Dylan P. Cliff and Anthony D. Okely
Yvonne G. Ellis, Dylan P. Cliff, Steven J. Howard, and Anthony D. Okely
Purpose: To examine the acute effects of a reduced sitting day on executive function (EF) and musculoskeletal health in preschoolers. Methods: A sample of 29 children (54% boys; 4–5 y) participated in a randomized cross-over trial. Each child completed 2 protocols, which simulate a day at childcare in random order for 2.5 hours; a typical preschool day (50% sitting) and a reduced preschool day (25% sitting) where most sitting activities were replaced with standing activities. Sitting, standing, and stepping time were objectively assessed using an activPAL accelerometer. EF was evaluated using tablet-based EF assessments (inhibition, working memory, and task shifting). Musculoskeletal health was assessed using a handheld dynamometer and goniometer. Results: Compared with the typical preschool day, the reduced sitting day showed no significant differences for EF scores. Effect sizes for inhibition (d = 0.04), working memory (d = 0.02), and shifting (d = 0.11) were all small. For musculoskeletal health, no significant differences were reported after the reduced preschool day. The effect sizes for the hip extension force, hamstring flexibility, gastrocnemius length, and balancing on 1 leg were all small (d = 0.21, d = 0.25, d = 0.28, and d = 0.28). Conclusions: This study suggests that reducing sitting time is unlikely to result in acute changes in EF and musculoskeletal health among preschoolers.
Rachel A. Jones, Jacque Kelly, Dylan P. Cliff, Marijka Batterham, and Anthony D. Okely
Single sex after-school physical activity programs show potential to prevent unhealthy weight gain. The aim of this study was to assess the acceptability and potential efficacy of single-sex after-school physical activity programs for overweight and at-risk children from low-income communities.
7-month, 2-arm parallel-group, RCT, conducted at an elementary school in a disadvantaged area in Wollongong, Australia (March-November 2010).
20 boys and 17 girls were randomized to intervention (PA) or active comparison groups (HL). Primary outcomes included implementation, acceptability, percentage body fat and BMI z-score.
The PA programs were acceptable with high implementation and enjoyment rates. At 7 months postintervention girls in the PA group displayed greater changes in percentage body fat (adjust diff. = -1.70, [95% CI -3.25, -0.14]; d = -0.83) and BMI z-score (-0.19 [-0.36, -0.03]; d= -1.00). At 7 months boys in the PA group showed greater changes in waist circumference (-3.87 cm [-7.80, 0.15]; d= -0.90) and waist circumference z-score (-0.33 [-0.64, -0.03]; d= -0.98). For both boys’ and girls’ PA groups, changes in adiposity were not maintained at 12-month follow-up.
Single-sex after-school physical activity programs are acceptable and potentially efficacious in preventing unhealthy weight gain among overweight and at-risk children. However improvements are hard to sustain once programs finish operating.
Dylan P. Cliff, Anthony D. Okely, Leif M. Smith, and Kim McKeen
Gender differences in cross-sectional relationships between fundamental movement skill (FMS) subdomains (locomotor skills, object-control skills) and physical activity were examined in preschool children. Forty-six 3- to 5-year-olds (25 boys) had their FMS video assessed (Test of Gross Motor Development II) and their physical activity objectively monitored (Actigraph 7164 accelerometers). Among boys, object-control skills were associated with physical activity and explained 16.9% (p = .024) and 13.7% (p = .049) of the variance in percent of time in moderate-to-vigorous physical activity (MVPA) and total physical activity, respectively, after controlling for age, SES and z-BMI. Locomotor skills were inversely associated with physical activity among girls, and explained 19.2% (p = .023) of the variance in percent of time in MVPA after controlling for confounders. Gender and FMS subdomain may influence the relationship between FMS and physical activity in preschool children.
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.
Anja Groβek, Christiana van Loo, Gregory E. Peoples, Markus Hagenbuchner, Rachel Jones, and Dylan P. Cliff
This study reports energy expenditure (EE) data for lifestyle and ambulatory activities in young children.
