Given the negative outcomes associated with smartphone use during personal and relational activities (SUPRA), parents strive to regulate its use among their children. However, media parenting recommendations lack knowledge of parental views on SUPRA and their relative occurrence in youths. This study aimed to (i) estimate SUPRA frequency among children and adolescents, (ii) assess parental dislike (PD) of SUPRA, and (iii) identify predictors of PD of SUPRA. An online survey was completed by 826 parents (49% mothers, age 25-74, Median = 43 years), capturing PD of SUPRA, estimated frequency of SUPRA in their children (49% female, age 6-18, Median = 10 years), parenting styles (warmth and control), parental attitudes toward screen media, and sociodemographic characteristics. The rate of frequent SUPRA was significantly higher in adolescents (2.7-48.1%) compared to children (2.1-27.2%) with odds ratios ranging from 0.67 to 3.04, depending on the activity type. PD of SUPRA was high in parents of children (M = 4.04, SD = 0.66) and adolescents (M = 3.93, SD = 0.71). Linear regression identified being a mother, having higher levels of control and warmth, and less positive attitudes toward screen media as significant predictors of SUPRA dislike. Our study was the first to report the estimated occurrence and parental dislike of smartphone use (SU) during various personal and relational activities, enabling their direct comparison. Experts warn against SU while studying and at bedtime, which frequently occurred in 4-5% of children and 10-12% of adolescents. More attention should be paid to SU during relational (peer/family) activities due to its relatively high occurrence and parental dissatisfaction.

• MeSH
• chytrý telefon * MeSH
• dítě MeSH
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• mladiství MeSH
• postoj MeSH
• průzkumy a dotazníky MeSH
• rodiče * psychologie   MeSH
• rodičovství * psychologie   MeSH
• senioři MeSH
• vztahy mezi rodiči a dětmi MeSH
• Check Tag
• dítě MeSH
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• mladiství MeSH
• mužské pohlaví MeSH
• senioři MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH

BACKGROUND: The lockdown measures related to coronavirus disease 2019 (COVID) impacted the health of adolescents by reducing physical activity (PA). The physical changes in response to decreases in PA can be measured with full body composition analysis. The aim of this study was to evaluate the effects of long-term PA restrictions on body fat (BF), fat-free mass (FFM) and skeletal muscle mass (SMM) in adolescents. METHODS: A total of 1669 boys (before PA restriction (G1): 998; after PA restrictions ended (G2): 671; between the ages of 11 and 18 were included. The measured parameters were body mass (BM), visceral fat area (VFA), BF, FFM and SMM. The whole-body composition was evaluated using bioelectrical impedance analysis (BIA). RESULTS: Compared to G1, G2 exhibited an increase in BF between 1.2 and 5.1%. This difference was significant in boys aged 13 to 18 years (p < 0.05). VFA increased between 5.3 and 20.5 cm2; this increase was significant in boys aged 13 to 18 years (p < 0.05). SMM decreased between 2.6 and 3.8%, and this decrease was significant in all age groups (p < 0.05). Changes in body composition were not accompanied by any significant changes in BM. CONCLUSIONS: COVID-19 restrictions reduced PA, resulting in a significant decrease in SMM. This decrease may impact boys' ability to engage in sufficiently varied PA, which may lead to a further decline in PA and subsequent medical consequences in adulthood.

• Klíčová slova
• Body fat, Body mass, Fat-free mass, Physical activity restriction, Skeletal muscle mass, Visceral fat,
• MeSH
• COVID-19 * epidemiologie   MeSH
• dítě MeSH
• dospělí MeSH
• kontrola infekčních nemocí MeSH
• lidé MeSH
• mladiství MeSH
• složení těla MeSH
• tuková tkáň MeSH
• Check Tag
• dítě MeSH
• dospělí MeSH
• lidé MeSH
• mladiství MeSH
• mužské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Geografické názvy
• Česká republika epidemiologie   MeSH

BACKGROUND: Little is known on how context-specific sedentary behaviors (SB) affect adiposity. This study aimed to investigate compositional associations between context-specific SB and adiposity and estimate the differences in adiposity associated with replacing school and out-of-school SB with physical activity (PA). METHODS: This study included 336 children and adolescents. Time spent in SB and PA was estimated using multi-day 24-hour raw accelerometer data. SB and PA were specified for school and out-of-school times. Fat mass percentage (FM%) and fat mass index (FMI) were used as adiposity indicators. A compositional isotemporal substitution model was used to estimate differences in adiposity associated with one-to-one reallocations of time from context-specific SB to PA. RESULTS: Participants spent approximately two thirds of their school and out-of-school time being sedentary. Relative to the remaining 24-h movement behaviors, significant associations between out-of-school SB and adiposity were found in both boys (βilr1 = 0.63, 95% confidence interval [CI] = 0.03-1.22 for FM%; βilr1 = 0.76, 95% CI = 0.03-1.49 for FMI) and girls (βilr1 = 0.62, 95% CI = 0.25-0.98 for FM%; βilr1 = 0.80, 95% CI = 0.28-1.32 for FMI). Replacing 30 min/day of out-of-school SB with out-of-school light PA decreased FM% by 10.1% (95% CI = 3.3-17.9) and FMI by 14% (95% CI = 2.7-24) in girls. No significant associations were found for school SB. CONCLUSIONS: A reduction of out-of-school SB in favor of light PA should be advocated as an appropriate target for interventions and strategies to prevent childhood obesity.

• Klíčová slova
• Accelerometry, Compositional data analysis, Schools, Time-use epidemiology,
• MeSH
• adipozita * MeSH
• akcelerometrie MeSH
• cvičení * MeSH
• dítě MeSH
• lidé MeSH
• mladiství MeSH
• sedavý životní styl * MeSH
• školy MeSH
• Check Tag
• dítě MeSH
• lidé MeSH
• mladiství MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• Geografické názvy
• Česká republika MeSH