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Anouk WMC Oortwijn, Guy Plasqui, John J. Reilly, and Anthony D. Okely

Background:

The purpose of this pilot study was to assess the feasibility of a structured activity protocol in a room calorimeter among young children.

Methods:

Five healthy children (age 5.2 ± 0.4 y) performed an activity protocol in a room calorimeter, ranging from sedentary to vigorous-intensity activities. Energy expenditure (EE) was calculated from continuous measurements of O2-consumption and CO2-production using Weir’s formula. Resting EE was defined as EE during the first 30 min of the study where participants were seated while watching television. The children wore an ActiGraph accelerometer on the right and left hip.

Results:

The protocol was well tolerated by all children, and lasted 150 to 175 min. Further, differences were seen in both EE and accelerometer counts across 3 of the 4 activity intensities.

Conclusions:

It is feasible for young children to perform a structured activity protocol in a room calorimeter enhancing the possibility of conducting future studies to cross-validate existing accelerometer prediction equations.

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Kar Hau Chong, Dorothea Dumuid, Dylan P. Cliff, Anne-Maree Parrish, and Anthony D. Okely

Background : Little is known about the influence of 24-hour movement behaviors on children’s psychosocial health when transitioning from primary to secondary school. This study described changes in 24-hour domain-specific movement behavior composition and explored their associations with changes in psychosocial health during this transition. Methods : Data were drawn from the Longitudinal Study of Australian Children. The analytical sample (n = 909) included children who were enrolled in primary school at baseline (2010) and in secondary school at follow-up (2012). Time spent in 8 domains of movement behaviors was derived from the child-completed time-use diaries. Psychosocial health was examined using the self-report version of the Strengths and Difficulties Questionnaires. Analyses included repeated-measures multivariate analysis of variance and compositional regression. Results : Children reported engaging in more social activities and sleeping less over the transition period. Increased time spent in social activities (β ilr  = −0.06, P = .014) and recreational screen use (β ilr  = −0.17, P = .003) (relative to other domains) were associated with decreased prosocial behavior in boys. Changes in movement behavior composition were not associated with changes in girls’ psychosocial health. Conclusion : This study found considerable changes in children’s 24-hour movement behavior composition, but a lack of consistent association with changes in psychosocial health during the primary to secondary school transition.

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Lyndel Hewitt, Anthony D. Okely, Rebecca M. Stanley, Marjika Batterham, and Dylan P. Cliff

Background: Tummy time is recommended by the World Health Organization as part of its global movement guidelines for infant physical activity. To enable objective measurement of tummy time, accelerometer wear and nonwear time requires validation. The purpose of this study was to validate GENEActiv wear and nonwear time for use in infants. Methods: The analysis was conducted on accelerometer data from 32 healthy infants (4–25 wk) wearing a GENEActiv (right hip) while completing a positioning protocol (3 min each position). Direct observation (video) was compared with the accelerometer data. The accelerometer data were analyzed by receiver operating characteristic curves to identify optimal cut points for second-by-second wear and nonwear time. Cut points (accelerometer data) were tested against direct observation to determine performance. Statistical analysis was conducted using leave-one-out validation and Bland–Altman plots. Results: Mean temperature (0.941) and z-axis (0.889) had the greatest area under the receiver operating characteristic curve. Cut points were 25.6°C (temperature) and −0.812g (z-axis) and had high sensitivity (0.84, 95% confidence interval, 0.838–0.842) and specificity (0.948, 95% confidence interval, 0.944–0.948). Conclusions: Analyzing GENEActiv data using temperature (>25.6°C) and z-axis (greater than −0.812g) cut points can be used to determine wear time among infants for the purpose of measuring tummy time.

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Zhiguang Zhang, Eduarda Sousa-Sá, João R. Pereira, Anthony D. Okely, Xiaoqi Feng, and Rute Santos

Background: This study examined the associations between environmental characteristics of early childhood education and care (ECEC) centers and 1-year change in toddlers’ physical activity and sedentary behavior while at the centers. Methods: Data from 292 toddlers from the GET-UP! study were analyzed. Environmental characteristics of ECEC centers were rated using the Infant/Toddler Environment Rating Scale-revised edition at baseline. Children’s physical activity and sedentary behavior in the centers were assessed using activPAL devices, at baseline and at 1-year follow-up. Linear mixed models were performed to examine the associations between the environmental characteristics and change in the proportion of time spent in physical activity and sedentary behavior. Results: Compared with baseline, children spent a higher proportion of time in sedentary behavior (sitting) but a lower proportion of time in standing and physical activity (stepping) while at ECEC centers, at 1-year follow-up. The environmental characteristics “interaction” (B = −1.39; P = .01) and “program structure” (B = −1.15; P = .04) were negatively associated with change in the proportion of time spent in physical activity. Conclusion: Better “interaction” and “program structure” may preclude children’s physical activity from declining over time and may be considered important features to target in future interventions in ECEC centers aiming at promoting active lifestyles.

