to assess 24-hour movement behaviors in 0-4-year-old children involving end-users and key stakeholders: the My Little Moves app

BACKGROUND

Recently, research focus has shifted to the combination of all 24-h movement behaviors (physical activity, sedentary behavior and sleep) instead of each behavior separately. Yet, no reliable and valid proxy-report tools exist to assess all these behaviors in 0-4-year-old children. By involving end-users (parents) and key stakeholders (researchers, professionals working with young children), this mixed-methods study aimed to 1) develop a mobile application (app)-based proxy-report tool to assess 24-h movement behaviors in 0-4-year-olds, and 2) examine its content validity.

METHODS

First, we used concept mapping to identify activities 0-4-year-olds engage in. Parents (n = 58) and professionals working with young children (n = 21) generated a list of activities, sorted related activities, and rated the frequency children perform these activities. Second, using multidimensional scaling and cluster analysis, we created activity categories based on the sorted activities of the participants. Third, we developed the My Little Moves app in collaboration with a software developer. Finally, we examined the content validity of the app with parents (n = 14) and researchers (n = 6) using focus groups and individual interviews.

RESULTS

The app has a time-use format in which parents proxy-report the activities of their child, using eight activity categories: personal care, eating/drinking, active transport, passive transport, playing, screen use, sitting/lying calmly, and sleeping. Categories are clarified by providing examples of children's activities. Additionally, 1-4 follow-up questions collect information on intensity (e.g., active or calm), posture, and/or context (e.g., location) of the activity. Parents and researchers considered filling in the app as feasible, taking 10-30 min per day. The activity categories were considered comprehensive, but alternative examples for several activity categories were suggested to increase the comprehensibility and relevance. Some follow-up questions were considered less relevant. These suggestions were adopted in the second version of the My Little Moves app.

CONCLUSIONS

Involving end-users and key stakeholders in the development of the My Little Moves app resulted in a tailored tool to assess 24-h movement behaviors in 0-4-year-olds with adequate content validity. Future studies are needed to evaluate other measurement properties of the app.

A cross-sectional study to compare levels of physical activity among adolescents in rural and urban areas of Western Maharashtra

Background

Childhood and adolescent overweight and obesity has been associated with long term health deterioration. Lack of physical activity in this age group is an important contributing factor towards increase in overweight and obesity. Due to vast socio-cultural differences across India, it is important to assess the patterns of physical activity in different age groups and regions, to understand the differences among adolescents in different socio-geographic regions. However, the studies from India are inconsistent due to use of varied parameters and methodology and a need was felt of incorporating easy to use measures of quantifying physical activity.

Methods

The study was carried out on 416 adolescents (aged 10 to 17 years) from 2 schools each from urban and rural area of Western Maharashtra. The study populations were stratified by gender and age. The data on physical activity was collected using a pre-tested, researcher-administered questionnaire adapted from the Global Physical Activity Questionnaire (GPAQ) and the Physical Activity Questionnaire- Adolescent (PAQ-A).

Results

16.8 percent of rural adolescents did not meet the defined criteria for adequate physical activity as compared to 33.2 percent in the urban population. Urban adolescent population was found to have significantly higher anthropometric measures of adiposity.

Conclusion

Higher proportion of adolescents performing adequate physical activity is likely to be a key factor in keeping the BMI and TMI lower in rural as compared to urban adolescent population.

Raw Acceleration from Wrist- and Hip-Worn Accelerometers Corresponds with Mechanical Loading in Children and Adolescents

The purpose of this study was to investigate associations between peak magnitudes of raw acceleration (g) from wrist- and hip-worn accelerometers and ground reaction force (GRF) variables in a large sample of children and adolescents. A total of 269 participants (127 boys, 142 girls; age: 12.3 ± 2.0 yr) performed walking, running, jumping (<5 cm; >5 cm) and single-leg hopping on a force plate. A GENEActiv accelerometer was worn on the left wrist, and an Actigraph GT3X+ was worn on the right wrist and hip throughout. Mixed-effects linear regression was used to assess the relationships between peak magnitudes of raw acceleration and loading. Raw acceleration from both wrist and hip-worn accelerometers was strongly and significantly associated with loading (all p's < 0.05). Body mass and maturity status (pre/post-PHV) were also significantly associated with loading, whereas age, sex and height were not identified as significant predictors. The final models for the GENEActiv wrist, Actigraph wrist and Actigraph hip explained 81.1%, 81.9% and 79.9% of the variation in loading, respectively. This study demonstrates that wrist- and hip-worn accelerometers that output raw acceleration are appropriate for use to monitor the loading exerted on the skeleton and are able to detect short bursts of high-intensity activity that are pertinent to bone health.

The associations of physical activity, sedentary time, and sleep with V˙O2max in trained and untrained children and adolescents: A novel five-part compositional analysis

The benefits of physical activity (PA) and the negative impacts of sedentary time (SED) on both short- and long-term health in youth are well established. However, uncertainty remains about how PA and SED jointly influence maximal oxygen uptake ([Formula: see text]). Therefore, the aim of this study was to determine the joint influence of PA and SED on [Formula: see text] using compositional analyses. 176 adolescents (84 girls, 13.8 ± 1.8 years) completed an incremental ramp test and supramaximal validation bout on a cycle ergometer, with PA and SED recorded for seven consecutive days on the right hip using a ActiGraph GT3X accelerometer. Time spent in Sleep, SED, light, moderate and vigorous PA was analysed using a compositional linear regression model. Compositions with 10 minutes more time in vigorous PA (> 27.5 mins⋅day-1) compared to the average 17.5 mins⋅day-1 were associated with a + 2.9% - 11.1% higher absolute and scaled [Formula: see text] whilst compositions with less (> -10 mins⋅day-1) VPA were associated with a reduced absolute and allometrically scaled [Formula: see text] (-4.6% - 24.4%). All associations were irrespective of sex, maturity, and training status. The proportion of time spent sedentary had little impact on absolute and scaled [Formula: see text] (0.01-1.98%). These findings therefore highlight that intensity of PA may be of greater importance for increases in [Formula: see text] than reductions in SED and should be incorporated into future intervention designs.

Validation and Determination of Physical Activity Intensity GT3X+ Cut-Points in Children and Adolescents with Physical Disabilities: Preliminary Results in a Cerebral Palsy Population

Background: Children and adolescents with disabilities engage in low levels of moderate-to-vigorous intensity physical activity (MVPA), which may create the onset of a sedentary lifestyle. In light of this, MVPA levels must be quantified with a valid tool such as accelerometry. This study aimed to: (i) analyze the accuracy of Evenson cut-points by estimating MVPA and sedentary behavior (SB) in children and adolescents with disabilities; (ii) define new equations to estimate energy expenditure (EE) with the GT3X+ accelerometer in this population and particularly in those with cerebral palsy (CP); (iii) define specific GT3X+ cut-points to estimate MVPA in those with CP. Methods: A total of 23 children and adolescents with disabilities (10 ± 3 years; 44%females) participated in the study. GT3X+-counts and oxygen uptake (VO2) were measured in four laboratory walking conditions. Results: (i) Evenson cut-points were accurate; (ii) new equations were defined to effectively predict EE; (iii) specific GT3X+ cut-points (VM ≥ 702 counts·min−1; Y-Axis ≥ 360 counts·min−1) were defined for estimating MVPA levels in children and adolescents with CP. Conclusions: The use of specific cut-points for ActiGraph GT3X+ seems to be accurate to estimate MVPA levels in children and adolescents with disabilities and, particularly, in those with CP, at least in laboratory conditions.

