Introduction In France March 14, 2020 a national lockdown was imposed in France for 55 days to prevent the spread of the Covid-19 and all schools were closed. This study aimed to investigate the effects of home confinement as a result of  lockdown on the activity (physical activity and sedentary behaviors), and their determinants, on French children (6-10 years) and adolescents (11-17 years). Methods The National Observatory for Physical Activity and Sedentary behaviors launched an online survey from April 1 st , to May 6 th , 2020 using popular social networks and websites. It compared the level of physical activity (PA), sitting and screen time before and during the lockdown and identified the impact of the initial PA (active vs. inactive), sedentary (high vs. low) profiles of the participants and the housing conditions. Results 6,491 children were included in this study. Initially active children and adolescents decreased their PA more than those initially inactive (p>0.001), while those who met the sitting time recommendations increased more their sitting time during lockdown (p<0.001). The same applies to screen time (p<0.001). Live in urban was associated with a decrease of PA (p<0.001), an increase of their sitting time (p<0.001) and children's screen time (p=0.002) during lockdown. Conclusion This study showed the deleterious effects of confinement caused by lockdown on physical activity and sedentary behaviors. Housing conditions were associated with lifestyle behaviors over this period of lockdown. Future public health policies should consider these results.

The aim of the present study was to evaluate whether the COVID-19-related confinement and social restrictions affected the levels of physical fitness and academic achievement in primary school French children. A total of 206 primary school children (106 before confinements and 100 after restrictions) completed a test battery evaluating their anthropometric characteristics, body compositions, activity preferences, cognitive performances and physical fitness. The performance of the Standing Long Jump was better at T0 (169.9 ± 142.5 cm) compared to T1 (135.2 ± 31.4 cm) (p = 0.0367), and the Medicine Ball Throw performance declined from T0 to T1 (297.3 ± 81.1 cm vs. 249 ± 52 cm; p < 0.0001). Motor skills (26.9 ± 6.2 s vs. 30.9 ± 5.4 s; p < 0.0001), the shuttle-run test (stages completed), Maximal Aerobic Speed, and the estimated VO2max were lower at T1 compared to T0 (p < 0.0001). Executive functioning was found to be greater at T0 compared to T1 (p < 0.0001). Explicit liking or wanting for sedentary or physical activities did not change between T0 and T1. Both overall physical fitness and cognitive performance drastically declined among primary school French children with the COVID-19-related public health restrictions, which reinforces the need to urgently develop preventive strategies in anticipation of further mitigation measures.

The purpose of this systematic review was to examine the effects of active desks in the school setting on sedentary behavior, physical activity, academic achievements and overall health among children and adolescents aged 5–17 years. A systematic literature search was conducted using five databases until October 2020. Twenty-three studies were included. Studies reported an increase of around 36% in energy expenditure for cycling desks and between 15% and 27.7% for upright active desks. Children increased inhibitory control and selective attention capacity while using cycling desks. A heterogeneous quality of design and of results were observed limiting comparisons and conclusions for each active desk. Despite the lack of strong methodology for the included studies, active desks appear to be a promising intervention in classrooms to improve health-related outcomes in children aged 5–17 years. Due to weak methodology, future studies with stronger study designs and methodology are needed to better inform policy and practice about the role of classroom active desks on health-related outcomes in children and adolescents.