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Katherine L. Downing, Jo Salmon, Anna Timperio, Trina Hinkley, Dylan P. Cliff, Anthony D. Okely, and Kylie D. Hesketh

Background: Although there is increasing evidence regarding children’s screen time, little is known about children’s sitting. This study aimed to determine the correlates of screen time and sitting in 6- to 8-year-old children. Methods: In 2011–2012, parents in the Healthy Active Preschool and Primary Years (HAPPY) study (n = 498) reported their child’s week/weekend day recreational screen time and potential correlates. ActivPALs measured children’s nonschool sitting. In model 1, linear regression analyses were performed, stratified by sex and week/weekend day and controlling for age, clustered recruitment, and activPAL wear time (for sitting analyses). Correlates significantly associated with screen time or sitting (P < .05) were included in model 2. Results: Children (age 7.6 y) spent 99.6 and 119.3 minutes per day on week and weekend days engaging in screen time and sat for 119.3 and 374.6 minutes per day on week and weekend days, respectively. There were no common correlates for the 2 behaviors. Correlates largely differed by sex and week/weekend day. Modifiable correlates of screen time included television in the child’s bedroom and parental logistic support for, encouragement of, and coparticipation in screen time. Modifiable correlates of sitting included encouragement of and coparticipation in physical activity and provision of toys/equipment for physical activity. Conclusions: Interventions may benefit from including a range of strategies to ensure that all identified correlates are targeted.

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Simone A. Tomaz, Anthony D. Okely, Alastair van Heerden, Khanya Vilakazi, Marie-Louise Samuels, and Catherine E. Draper

Background: In 2018, South Africa developed 24-hour movement behavior guidelines for children from birth to 5 years. This study reports on the stakeholder consultation as part of this development process. Methods: An online survey was completed by 197 participants; 9 focus groups (with parents/caregivers, early childhood development practitioners, and community health workers, total n = 70) were conducted, and a meeting with stakeholders from government and nongovernment organizations (n = 15) was held. Results: In the online survey, stakeholders overwhelmingly agreed with the guidelines (97.0%) and recognized the benefit of putting the guidelines into practice (88.8%). Most online survey respondents (88.3%) reported that the guidelines would benefit all South African children equally. Responses to open-ended questions in the online survey and focus group discussions revealed issues including safety and nutrition of children, perceived parental barriers to using the guidelines, and education. Training and provision of educational materials were identified from all stakeholders as key in the dissemination and implementation of the guidelines. Conclusions: The findings informed the development of the South African 24-hour movement behavior guidelines and revealed several important factors to address in the dissemination and implementation of the guidelines to ensure that they are applicable and equitable in South Africa.

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John J. Reilly, Adrienne R. Hughes, Xanne Janssen, Kathryn R. Hesketh, Sonia Livingstone, Catherine Hill, Ruth Kipping, Catherine E. Draper, Anthony D. Okely, and Anne Martin

Background: This article summarizes the approach taken to develop UK Chief Medical Officers’ physical activity guidelines for the Under 5s, 2019. Methods: The Grading of Recommendations Assessment, Development and Evaluation (GRADE)-Adaptation, Adoption, De Novo Development (ADOLOPMENT) approach was used, based on the guidelines from Canada and Australia, with evidence updated to February 2018. Recommendations were based on the associations between (1) time spent in sleep, sedentary time, physical activity, and 10 health outcomes and (2) time spent in physical activity and sedentary behavior on sleep outcomes (duration and latency). Results: For many outcomes, more time spent in physical activity and sleep (up to a point) was beneficial, as was less time spent in sedentary behavior. The authors present, for the first time, evidence in GRADE format on behavior type–outcome associations for infants, toddlers, and preschoolers. Stakeholders supported all recommendations, but recommendations on sleep and screen time were not accepted by the Chief Medical Officers; UK guidelines will refer only to physical activity. Conclusions: This is the first European use of GRADE-ADOLOPMENT to develop physical activity guidelines. The process is robust, rapid, and inexpensive, but the UK experience illustrates a number of challenges that should help development of physical activity guidelines in future.