A Multi-Component Educational Intervention for Addressing Levels of Physical Activity and Sedentary Behaviors of Schoolchildren

Physical inactivity and a sedentary lifestyle are risk factors for excess weight and obesity in childhood. It is, therefore, necessary to adopt strategies which can modify these behaviors during childhood, the age at which habits are formed. This study aimed to evaluate the impact of an educational intervention using digital media and face-to-face activities involving children, parents, and the school community on the level of physical activity and sedentary behavior among schoolchildren. This was a secondary analysis of data obtained from a community trial in which students from four primary schools in Mexico City participated. Two schools were assigned to the intervention group (IG) and two to the control group (CG). The intervention lasted 12 months and included a face-to-face component, which involved sessions and workshops for parents and children, as well as visual material for children and a distance component utilizing electronic means (web portal and text messages to mobile phones) for parents. Anthropometric measurements were taken and information was collected on moderate to vigorous physical activity performed by the children and on the time that the schoolchildren spent in front of screens at the beginning of the study and at 6 and 12 months. Information on 201 children from the IG and 167 children from the CG was included in the analysis. At 12 months, the IG showed a mean decrease of 33.4 min/d [95% CI: -53.5 to -13.3] in screen time, while the CG showed an increase of 12.5 min/d [CI 95%: -10.5 to 35.6], p = 0.003. After 12 months of follow-up, applying this educational intervention reduced the time that schoolchildren spent in front of screens. Educational intervention is a feasible and accessible strategy for promoting changes in sedentary behaviors in the school-age population.

Start small and let it build; a mixed-method evaluation of a school-based physical activity program, Kilometre Club

BACKGROUND

Despite the benefits of physical activity, there is minimal research focusing on factors that influence real-world school-based physical activity programs. Kilometre (KM) Club is an Australian grassroots program which aims to increase physical activity in students through the completion of an outside walk or run at school. This small-scale pilot evaluation aimed to examine families, teachers and principals' perceptions of the benefits, enablers and barriers of KM Club. It also aimed to examine the effects of KM Club on student's physical activity levels during the school day.

METHODS

Four regional New South Wales (NSW) primary schools participated in this study. 26 families, four teachers, and two principals from School A, C, B and D completed semi-structured interviews to understand their perceptions of KM Club. 21 students completed emotional state-scales to understand their emotions when participating in KM Club. 141 students from Schools B, C and D participated in step-count measures using accelerometers.

RESULTS

Families, teachers and principals reported a range of benefits such as improved social connectedness, wellbeing, home and classroom behaviours, participation in sport and fitness levels. Enablers consisted of champion engagement, incentives, versatile facilities and integration with other school activities. Identified barriers included the weather and environment, program timing and health issues. Most students reported that participating in KM Club made them feel proud, confident and fantastic. School B reported a significant increase in students' daily step counts on KM Club days compared to non-KM Club days (+ 15%; p = 0.001), while School C reported no significant changes (-5%; p = 0.26). School D reported a significant increase in the number of daily steps taken by KM Club participants compared with non-KM club participants (+ 10%; p = 0.024).

CONCLUSION

There is no one-size-fits-all approach to implementing school-based physical activity initiatives. However, it appears that flexible and adaptable factors are important to the successful implementation of school-based programs, such as KM Club. This study revealed a variety of self-reported health, wellbeing and educational benefits for students, as well as an increase in student's physical activity levels at 2 of the 3 schools participating in the quantitative data collection. This pilot evaluation may help to inform future design, implementation and scale-up of KM Club and school-based health promotion programs, potentially improving child health, wellbeing and educational outcomes.

TRIAL REGISTRATION

(LNR223 - LNR/19/NCC/45).

Adolescents' reports of chaos within the family home environment: Investigating associations with lifestyle behaviours and obesity

OBJECTIVE

Disorganised and chaotic home environments may hinder the adoption of healthy lifestyle behaviours and contribute to excessive weight gain among adolescents. We examined whether self-reported level of chaos within the family home environment is associated with lifestyle behaviours and obesity in adolescent girls and boys.

METHODS

Cross-sectional data from the 3rd wave of the Québec Adipose and Lifestyle Investigation in Youth (QUALITY) study were analyzed. The sample consisted of n = 377 White adolescents with a history of parental obesity. Home environment chaos was measured using the Confusion, Hubbub, and Order Scale (CHAOS) analyzed both continuously and dichotomized as high vs. low chaos. Body Mass Index z-scores (zBMI) were computed using WHO standards from measured weight and height. Physical activity (7-day accelerometry), vegetable and fruit intake (three 24-hour diet recalls), and leisure screen time and sleep duration (questionnaire) were assessed. Sex-specific linear regression models were used to estimate associations between level of family home environment chaos, lifestyle behaviours and zBMI.

RESULTS

The overall level of chaos was low in our study sample, with higher reported levels among girls compared to boys. Among girls, high (vs low) chaos was associated with shorter sleep duration (hours/day) (B = - 0.44, 95% CI: -0.75, -0.14). No associations were observed for other lifestyle behaviours or for zBMI.

CONCLUSION

In this sample of adolescents with a parental history of obesity, higher household chaos was not associated with obesity or lifestyle behaviours, except for sleep duration among girls. Replication of findings in more diverse samples is indicated.

A consensus method for estimating physical activity levels in adults using accelerometry

Identifying the best analytical approach for capturing moderate-to-vigorous physical activity (MVPA) using accelerometry is complex but inconsistent approaches employed in research and surveillance limits comparability. We illustrate the use of a consensus method that pools estimates from multiple approaches for characterising MVPA using accelerometry. Participants (n = 30) wore an accelerometer on their right hip during two laboratory visits. Ten individual classification methods estimated minutes of MVPA, including cut-point, two-regression, and machine learning approaches, using open-source count and raw inputs and several epoch lengths. Results were averaged to derive the consensus estimate. Mean MVPA ranged from 33.9-50.4 min across individual methods, but only one (38.9 min) was statistically equivalent to the criterion of direct observation (38.2 min). The consensus estimate (39.2 min) was equivalent to the criterion (even after removal of the one individual method that was equivalent to the criterion), had a smaller mean absolute error (4.2 min) compared to individual methods (4.9-12.3 min), and enabled the estimation of participant-level variance (mean standard deviation: 7.7 min). The consensus method allows for addition/removal of methods depending on data availability or field progression and may improve accuracy and comparability of device-based MVPA estimates while limiting variability due to convergence between estimates.

Exercise intensity of active video gaming in cerebral palsy: hip- versus wrist-worn accelerometer data

OBJECTIVE

The aim of this study was to compare exercise intensity of active video games (AVGs) between hip- and wrist-worn accelerometer data in cerebral palsy (CP).

METHODS

Twenty children and adolescents (9.35 ± 3.71 years) with CP performed two exercise sessions, completing a standardized series of AVGs. Exercise intensity was collected, while one accelerometer was fitted to wrist and hip in separate, counterbalanced sessions.

RESULTS

Accelerometer counts per minute and cut-points determined were significantly different between the wrist- and hip-worn outputs (p < .001). Metabolic equivalents (METs) of performing AVGs exceeded the three METs moderate intensity threshold in wrist-worn (3.12 ± 0.86) accelerometer and hip-worn data tend to underestimate intensity (1.16 ± 0.08).

CONCLUSIONS

Previous studies showed METs required to perform AVGs were related to moderate intensity (3-6 METs) in CP with mild deficits. Wrist-worn accelerometer, exceeding 3 METs, seem to have higher accuracy in measuring exercise intensity of AVGs than hip-worn.

Relations among parent-reported physical activity and interoception in children

BACKGROUND

Interoception is the sense of one's internal body and emotional state; it plays a critical role in guiding self-regulatory behaviors. Physical activity (PA) can support interoceptive processes, but limited research has examined the association in children. This study explored the relations among parent-reported PA and several interoceptive domains in children aged 3 - 10 years old.

METHODS

Baseline data were analyzed from a cluster-randomized controlled study examining a yoga intervention (N = 122). Parents completed a questionnaire that included the Caregiver Questionnaire for Interoceptive Awareness, Second Edition (CQIA-2) and two measures of PA, the PROMIS Parent-Proxy Short Form (PROMIS-PA) and the adapted Burdette Proxy Report (aBPR-PA). Psychometrics of the CQIA-2 subscales were assessed and then used in subsequent analyses to examine the association between PA and interoceptive sensibility.