Eleven children aged 3 to 6 years (mean age = 4.8 ± 0.9; 55% boys) completed 12 semistructured activities including sedentary behaviors (SB), light (LPA), and moderate-to-vigorous physical activities (MVPA) over 2 laboratory visits while wearing a portable metabolic system to measure EE.
Mean EE values for SB (TV, reading, tablet and toy play) were between 0.9 to 1.1 kcal/min. Standing art had an energy cost that was 1.5 times that of SB (mean = 1.4 kcal/min), whereas bike riding (mean = 2.5 kcal/min) was similar to LPA (cleaning-up, treasure hunt and walking) (mean = 2.3 to 2.5 kcal/min), which had EE that were 2.5 times SB. EE for MVPA (running, active games and obstacle course) was 4.2 times SB (mean = 3.8 to 3.9 kcal/min).
EE values reported in this study can contribute to the limited available data on the energy cost of lifestyle and ambulatory activities in young children.
Byron J. Kemp, Anne-Maree Parrish, Marijka Batterham, and Dylan P. Cliff
Background: Information about the domains of physical activity (PA) that are most prone to decline between late childhood (11 y), early adolescence (13 y), and mid-adolescence (15 y) may support more targeted health promotion strategies. This study explored longitudinal trends in nonorganized PA, organized PA, active transport and active chores/work between childhood and adolescence, and potential sociodemographic moderators of changes. Methods: Data were sourced from the Longitudinal Study of Australian Children (n = 4108). Participation in PA domains was extracted from youth time-use diaries. Potential moderators were sex, Indigenous status, language spoken at home, socioeconomic position, and geographical remoteness. Results: A large quadratic decline in nonorganized PA (−48 min/d, P < .001) was moderated by sex (β = 5.55, P = .047) and home language (β = 8.55, P = .047), with girls (−39 min/d) and those from a non-English speaking background (−46 min/d) declining more between 11 and 13 years. Active chores/work increased between 11 and 13 years (+4 min/d, P < .001) and then stabilized. Active transport increased among boys between 11 and 13 years (+6 min/d, P < .001) and then declined between 13 and 15 years (−4 min/d, P < .001). Organized PA remained stable. Conclusions: The longitudinal decline in PA participation may be lessened by targeting nonorganized PA between childhood and adolescence. Future interventions may target girls or those from non-English speaking backgrounds during this transition.
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 (βilr = −0.06, P = .014) and recreational screen use (βilr = −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.
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.
João R. Pereira, Dylan P. Cliff, Eduarda Sousa-Sá, Zhiguang Zhang, Jade McNeill, Sanne L.C. Veldman, and Rute Santos
Background: This study aimed to understand whether a higher number of sedentary bouts (SED bouts) and higher levels of sedentary time (SED time) occur according to different day types (childcare days, nonchildcare weekdays, and weekends) in Australian toddlers (1–2.99 y) and preschoolers (3–5.99 y). Methods: The SED time and bouts were assessed using ActiGraph GT3X+ accelerometers. The sample was composed of 264 toddlers and 343 preschoolers. The SED bouts and time differences were calculated using linear mixed models. Results: The toddlers’ percentage of SED time was higher on nonchildcare days compared with childcare days (mean difference [MD] = 2.3; 95% confidence interval, 0.7 to 3.9). The toddlers had a higher number of 1- to 4-minute SED bouts on nonchildcare days compared with childcare days. The preschoolers presented higher percentages of SED time during nonchildcare days (MD = 3.1; 95% confidence interval, 1.6 to 4.5) and weekends (MD = 1.9; 95% confidence interval, 0.4 to 3.4) compared with childcare days. The preschoolers presented a higher number of SED bouts (1–4, 5–9, 10–19, and 20–30 min) during nonchildcare days and weekends compared with childcare days. No SED times or bout differences were found between nonchildcare days and weekends, neither SED bouts >30 minutes on toddlers nor on preschoolers. Conclusion: The SED time and bouts seem to be lower during childcare periods, which means that interventions to reduce sedentary time should consider targeting nonchildcare days and weekends.