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Xanne Janssen, Dylan P. Cliff, John J. Reilly, Trina Hinkley, Rachel A. Jones, Marijka Batterham, Ulf Ekelund, Soren Brage, and Anthony D. Okely

This study examined the classification accuracy of the activPAL, including total time spent sedentary and total number of breaks in sedentary behavior (SB) in 4- to 6-year-old children. Forty children aged 4–6 years (5.3 ± 1.0 years) completed a ~150-min laboratory protocol involving sedentary, light, and moderate- to vigorous-intensity activities. Posture was coded as sit/lie, stand, walk, or other using direct observation. Posture was classified using the activPAL software. Classification accuracy was evaluated using sensitivity, specificity and area under the receiver operating characteristic curve (ROC-AUC). Time spent in each posture and total number of breaks in SB were compared using paired sample t-tests. The activPAL showed good classification accuracy for sitting (ROC-AUC = 0.84) and fair classification accuracy for standing and walking (0.76 and 0.73, respectively). Time spent in sit/lie and stand was overestimated by 5.9% (95% CI = 0.6−11.1%) and 14.8% (11.6−17.9%), respectively; walking was underestimated by 10.0% (−12.9−7.0%). Total number of breaks in SB were significantly overestimated (55 ± 27 over the course of the protocol; p < .01). The activPAL performed well when classifying postures in young children. However, the activPAL has difficulty classifying other postures, such as kneeling. In addition, when predicting time spent in different postures and total number of breaks in SB the activPAL appeared not to be accurate.

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Sanne L.C. Veldman, Rachel A. Jones, Rebecca M. Stanley, Dylan P. Cliff, Stewart A. Vella, Steven J. Howard, Anne-Maree Parrish, and Anthony D. Okely

Background: The aim of this study was to examine the efficacy of an embedded after-school intervention, on promoting physical activity and academic achievement in primary-school-aged children. Methods: This 6-month, 2-arm cluster randomized controlled trial involved 4 after-school centers. Two centers were randomly assigned to the intervention, which involved training the center staff on and implementing structured physical activity (team sports and physical activity sessions for 75 min) and academic enrichment activities (45 min). The activities were implemented 3 afternoons per week for 2.5 hours. The control centers continued their usual after-school care practice. After-school physical activity (accelerometry) and executive functions (working memory, inhibition, and cognitive flexibility) were assessed pre- and postintervention. Results: A total of 60 children were assessed (7.7 [1.8] y; 50% girls) preintervention and postintervention (77% retention rate). Children in the intervention centers spent significantly more time in moderate to vigorous physical activity (adjusted difference = 2.4%; 95% confidence interval, 0.6 to 4.2; P = .026) and scored higher on cognitive flexibility (adjusted difference = 1.9 units; 95% confidence interval, 0.9 to 3.0; P = .009). About 92% of the intervention sessions were implemented. The participation rates varied between 51% and 94%. Conclusion: This after-school intervention was successful at increasing moderate to vigorous physical activity and enhancing cognitive flexibility in children. As the intervention was implemented by the center staff and local university students, further testing for effectiveness and scalability in a larger trial is required.

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Christiana M.T. van Loo, Anthony D. Okely, Marijka Batterham, Tina Hinkley, Ulf Ekelund, Soren Brage, John J. Reilly, Gregory E. Peoples, Rachel Jones, Xanne Janssen, and Dylan P. Cliff

Background:

To validate the activPAL3 algorithm for predicting metabolic equivalents (TAMETs) and classifying MVPA in 5- to 12-year-old children.

Methods:

Fifty-seven children (9.2 ± 2.3y, 49.1% boys) completed 14 activities including sedentary behaviors (SB), light (LPA) and moderate-to-vigorous physical activities (MVPA). Indirect calorimetry (IC) was used as the criterion measure. Analyses included equivalence testing, Bland-Altman procedures and area under the receiver operating curve (ROC-AUC).

Results:

At the group level, TAMETs were significantly equivalent to IC for handheld e-game, writing/coloring, and standing class activity (P < .05). Overall, TAMETs were overestimated for SB (7.9 ± 6.7%) and LPA (1.9 ± 20.2%) and underestimated for MVPA (27.7 ± 26.6%); however, classification accuracy of MVPA was good (ROC-AUC = 0.86). Limits of agreement were wide for all activities, indicating large individual error (SB: −27.6% to 44.7%; LPA: −47.1% to 51.0%; MVPA: −88.8% to 33.9%).

Conclusions:

TAMETs were accurate for some SB and standing, but were overestimated for overall SB and LPA, and underestimated for MVPA. Accuracy for classifying MVPA was, however, acceptable.