RESULTS

Seventy percent of the surveys were completed by mothers (30% by fathers), and their children (56% female, M_age = 5.81 ± 1.7 years) were predominately white. Across all children, PA had a significant positive relationship with interoceptive domains related to emotion and physical energy (p < 0.01). Children who met the PROMIS-PA "good" cutoff had a clearer sense of emotion and physical energy (F(2,115) = 4.30, p = 0.016, R² = 0.070), compared to children who did not. Children's age predicted interoceptive sensibility of illness and toileting needs (F(1,116) = 14.16, p < 0.001, R² = 0.109).

CONCLUSION

Children with higher PA levels were perceived to have better interoceptive sensibility of emotion and physical energy. Children's age was predictive of interoceptive domains representing the awareness of illness and toileting needs. Future work should consider incorporating direct measures of PA and child-reported interoceptive sensibility. A better understanding of their relationship will likely help guide the design of more effective interventions for health behavior development.

Accessibility and use of novel methods for predicting physical activity and energy expenditure using accelerometry: a scoping review

Use of raw acceleration data and/or 'novel' analytic approaches like machine learning for physical activity measurement will not be widely implemented if methods are not accessible to researchers.Objective: This scoping review characterizes the validation approach, accessibility and use of novel analytic techniques for classifying energy expenditure and/or physical activity intensity using raw or count-based accelerometer data.Approach: Three databases were searched for articles published between January 2000 and February 2021. Use of each method was coded from a list of citing articles compiled from Google Scholar. Authors' provision of access to the model (e.g., by request, sample code) was recorded.Main Results: Studies (N = 168) included adults (n = 143), and/or children (n = 38). Model use ranged from 0 to 27 uses/year (average 0.83) with 101 models that have never been used. Approximately half of uses occurred in a free-living setting (52%) and/or by other authors (56%). Over half of included articles (n = 107) did not provide complete access to their model. Sixty-one articles provided access to their method by including equations, coefficients, cut-points, or decision trees in the paper (n = 48) and/or by providing access to code (n = 13).Significance: The proliferation of approaches for analyzing accelerometer data outpaces the use of these models in practice. As less than half of the developed models are made accessible, it is unsurprising that so many models are not used by other researchers. We encourage researchers to make their models available and accessible for better harmonization of methods and improved capabilities for device-based physical activity measurement.

Methods for estimating physical activity and energy expenditure using raw accelerometry data or novel analytical approaches: a repository, framework, and reporting guidelines

The proliferation of approaches for analyzing accelerometer data using raw acceleration or novel analytic approaches like machine learning ('novel methods') outpaces their implementation in practice. This may be due to lack of accessibility, either because authors do not provide their developed models or because these models are difficult to find when included as supplementary material. Additionally, when access to a model is provided, authors may not include example data or instructions on how to use the model. This further hinders use by other researchers, particularly those who are not experts in statistics or writing computer code.

OBJECTIVE

We created a repository of novel methods of analyzing accelerometer data for the estimation of energy expenditure and/or physical activity intensity and a framework and reporting guidelines to guide future work.

APPROACH

Methods were identified from a recent scoping review. Available code, models, sample data, and instructions were compiled or created.

MAIN RESULTS

Sixty-three methods are hosted in the repository, in preschoolers (n=6), children/adolescents (n=20), and adults (n=42), using hip (n=45), wrist (n=25), thigh (n=4), chest (n=4), ankle (n=6), other (n=4), or a combination of monitor wear locations (n=9). Fifteen models are implemented in R, while 48 are provided as cut-points, equations, or decision trees.

SIGNIFICANCE

The developed tools should facilitate the use and development of novel methods for analyzing accelerometer data, thus improving data harmonization and consistency across studies. Future advances may involve including models that authors did not link to the original published article or those which identify activity type.

Do Active Commuters Feel More Competent and Vital? A Self-Organizing Maps Analysis in University Students

University students represent a population that faces high risks regarding physical inactivity. Research suggests that a regular engagement in physical activity (PA) may be more likely established when it leads to the experience of subjective vitality. Subjective vitality, in turn, is more likely achieved through physical activities that individuals feel competent in, and that take place in natural outdoor environments. An activity that may fulfill these conditions is active commuting to and from university (ACU). To examine whether and in which form ACU can combine this promising pattern of aspects, a person-oriented analysis was conducted. The sample contained 484 university students (59.3% females). Leisure-time PA, ACU by walking, ACU by cycling, subjective vitality, PA-related competence and body mass index were included as input variables in a self-organizing maps analysis. For both female and male university students, the identified clusters indicated that students who intensively engaged in ACU did not exhibit subjective vitality levels above average. Consistently, they did not show elevated levels of PA-related competence, which suggests that ACU does not support the perception of their physical abilities. Considerations regarding urban university environments lacking sufficient natural elements finally add to the conclusion that engaging in ACU does not suffice to establish a vitality-supportive and thus sustainable PA behavior. Additionally, the identified clusters illustrate a large heterogeneity regarding the interaction between leisure-time PA, body mass index and subjective vitality.

Changes in physical activity across a 6-month weight loss intervention in adolescents with intellectual and developmental disabilities

BACKGROUND

Adolescents and young adults with intellectual and developmental disabilities (IDD) have high rates of obesity and low levels of physical activity. This analysis examined changes in light, moderate-to-vigorous physical activity (MVPA) and sedentary time, and the association between changes in MVPA and weight loss in adolescents and young adults with IDD and overweight and obesity participating in a 6-month multi-component weight loss intervention.

METHODS

Adolescents and young adults with IDD and overweight or obesity (body mass index ≥ 85 percentile, n = 110, age ~16 years, 52.7% female) and a parent were randomised to one of three intervention groups: face-to-face delivery/conventional reduced energy diet (n = 36), remote delivery (RD)/conventional reduced energy diet (n = 39), or RD/reduced energy enhanced stop light diet (eSLD) (n = 35.) Participants were asked to engage in 60 min/day of MVPA on 5 or more days/wk. Participants and a parent attended twice monthly education/behavioural counselling sessions with a health educator to assist participants in complying with dietary and MVPA recommendations. Education/counselling in the RD arms was delivered remotely using video conferencing, and self-monitoring of MVPA and daily steps was completed using a wireless activity tracker. Education/counselling in the face-to-face arm was delivered during home-visits and self-monitoring of MVPA and daily steps was completed by self-report using paper tracking forms designed for individuals with IDD. MVPA, light activity, and sedentary time were assessed over 7 days at baseline and 6 months using a portable accelerometer (ActiGraph wGT3x-BT).

RESULTS

Mixed modelling analysis completed using participants with valid accelerometer data (i.e. ≥4-10 h days) at baseline (n = 68) and 6 months (n = 30) revealed no significant changes in light, moderate- MVPA, or sedentary time across the 6-month intervention (all P > 0.05). Participants obtained 15.2 ± 21.5 min/day of MVPA at baseline and 19.7 ± 19.7 min/day at 6 months (P = 0.119). Mixed modelling indicated no significant effects of group (P = 0.79), time (P = 0.10), or group-by-time interaction (P = 0.21) on changes in MVPA from baseline to 6 months. Correlational analysis conducted on participants with valid accelerometer data at both baseline and 6 months (n = 24) revealed no significant associations between baseline sedentary time (r = 0.10, P = 0.40) and baseline MVPA (r = -0.22, P = 0.30) and change in MVPA across the 6-month intervention. Additionally, attendance at education/counselling sessions (r = 0.26, P = 0.22) and frequency of self-monitoring of MVPA were not significantly associated with change in MVPA from baseline to 6 months (r = 0.26, P = 0.44). Baseline MVPA (r = 0.02, P = 0.92) and change in MVPA from baseline to 6 months (r = 0.13, P = 0.30) were not associated with changes in body weight across the 6-month intervention.

