Background: Little is known about the combined effect of physical activity (PA), recreational screen time (ST), and sleep in preventing childhood obesity. Hence, this study aimed to analyze the associations between meeting the PA, ST, and sleep recommendations within the 24-hour movement guidelines and adiposity indicators among children and adolescents. Methods: A total of 679 children and adolescents aged 8-18 years were included. The time spent in moderate-tovigorous PA and the sleep duration were estimated from raw data from a wrist-worn accelerometer. Recreational ST was reported by the child or parent. Body mass index (BMI) z-score, fat mass percentage (FM%), and visceral adipose tissue (VAT) were used as adiposity indicators. Participants with ≥ 60 min/day of moderate-to-vigorous PA, < 2 h/day of recreational ST, and uninterrupted sleep for 9-11 h/day (for children) or 8-10 h/day (for adolescents) were considered to meet the overall 24-hour movement guidelines. Results: Meeting the ST only recommendation was associated with reduced odds of a high BMI z-score (odds ratio [OR] = 0.38, 95% confidence interval [CI]: 0.17-0.89), excess FM% (OR = 0.34, 95% CI: 0.13-0.93), and excess VAT (OR = 0.27, 95% CI: 0.10-0.74) in adolescents. Significantly reduced odds of a high BMI z-score was associated with meeting the combination of the ST and sleep recommendations (OR = 0.11, 95% CI: 0.01-0.89). Adolescents who met one recommendation (OR = 0.51, 95% CI: 0.27-0.96) or any two recommendations (OR = 0.33, 95% CI: 0.11-0.94) had reduced ORs of having a high BMI z-score. Adolescents had lower odds of having excess VAT if they met one recommendation (OR = 0.39, 95% CI: 0.19-0.81) or any two recommendations (OR = 0.25, 95% CI: 0.07-0.90). No significant associations were found in children. Conclusions: The present study showed no associations between meeting all three recommendations within the 24-hour movement guidelines and adiposity indicators. However, meeting ST only recommendation and the combination of the ST and sleep recommendations was associated with a reduced risk of excess adiposity. This finding should be considered when designing effective strategies and interventions to prevent childhood obesity.

Although there is an increasing awareness of the suitability of using compositional data methodology in public health research, classical methods of statistical analysis have been primarily used so far. The present study aims to illustrate the potential of robust statistics to model movement behaviour using Czech adolescent data. We investigated: (1) the inter-relationship between various physical activity (PA) intensities, extended to model relationships by age; and (2) the associations between adolescents’ PA and sedentary behavior (SB) structure and obesity. These research questions were addressed using three different types of compositional regression analysis—compositional covariates, compositional response, and regression between compositional parts. Robust counterparts of classical regression methods were used to lessen the influence of possible outliers. We outlined the differences in both classical and robust methods of compositional data analysis. There was a pattern in Czech adolescents’ movement/non-movement behavior—extensive SB was related to higher amounts of light-intensity PA, and vigorous PA ratios formed the main source of potential aberrant observations; aging is associated with more SB and vigorous PA at the expense of light-intensity PA and moderate-intensity PA. The robust counterparts indicated that they might provide more stable estimates in the presence of outlying observations. The findings suggested that replacing time spent in SB with vigorous PA may be a powerful tool against adolescents’ obesity.

Active commuting (AC) to school represents a great opportunity to incorporate walking or cycling into adolescents’ everyday routine. The objective of the study was to describe changes in AC in Czech adolescents across a 10-year period in different built environments. Data from the 2001 and 2011 Czech Census of Population and Housing were used to examine the mode of transportation taken to school in 6236 adolescents. Changes in AC over time were analyzed for low and high walkable areas separately in two Czech regional cities, Olomouc and Hradec Králové. Between 2001 and 2011, the proportion of adolescents actively commuting to school decreased by 47%, from an absolute rate of 49.1% to 26%. The proportion of active commuters fell in low walkable areas by 61% and in high walkable areas by 39%. The results indicated that adolescents in 2011 were 2.7 times less (OR = 0.365, p < 0.001) likely to actively commute than in 2001. The AC behavior in Czech adolescents has a negative tendency to replicate travel-to-school patterns in adolescents previously described in more developed countries. The findings might serve as a recommendation for municipal policy.

Background To examine compositional associations between short sleep duration and sedentary behavior (SB), light physical activity (LPA) and moderate-to-vigorous physical activity (MVPA) among children and adolescents. Methods Multi-day 24-h data on sleep, SB, LPA and MVPA were collected using accelerometers among 343 children (8–13 years old) and 316 adolescents (14–18 years old). Children and adolescents with sleep duration of < 9 and < 8 h, respectively, were classified as short sleepers. Robust compositional regression analysis was used to examine the associations between short sleep duration and the waking-time composition. Results Seventy-one percent of children and 75.3% of adolescents were classified as short sleepers. In children, being a short sleeper was associated with higher SB by 95 min/day ( p < 0.001) and lower MVPA by 16 min/day ( p = 0.002). Specifically, it was associated with a higher amount of time spent in long sedentary bouts (β ilr1 = 0.46, 95% confidence interval [CI] = 0.29 to 0.62) and lower amounts of time spent in sporadic SB (β ilr1 = − 0.17, 95% CI = –0.24 to − 0.10), sporadic LPA (β ilr1 = − 0.09, 95% CI = –0.14 to − 0.04) and sporadic MVPA (β ilr1 = − 0.17, 95% CI = –0.25 to − 0.10, p < 0.001 for all), relative to the remaining behaviours. In adolescents, being a short sleeper was associated with a higher amount of time spent in SB by 67 min/day ( p = 0.001) and lower LPA by 2 min/day ( p = 0.035). Specifically, it was associated with more time spent in sedentary bouts of 1–9 min (β ilr1 = 0.08, 95% CI = 0.02 to 0.14, p = 0.007) and 10–29 min (β ilr1 = 0.10, 95% CI = 0.02 to 0.18, p = 0.015), relative to the remaining behaviours. Conclusions Among children and adolescents, short sleep duration seems to be highly prevalent and associated with less healthy waking time. Public health interventions and strategies to tackle the high prevalence of short sleep duration among children and adolescents are warranted.