CONCLUSION

We observed a non-significant increase in MVPA (30%), which was not associated with the magnitude of weight loss in a sample of adolescents and young adults with IDD who participated in a 6-month multi-component weight loss intervention. Additional strategies to increase MVPA in adolescents and young adults with IDD participating in weight loss interventions need to be developed and evaluated.

Nature-Based Early Childhood Education and Children's Physical Activity, Sedentary Behavior, Motor Competence, and Other Physical Health Outcomes: A Mixed-Methods Systematic Review

BACKGROUND

The purpose was to synthesize evidence on the association between nature-based Early Childhood Education (ECE) and children's physical activity (PA) and motor competence (MC).

METHODS

A literature search of 9 databases was concluded in August 2020. Studies were eligible if (1) children were aged 2-7 years old and attending ECE, (2) ECE settings integrated nature, and (3) assessed physical outcomes. Two reviewers independently screened full-text articles and assessed study quality. Synthesis was conducted using effect direction (quantitative), thematic analysis (qualitative), and combined using a results-based convergent synthesis.

RESULTS

1370 full-text articles were screened and 39 (31 quantitative and 8 qualitative) studies were eligible; 20 quantitative studies assessed PA and 6 assessed MC. Findings indicated inconsistent associations between nature-based ECE and increased moderate to vigorous PA, and improved speed/agility and object control skills. There were positive associations between nature-based ECE and reduced sedentary time and improved balance. From the qualitative analysis, nature-based ECE affords higher intensity PA and risky play, which could improve some MC domains. The quality of 28/31 studies was weak.

CONCLUSIONS

More controlled experimental designs that describe the dose and quality of nature are needed to better inform the effectiveness of nature-based ECE on PA and MC.

Evaluation of Wrist Accelerometer Cut-Points for Classifying Physical Activity Intensity in Youth

Background

Wrist worn accelerometers are convenient to wear and provide greater compliance. However, methods to transform the resultant output into predictions of physical activity (PA) intensity have been slow to evolve, with most investigators continuing the practice of applying intensity-based thresholds or cut-points. The current study evaluated the classification accuracy of seven sets of previously published youth-specific cut-points for wrist worn ActiGraph accelerometer data.

Methods

Eighteen children and adolescents [mean age (± SD) 14.6 ± 2.4 years, 10 boys, 8 girls] completed 12 standardized activity trials. During each trial, participants wore an ActiGraph GT3X+ tri-axial accelerometer on the wrist and energy expenditure (Youth METs) was measured directly using the Oxycon Mobile portable calorimetry system. Seven previously published sets of ActiGraph cut-points were evaluated: Crouter regression vertical axis, Crouter regression vector magnitude, Crouter ROC curve vertical axis, Crouter ROC curve vector magnitude, Chandler ROC curve vertical axis, Chandler ROC curve vector magnitude, and Hildebrand ENMO. Classification accuracy was evaluated via weighted Kappa. Confusion matrices were generated to summarize classification accuracy and identify patterns of misclassification.

Results

The cut-points exhibited only moderate agreement with directly measured PA intensity, with Kappa ranging from 0.45 to 0.58. Although the cut-points classified sedentary behavior accurately (> 95%), classification accuracy for the light (3-51%), moderate (12-45%), and vigorous-intensity trials (30-88%) was generally poor. All cut-points underestimated the true intensity of the walking trials, with error rates ranging from 35 to 100%, while the intensity of activity trials requiring significant upper body and/or arm movements was consistently overestimated. The Hildebrand cut-points which serve as the default option in the popular GGIR software package misclassified 30% of the light intensity trials as sedentary and underestimated the intensity of moderate and vigorous intensity trials 75% of the time.

Conclusion

Published ActiGraph cut-points for the wrist, developed specifically for school-aged youth, do not provide acceptable classification accuracy for estimating daily time spent in light, moderate, and vigorous intensity physical activity. The development and deployment of more robust accelerometer data reduction methods such as functional data analysis and machine learning approaches continues to be a research priority.

Physical Activity Time and Intensity in Physical Education During the COVID-19 Pandemic

With the COVID-19 outbreak, schools have experienced difficulty providing moderate-to-vigorous physical activity (MVPA) to their students, which should normally account for at least 50% of children’s physical education (PE) class time. We aimed to determine the intensity of physical activity (PA) within PE classes at various grade levels to compare children’s in-class PA with the World Health Organization’s (WHO) recommended guidelines. Thus, 301 students (1st to 12th grade) participated in the investigation. Children were evaluated during the PE classes with different typologies and durations. We assessed PA intensity using accelerometry and grouped data into either sedentary-to-light PA (SEDLI) or MVPA. Each child was assessed using both the time spent in PA (hours:minutes:seconds) and the percentage of time spent in PA versus other class activities. We found that, in the second-grade level group (fifth and sixth grades), girls spent more time in MVPA intensity than boys. Additionally, two-hour PE classes doubled the SEDLI for students in the third-grade group, and polythematic classes (those with more than one sport) promoted more MVPA level time than monothematic classes (only one sport). Concerning PA intensity during PE classes, 31–43% of the PE class total time was spent in MVPA but presented short duration and did not usually persist for 10 consecutive minutes (59% of the time). Children spent a large amount of time at the SEDLI intensity, considered insufficient for PA health benefits. Finally, to meet WHO guidelines for PA intensity, PE classes will need to increase MVPA time and reduce non-active periods between activities.

Bronchiectasis - Exercise as Therapy (BREATH): rationale and study protocol for a multi-center randomized controlled trial

BACKGROUND

Globally, bronchiectasis (BE) unrelated to cystic fibrosis (CF) is recognized as a major cause of respiratory morbidity, mortality, and healthcare utilization. Children with BE regularly experience exacerbations of their condition resulting in frequent hospitalizations and decreased health-related quality of life (HR-QoL). Guidelines for the treatment and management of BE call for regular exercise as a means of improving aerobic fitness and HR-QoL. Moreover, research in adults with BE has shown that exercise can reduce the frequency of exacerbations, a potent predictor of future lung function decline and respiratory morbidity. Yet, to date, the health benefits resulting from therapeutic exercise have not been investigated in children with BE. The BREATH, Bronchiectasis - Exercise as Therapy, trial will test the efficacy of a novel 8-week, play-based therapeutic exercise program to reduce the frequency of acute exacerbations over 12 months in children with BE (aged ≥ 4 and < 13 years). Secondary aims are to determine the cost-effectiveness of the intervention and assess the program's impact on aerobic fitness, fundamental movement skill (FMS) proficiency, habitual physical activity, HR-QoL, and lung function.

METHODS

This multi-center, observer-blinded, parallel-group (1:1 allocation), randomized controlled trial (RCT) will be conducted at three sites. One hundred and seventy-four children ≥ 4 and < 13 years of age with BE will be randomized to a developmentally appropriate, play-based therapeutic exercise program (eight, 60-min weekly sessions, supplemented by a home-based program) or usual care. After completing the baseline assessments, the number of exacerbations and secondary outcomes will be assessed immediately post-intervention, after 6 months of follow-up, and after 12 months of follow-up. Monthly, parental contact and medical review will document acute respiratory exacerbations and parameters for cost-effectiveness outcomes.

DISCUSSION

The BREATH trial is the first fully powered RCT to test the effects of a therapeutic exercise on exacerbation frequency, fitness, movement competence, and HR-QoL in children with bronchiectasis. By implementing a developmentally appropriate, play-based exercise program tailored to the individual needs of children with bronchiectasis, the results have the potential for a major paradigm shift in the way in which therapeutic exercise is prescribed and implemented in children with chronic respiratory conditions. The exercise program can be readily translated. It does not require expensive equipment and can be delivered in a variety of settings, including the participant's home. The program has strong potential for translation to other pediatric patient groups with similar needs for exercise therapy, including those with obesity, childhood cancers, and neurological conditions such as cerebral palsy.

TRIAL REGISTRATION

Australian and New Zealand Clinical Trials Register (ANZCTR) ACTRN12619001008112.

Individual differences in the effects of the ACTION-PAC intervention: an application of personalized medicine in the prevention and treatment of obesity

There is an increased interest in the use of personalized medicine approaches in the prevention or treatment of obesity, however, few studies have used these approaches to identify individual differences in treatment effects. The current study demonstrates the use of the predicted individual treatment effects framework to test for individual differences in the effects of the ACTION-PAC intervention, which targeted the treatment and prevention of obesity in a high school setting. We show how methods for personalized medicine can be used to test for significant individual differences in responses to an intervention and we discuss the potential and limitations of these methods. In our example, 25% of students in the preventive intervention, were predicted to have their BMI z-score reduced by 0.39 or greater, while at other end of the spectrum, 25% were predicted to have their BMI z-score increased by 0.09 or more. In this paper, we demonstrate and discuss the process of using methods for personalized medicine with interventions targeting adiposity and discuss the lessons learned from this application. Ultimately, these methods have the potential to be useful for clinicians and clients in choosing between treatment options, however they are limited in their ability to help researchers understand the mechanisms underlying these predictions.

Physical activity intensity profiles associated with cardiometabolic risk in middle-aged to older men and women

Accelerometers provide detailed data about physical activity (PA) across the full intensity spectrum. However, when examining associations with health, results are often aggregated to only a few summary measures [e.g. time spent "sedentary" or "moderate-to-vigorous" intensity PA]. Using multivariate pattern analysis, which can handle collinear exposure variables, we examined associations between the full PA intensity spectrum and cardiometabolic risk (CMR) in a population-based sample of middle-aged to older adults. Participants (n = 3660; mean ± SD age = 69 ± 8y and BMI = 26.7 ± 4.2 kg/m²; 55% female) from the EPIC-Norfolk study (UK) with valid accelerometry (ActiGraph-GT1M) data were included. We used multivariate pattern analysis with partial least squares regression to examine cross-sectional multivariate associations (r) across the full PA intensity spectrum [minutes/day at 0-5000 counts-per-minute (cpm); 5 s epoch] with a continuous CMR score (reflecting waist, blood pressure, lipid, and glucose metabolism). Models were sex-stratified and adjusted for potential confounders. There was a positive (detrimental) association between PA and CMR at 0-12 cpm (maximally-adjusted r = 0.08 (95%CI 0.06-0.10). PA was negatively (favourably) associated with CMR at all intensities above 13 cpm ranging between r = -0.09 (0.07-0.12) at 800-999 cpm and r = -0.14 (0.11-0.16) at 75-99 and 4000-4999 cpm. The strongest favourable associations were from 50 to 800 cpm (r = 0.10-0.12) in men, but from ≥2500 cpm (r = 0.18-0.20) in women; with higher proportions of model explained variance for women (R² = 7.4% vs. 2.3%). Most of the PA intensity spectrum was beneficially associated with CMR in middle-aged to older adults, even at intensities lower than what has traditionally been considered "sedentary" or "light-intensity" activity. This supports encouragement of PA at almost any intensity in this age-group.

A systematic review of proxy-report questionnaires assessing physical activity, sedentary behavior and/or sleep in young children (aged 0-5 years)

BACKGROUND

Accurate proxy-report questionnaires, adapted to the child's developmental stage, are required to monitor 24-h movement behaviors in young children, especially for large samples and low-resource settings.

OBJECTIVES

This review aimed to summarize available studies evaluating measurement properties of proxy-report questionnaires assessing physical activity, sedentary behavior and/or sleep in children aged 0-5 years.

METHODS

Systematic literature searches were carried out in the PubMed, Embase and SPORTDiscus databases, up to January 2021. For physical activity and sedentary behavior questionnaires this is a review update, whereas for sleep questionnaires we included all relevant studies published up to now. Studies had to evaluate at least one of the measurement properties of a proxy-report questionnaire assessing at least duration and/or frequency of physical activity, sedentary behavior and/or sleep in 0- to 5-year-old children. The COnsensus-based Standards for the selection of health Measurement INstruments (COSMIN) guideline was used to evaluate the quality of evidence.

RESULTS

Thirty-three studies were included, examining a total of 37 questionnaires. Ten questionnaires were designed for infants, two for toddlers, 11 for preschoolers, and 14 for a broader age range targeting multiple of these age groups. Twenty questionnaires assessed constructs of sleep, four assessed constructs of physical activity, two assessed screen behavior, five assessed constructs of both physical activity and sedentary behavior, and six assessed constructs of all 24-h movement behaviors. Content validity was evaluated for six questionnaires, structural validity for two, internal consistency for three, test-retest reliability for 16, measurement error for one, criterion validity for one, and construct validity for 26 questionnaires. None of the questionnaires were considered sufficiently valid and/or reliable for assessing one or more movement behaviors in 0- to 5-year-old children, and the quality of evidence was mostly low or very low.

CONCLUSIONS

Valid and/or reliable questionnaires assessing 24-h movement behaviors in 0- to 5-year-olds are lacking. High-quality studies are therefore required, to develop proxy-report questionnaires and evaluate their measurement properties.

PROSPERO REGISTRATION NUMBER

CRD42020169268.

Perspective: Opportunities and Challenges of Technology Tools in Dietary and Activity Assessment: Bridging Stakeholder Viewpoints

The science and tools of measuring energy intake and output in humans have rapidly advanced in the last decade. Engineered devices such as wearables and sensors, software applications, and Web-based tools are now ubiquitous in both research and consumer environments. The assessment of energy expenditure in particular has progressed from reliance on self-report instruments to advanced technologies requiring collaboration across multiple disciplines, from optics to accelerometry. In contrast, assessing energy intake still heavily relies on self-report mechanisms. Although these tools have improved, moving from paper-based to online reporting, considerable room for refinement remains in existing tools, and great opportunities exist for novel, transformational tools, including those using spectroscopy and chemo-sensing. This report reviews the state of the science, and the opportunities and challenges in existing and emerging technologies, from the perspectives of 3 key stakeholders: researchers, users, and developers. Each stakeholder approaches these tools with unique requirements: researchers are concerned with validity, accuracy, data detail and abundance, and ethical use; users with ease of use and privacy; and developers with high adherence and utilization, intellectual property, licensing rights, and monetization. Cross-cutting concerns include frequent updating and integration of the food and nutrient databases on which assessments rely, improving accessibility and reducing disparities in use, and maintaining reliable technical assistance. These contextual challenges are discussed in terms of opportunities and further steps in the direction of personalized health.

A pragmatic evaluation of the primary school Be Active After-School Activity Programme (Be Active ASAP)

The period after school represents an opportunity to engage children in physical activity (PA) programmes in schools. The purpose of this study was to evaluate the effect of an afterschool programme, delivered in schools, on children's participation in and attitudes to PA. Ten schools took part in this non-randomized controlled trial (five experimental and five control schools). Experimental schools participated in an after-school programme delivered by teachers and parents for 50 min per week. Outcome measures included device-measured PA, self-report youth PA behaviour and parental perceptions of the school environment. Measurements took place at baseline, and mean follow-up was at 10 weeks. Data were collected from 196 participants, with a mean age of 8.1 ± 0.8 years. Mean daily minutes of moderate-to-vigorous physical activity (MVPA) for the entire sample at baseline was 69.9 ± 23.3. While both groups presented a decline in MVPA levels, there was a significant difference in the change from baseline to follow-up (P = 0.043) of min/day MVPA between the control group (-13.2 ± 23.9) and the experimental group (-0.9 ± 25.2). This programme may help maintain MVPA levels, with children exposed to the intervention experiencing a significantly lower decline in MVPA than their control counterparts.

Associations Between Physical Activity and Gross Motor Skills in Parent–Child Dyads

This study examines the associations of physical activity and gross motor skills in parent–child dyads. Parent–child dyads (N = 61, 84% mothers, children aged 8–11 years) participated in this study. Anthropometrics were self-reported through Qualtrics. Physical activity was assessed using accelerometers. Motor skills were measured through four skills: catch, kick, throw, and jump. These skills were assessed using process (i.e., performance criteria of the Test of Gross Motor Development-3) and product (i.e., catch percentage and jump distance) measures. A complete motor skill score was computed by standardizing both process and product scores and summing them. Correlation coefficients and ordinary least square regressions were computed to examine the associations of physical activity and motor skills. Parents’ and children’s moderate to vigorous physical activity were significantly associated (β = 0.30 ± 0.11; p = .008). Parents’ and children’s motor skills were significantly associated (β = 0.46 ± 0.18; p = .012). Understanding parent determinants can support effective interventions targeting children’s low physical activity levels and improving motor competence. Our results highlight the importance of parents’ physical activity and motor skills, which are significantly associated with those of their children. These parent factors may be a key consideration for effective family-based physical activity interventions.

Reference Values for Wristband Accelerometry Data in Children Aged 6-11 Years of Age

OBJECTIVES

Wristband activity trackers (accelerometers) could serve as a convenient monitoring tool to continuously quantify physical activity throughout the day. We aim to provide reference values for the use of these devices in healthy children.

METHODS

Children were recruited at a local school and provided with activity trackers (Fitbit Charge 2). Pupils were instructed to wear devices during all normal daytime activities over a period of 11-15 days. Demographic data, total number of daily steps and heart rate were recorded. In addition, all children/parents were asked to complete a questionnaire providing information about daily physical routine (mode of transport to school, sporting activities as well as sport club memberships).

RESULTS

Three hundred two children (54.6% boys; median age 8.7 years) participated in this prospective study. Median wearing time of the device was 12.1 h/day. Overall, the median daily total step count was 12,095. Median step counts/day were significantly higher in boys compared to girls (13,015 vs. 11,305 steps/day; p < 0.0001). In addition, step counts were significantly higher during the week, compared to weekend days. The effect of age on daily step count was found to be non-linear: the total daily step count increased from 6 to 8.5 years of age, while older children (aged >8.5 years) had lower step counts compared to the younger children. Significant predictors of the daily step count were male gender (+1,324.9 steps, p = 0.0008), mode of transportation to school (walking, bicycle, scooter: +865.5 steps p = 0.049), active membership in a sports club (+1,324.9 steps/day, p = 0.0008), and number of structured units of physical exercise performed (+336.5/per 45 min, p < 0.0001). Severe obesity was associated with a significant reduction in total daily step count (-3037.7 steps/day, p = 0.015).

CONCLUSION

Our prospective cohort study of healthy school children provides reference values for wristband accelerometers in normal individuals. In addition, it clarifies the effect of age, body weight and lifestyle on normal daily step counts in school children. This data should be helpful to judge the degree of physical limitation of patients compared to healthy peers.

New Self-Report Measures of Commuting Behaviors to University and Their Association with Sociodemographic Characteristics

Active commuting provides an opportunity for increased physical activity levels by a simple, inexpensive, and easy way to be incorporated in daily routines and could be considered a steppingstone for achieving a sustainable society since it provides physical, psychological, environmental, and economic benefits. Objective: (a) to describe the commuting patterns to and from university in students regarding gender, (b) to provide new self-report variables to measure the active commuting behavior, and (c) to examine the sociodemographic characteristics associated with commuting behaviors. Material and Methods: A total of 1257 university students (52.4% females) participated (22.4 ± 5.6 years old) from three Chilean universities located in different cities. Results: 56.1% of women and 42.0% men use public bus to and from university. The commuting energy expenditure was higher in active commuting followed by public and private modes of commuting (p < 0.001). The most active commuters were those older (men: OR = 3.637; 95% CI = 1.63, 8.10; women: OR = 8.841; 95% CI = 3.94, 13.78), those who lived in university residence (men: OR = 12.432; 95% CI = 4.39, 35.19; women: OR = 3.952; 95% CI = 1.31, 11.85), belonged to low socioeconomic level (men: OR = 3.820; 95% CI = 1.43, 10.18; women: OR = 4.936; 95% CI = 1.63, 14.90), and to public universities (men: OR = 26.757; 95% CI = 10.63, 67.34; women: OR = 8.029; 95% CI = 3.00, 21.48). Conclusion: The sociodemographic characteristics may influence in the mode of commuting to university. New variables of commuting behaviors may be efficient to quantify the physical activity.

School physical activity policies and associations with physical activity practices and behaviours: A systematic review of the literature

The development and implementation of school policies is considered a key strategy for the promotion of physical activity (PA) in children and adolescents. This study aimed to systematically review and synthesise existing literature focusing on the associations between formal written school-based PA policies and (a) school PA practices and (b) PA behaviours of school-aged children and adolescents. Fifty-one papers reporting on 52 studies met the eligibility criteria. All but two studies were from high income countries, most used cross-sectional designs and demonstrated fair methodological quality, and just over a third examined language aspects of policies. Findings predominantly indicated a lack of or inconclusive associations between the various characteristics examined and PA outcomes. Inconclusive associations were identified between both PA practice and behaviour outcomes and state level policies, policies focusing on PE and school-day PA, and in studies examining language aspects of policies. Inconclusive associations with both types of outcomes were more likely to be identified compared to a lack of associations in studies using self-report measures and in studies not providing information about the quality of exposure and outcome measures used. Overall, findings highlight the need for further research that acknowledges the complex relationship between school policies and PA outcomes and employs robust methodological approaches to enhance our understanding of this area.

A systematic review of the validity, reliability, and feasibility of measurement tools used to assess the physical activity and sedentary behaviour of pre-school aged children

Physical activity (PA) and sedentary behaviour (SB) of pre-school aged children are associated with important health and developmental outcomes. Accurate measurement of these behaviours in young children is critical for research and practice in this area. The aim of this review was to examine the validity, reliability, and feasibility of measurement tools used to assess PA and SB of pre-school aged children.Searches of electronic databases, and manual searching, were conducted to identify articles that examined the measurement properties (validity, reliability or feasibility) of measurement tools used to examine PA and/or SB of pre-school aged children (3-7 years old). Following screening, data were extracted and risk of bias assessment completed on all included articles.A total of 69 articles, describing 75 individual studies were included. Studies assessed measurement tools for PA (n = 27), SB (n = 5), and both PA and SB (n = 43). Outcome measures of PA and SB differed between studies (e.g. moderate to vigorous activity, step count, posture allocation). Most studies examined the measurement properties of one measurement tool only (n = 65). Measurement tools examined included: calorimetry, direct observation, combined heart rate and accelerometry, heart rate monitors, accelerometers, pedometers, and proxy report (parent, carer or teacher reported) measures (questionnaires or diaries). Studies most frequently assessed the validity (criterion and convergent) (n = 65), face and content validity (n = 2), test-retest reliability (n = 10) and intra-instrument reliability (n = 1) of the measurement tools. Feasibility data was abstracted from 41 studies.Multiple measurement tools used to measure PA and SB in pre-school aged children showed some degree of validity, reliability and feasibility, but often for different purposes. Accelerometers, including the Actigraph (in particular GT3X versions), Actical, ActivPAL and Fitbit (Flex and Zip), and proxy reported measurement tools used in combination may be useful for a range of outcome measures, to measure intensity alongside contextual information.

Physical activity behaviour and screen time in Dutch children during the COVID-19 pandemic: Pre-, during- and post-school closures

BACKGROUND

Measures during the COVID-19 pandemic, including the closure of schools and sports facilities, may have lasting impact on the physical activity (PA) of children that persists for a long time.

OBJECTIVE

To investigate the effect of COVID-19 measures on screen time and PA in Dutch children pre-, during- and post-school closures.

METHODS

In cohort A (n = 102, 10.5 ± 3.6 years, 42.4% boys), data on PA and screen time during the lockdown were collected using a questionnaire. In cohort B (n = 131, 10.2 ± 0.9 years, 43.5% boys), data on PA and screen time were collected using a questionnaire and accelerometry 1 year before and after school closure.

RESULTS

In cohort A, 62% reported less total PA. Self-reported screen time on week days increased 34 ± 105 min/d during the lockdown. In cohort B, sedentary time as measured by accelerometry, increased by 45 ± 67 min/d and only 20% reached PA levels of 60 min/d compared to 64% in May 2019. Self-reported screen time increased by 59 ± 112 min/d and 62 ± 130 min/d during week and weekend days, respectively.

CONCLUSIONS

Children were less physically active, and screen time was higher during and after the school closures due to the COVID-19 lockdown. This is alarming as an active lifestyle in children is crucial in preventing chronic diseases such as obesity.

Associations between physical activity, sedentary time and cardiovascular risk factors among Dutch children

Introduction

Physical activity (PA) plays an important role in the prevention of cardiovascular diseases, especially in children. Previous studies which investigated the role of PA and sedentary time (ST) in cardiovascular disease used different measurements and found inconsistent results. The current study used recommended standardized measures and provides an overview of PA and ST among Dutch primary school children and their associations with cardiovascular risk factors.

Methods

503 children (55% girls, mean age (± SD) 10 ± 1y) were included. PA (total PA, lightPA and moderate to vigorous PA (MVPA)) and ST were measured with the Actigraph GT3X accelerometer. PA in different domains was measured with the BAECKE questionnaire. Cardiovascular risk factors included BMI z-score, waist circumference, blood pressure (z-score) and estimated cardiorespiratory fitness (CRF) as measured with the 20 meter shuttle run test.

Results

Children spent 57 ± 20 min/day (8%) on MVPA and 42% of the children reached the MVPA guideline of 60 min/day. Total PA and MVPA (h/day) were negatively associated with BMI z-score (B = -0.452, p = 0.011) and waist circumference (B = -3.553, p = 0.011) and positively associated with CRF (B = 2.527, p = <0.001). ST was positively associated with BMI z-score (B = 0.108, p = 0.048) and waist circumference (B = 0.920, p = 0.033). No significant associations were found between total PA or PA intensities and blood pressure.

Conclusion

This study used standardized measures of PA and therefore created an accurate overview of PA, ST and their associations with cardiovascular risk factors. PA and ST were associated with BMI z-score, waist circumference and CRF. The findings emphasize the importance of promoting MVPA in children, but also highlight the potential benefits of reducing ST to improve cardiovascular risk factors.

Trial registration

ClinicalTrials.gov NCT03440580.

The Importance of Parents' Income and Education Level in Relation to Their Preschool Children's Activity Level at Leisure

Previous research indicate that socioeconomic status positively corresponds with adults’ and adolescents’ physical activity levels. This study investigated the relationship between parents’ education and income, and preschool children’s physical activity level. A total of 244 Norwegian preschool children aged four to six and their parents were enrolled in the study. The children wore an Actigraph GT1M accelerometer for seven consecutive days to measure their physical activity level. Parents completed a questionnaire that provided information about their education level and income level. To examine the relationship between the parents’ education and income and their children’s physical activity level at leisure, the Kruskal-Wallis H test was conducted. The results revealed that neither mothers’ nor fathers’ education level or income, were associated with their children’s minutes in moderate to vigorous physical activity (MVPA) at leisure. The preschool curriculum of Norway may be one explanation why socioeconomic status was not linked to physical activity in this study. Another possibility is that this study was limited to full-time students with two parents. More research is needed to determine whether parent income or education is linked to physical activity among more diverse or older children in Norway.

An Exploration of Child-Staff Interactions That Promote Physical Activity in Pre-School

A previous study identified a significant association between the average physical activity levels of pre-school staff and children during pre-school hours but did not determine if this association was initiated by pre-school staff or children. The present study aimed to explore the interactions between children and staff to better understand the conditions of such a relationship. Observations using the Environment and Policy Assessment and Observation (EPAO) protocol were carried out in three pre-schools, and a focus-group interview and semiformal interviews were conducted with five pre-school staff in one of the three pre-schools to examine the research question. Both the observations and the interview data revealed that physical activity by pre-school staff initiated physical activity among the children. The findings pointing to the importance of pre-school staff as organizers of the physical activity of children and the willingness of staff to join a physical activity initiated by the children also appear to be important. The findings also indicate that most of the physical activity took place outdoors. The study highlights the importance of pre-school staff as major contributors to the physical activity of pre-school children.

Objectively measured physical activity and sedentary time in children with overweight, obesity and morbid obesity: a cross-sectional analysis

Background

Limited physical activity (PA) and a high level of sedentary time (ST) are associated with childhood obesity and are a target for intervention. This study aimed to assess objectively measured PA and ST in Dutch children across weight categories, age groups and sex.

Methods

202 children with overweight, obesity and morbid obesity (55% girls, 12 ± 3y of age, BMI z-score + 3.15 ± 0.73), referred to the Centre for Overweight Adolescents and Children’s Healthcare (COACH, Maastricht UMC+) were included. PA (total PA, light PA and moderate to vigorous PA (MVPA)) and ST were measured with the GT3X Actigraph accelerometer. Wear time validation was set to include at least four days, 480 min/day, including one weekend day.

Results

PA levels in children with morbid obesity were higher compared to children with obesity, also after correction for age and sex (corrected difference (B) 118 counts per minute (cpm), p = .006). ST was lower in children with morbid obesity compared to children with obesity (B − 51 min/day, p = .018). Girls performed significantly less MVPA than boys (B − 11 min/day, p < .001) and for each year increase of age, children performed less PA (B − 46 cpm, p < .001) and ST increased (B 18 min/day, p < .001).

Conclusion

PA and ST is different in subgroups of children with overweight, obesity and morbid obesity, depending on sex, age and overweight severity. In particular, children with obesity perform less PA and more ST compared to children with morbid obesity. Future research could explore the preferences and needs for PA and ST in children in the different weight categories.

Trial registration

The trial is registered with Clinicaltrials.govNCT02091544 at March 19, 2014.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12889-021-11555-5.

Physical Activity and Fatigue in Children With Intestinal Failure on Parenteral Nutrition

OBJECTIVES

With improved survival of children with intestinal failure (IF), it is important to examine the impact on long-term physical function, physical activity (PA), and fatigue and identify clinical factors that may be predictive of impairment.

METHODS

Cross-sectional study in children with IF on parenteral nutrition (PN) compared with healthy age- and sex-matched controls (HCs). Assessments included: Paediatric Quality of Life (PedsQL) Physical Function subscale, PedsQL Multi-Dimensional Fatigue Scale, and PA Perceived Benefits and Barriers scale. PA was measured using an accelerometer. Medical data was collected by chart abstraction.

RESULTS

Participants included 21 children with IF (14 girls), median age 8.33 (interquartile range [IQR] 6.96-11.04) years and 33 HCs (20 boys), 8.25 (6.67-10.79) years. In those with IF, 13 (62%) were born prematurely with a median of 15 (7.5-24.5) in-patient hospitalizations. There was a significant difference (P = 0.033) in mean steps/day in children with IF (9709 +/- 3975) compared with HCs (13104 +/- 5416), and a correlation between moderate-to-vigorous PA and gestational age (r = 0.642, P = 0.010). Child and parent proxy scores indicate poorer physical function and greater fatigue in the IF group, along with a correlation between greater fatigue (r = -0.538, P = 0.012), poorer physical function (r = -0.0650, P = 0.0001) in children with more hospitalizations. Barriers to PA include "I am tired" and "I am worried about my line."

CONCLUSIONS

Children with IF present with lower levels of PA and physical function and greater fatigue compared with their peers. Ongoing development of medical and rehabilitation intervention strategies is vital to optimize outcomes.

Nutritional Status and Implementation of a Nutritional Education Program in Young Female Artistic Gymnasts

Adolescent high-performance gymnasts are considered to be at risk for low energy intake. The aim of the present study was to determine the effects of implementing a nutritional education program during the sports season on the nutritional status and nutrition knowledge of the female artistic gymnasts from the Technification Center of the Balearic Islands (n = 24; age, 14.1 ± 2.3 years). A quasi-experimental intervention design was applied, which consisted of implementing a nutritional education program of seven sessions given during eight months. Measurements of nutritional intake, nutrition knowledge, and anthropometric parameters, as well as hematological and biochemical blood parameters, were performed. Gymnasts reported low energy and carbohydrate intakes, with significant increases during the study (energy, 28.3 ± 1.4 vs. 32.8 ± 1.4 kcal kg⁻¹, p = 0.015, carbohydrate 3.2 ± 0.2 vs. 3.9 ± 0.2 g kg⁻¹, p = 0.004). The average values for parameters such as hemoglobin, ferritin, lipoprotein, and vitamin C and E levels in the plasma were within normal ranges. Low intakes of most of the food groups were observed during the study, with similar initial and final values. Nutrition knowledge did not change as a result of the study (28.0 ± 1.7 vs. 31.1 ± 1.3, p = 0.185). In conclusion, gymnasts reported low energy intakes. However, blood markers and most of the anthropometrical parameters measured were within normal ranges. The nutrition education program implemented did not produce significant improvements in the dietary habits or nutritional knowledge of gymnasts.

Adherence to the 24-hour movement guidelines and adiposity in a cohort of at risk youth: A longitudinal analysis

BACKGROUND

The 24-hour movement guidelines provide recommendations for physical activity, screen time and sleep duration for children.

OBJECTIVES

Describe adherence to the guidelines and their cross-sectional and longitudinal associations with adiposity from childhood to adolescence.

METHODS

Data are from the QUALITY Cohort. Children were followed at 8 to 10 years (childhood; n = 630), 10 to 12 years (early adolescence; n = 564) and 15 to 17 years (adolescence; n = 377). Physical activity, screen time, and sleep duration were measured by accelerometry and questionnaires. Body mass index z-scores (zBMI), waist circumference, waist-to-height ratio and percent body fat were based on clinical measurements. Multiple linear regressions estimated associations.

RESULTS

In childhood, early adolescence and adolescence, 14%, 6%, and 0% of participants met the 24-hour movement guidelines, respectively. Meeting fewer guideline components was cross-sectionally associated with higher adiposity at each visit. Meeting fewer guideline components in childhood was longitudinally associated with higher adiposity at later visits. For example, those meeting none of the guideline components (vs all) in childhood had a 1.66 SD (95% CI: 0.42, 2.89) higher zBMI in early adolescence.

CONCLUSION

Few participants met the guidelines. Not meeting the guidelines in childhood is associated with higher adiposity 2 and 7 years later. Interventions are needed to increase adherence to the 24-hour movement guidelines across childhood and adolescence.

Associations Between Measures of Physical Activity and Muscle Size and Strength: A Systematic Review

Objective

To determine whether physical activity is associated with lower limb muscle size and strength within the general population.

Data Sources

Six databases were systematically searched from inception using 3 main constructs: lower extremity, muscle volume, and muscle strength.

Study Selection

Studies that measured physical activity (using either objective or subjective measurements), lower limb muscle size, and strength were included. Available discrete group data were standardized using previously published age- and sex-specific normative values prior to analysis.

Data Extraction

The final analysis included 47 studies from an initial yield of 5402 studies. Standardized scores for outcome measures were calculated for 97 discrete groups.

Data Synthesis

As anticipated, lower limb muscle size was positively correlated with lower limb muscle strength (r=0.26, P<.01; n=4812). Objectively measured physical activity (ie, accelerometry, pedometry) (n=1944) was positively correlated with both lower limb muscle size (r=0.30, P<.01; n=1626) and lower limb strength (r=0.24, P<.01; n=1869). However, subjectively measured physical activity (ie, questionnaires) (n=3949) was negatively associated with lower limb muscle size (r=–0.59, P<.01; n=3243) and lower limb muscle strength (r=–0.48, P<. 01; n=3882).

Conclusions

This review identified that objective measures of physical activity are moderately associated with lower limb muscle size and muscle strength and can, therefore, be used to predict muscle changes within the lower limbs associated with exercise-based rehabilitation programs.

Physical Activity and the Home Environment of Pre-School-Aged Children in Urban Bangladesh

Physical activity (PA) is a key determinant of health and development, yet few studies have examined PA levels and risk factors for low PA among young children in low- and middle-income countries. This study aimed to describe the PA and sedentary (SED) behavior levels of preschool-aged children in Dhaka, Bangladesh, and to estimate the associations between potential risk factors in the home built environment and moderate to vigorous PA (MVPA). In a sample of preschool-aged children (n = 65) in Dhaka, PA and SED behavior were measured for 7 days using ActiGraph GT3X-BT accelerometers. Characteristics of the home built environment, socioeconomic factors, and anthropometry were also measured. Linear mixed-effects models were used to estimate multivariable-adjusted associations between characteristics of the home environment and MVPA. Preschool-aged children spent a mean (±standard deviation) 421 ± 48 and 82 ± 23 min per day sedentary and in MVPA, respectively. There were no statistically significant associations between factors in the home built environment (indoor area, presence of an open stairwell, and presence of gross motor activity facilitating items) and MVPA. These findings suggest that the studied characteristics of the home built environment may not significantly influence the MVPA observed among preschool-aged children in Dhaka. Future research should focus on other structural and behavioral factors that facilitate PA among young children in dense urban settings.

Effect of School-Based Body Mass Index Reporting in California Public Schools: A Randomized Clinical Trial

IMPORTANCE

Annually, US schools screen millions of students' body mass index (BMI) and report the results to parents, with little experimental evidence on potential benefits and harms.

OBJECTIVE

To determine the impact of school-based BMI reporting on weight status and adverse outcomes (weight stigmatization and weight-related perceptions and behaviors) among a diverse student population.

DESIGN, SETTING, AND PARTICIPANTS

Cluster randomized clinical trial. The Fit Study (2014-2017) randomized 79 California schools to BMI screening and reporting (group 1), BMI screening only (group 2), or control (no BMI screening or reporting [group 3]) in grades 3 to 8. The setting was California elementary and middle schools. Students in grades 3 to 7 at baseline participated for up to 3 years. A modified intent-to-treat protocol was used. Data analysis was conducted from April 13, 2017, to March 26, 2020.

INTERVENTIONS

School staff assessed BMI each spring among students in groups 1 and 2. Parents of students in group 1 were sent a BMI report each fall for up to 2 years.

MAIN OUTCOMES AND MEASURES

Changes in BMI z score and in adverse outcomes (based on surveys conducted each fall among students in grades 4 to 8) from baseline to 1 and 2 years of follow-up.

RESULTS

A total of 28 641 students (14 645 [51.1%] male) in grades 3 to 7 at baseline participated in the study for up to 3 years. Among 6534 of 16 622 students with a baseline BMI in the 85th percentile or higher (39.3%), BMI reporting had no effect on BMI z score change (-0.003; 95% CI, -0.02 to 0.01 at 1 year and 0.01; 95% CI, -0.02 to 0.03 at 2 years). Weight dissatisfaction increased more among students having BMI screened at school (8694 students in groups 1 and 2) than among control participants (5674 students in group 3). Results of the effect of BMI reporting on other adverse outcomes were mixed: compared with the control (group 3), among students weighed at school (groups 1 and 2), weight satisfaction declined more after 2 years (-0.11; 95% CI, -0.18 to -0.05), and peer weight talk increased more after 1 year (0.05; 95% CI, 0.01-0.09); however, concerning weight control behaviors declined more after 1 year (-0.06; 95% CI, -0.10 to -0.02).

CONCLUSIONS AND RELEVANCE

Body mass index reports alone do not improve children's weight status and may decrease weight satisfaction. To improve student health, schools should consider investing resources in evidence-based interventions.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT02088086.