The COVID-19 outbreak and svift policy response affected the everyday lives of youth in Serbia, challenging their mental well-being. Aiming to examine the relationship between physical activity level (PAL) and mental well-being of adolescents during the strictest lockdown in Serbia, in April 2020, we analyzed data collected through the national online survey (N = 3089). According to the self-reported moderate-to-vigorous physical activity (MVPA), participants were divided into three groups: 1) engaged in MVPA for at least 60 minutes every day; 2) engaged in MVPA for at least 60 minutes on 4-6 days per week; and 3) engaged in the same amount of MVPA on 0-3 days per week. Mental well-being measures included life satisfaction, self-rated health, and health complaints. An one-way ANOVA detected a significant effect of adolescents’ PAL on their life satisfaction, F(3,27) = 49.64, p = 0.000. The Tukey test showed that the mean life satisfaction was significantly higher in the most active group (M = 8.66, SD = 1.56) than in the moderately active group (M = 8.27, SD = 1.56), and the least active group (M = 7.93, SD = 1.76). The chi-square tests revealed significant associations between adolescents’ PAL and health complaints; less active adolescents were more likely to experience symptoms like headache, nervousness, feeling low, irritability, sleep difficulties, and dizziness (p ≤  0.00). They also experienced multiple health complaints more frequently and self-rated their health less favorably. Therefore, physical activity should be promoted as a protective factor for adolescents’ mental well-being, particularly in emergencies. 

Nutritional status is a relevant indicator of optimal growth and development, as well as the health status of children. Since nutritional status can influence the expression of children’s motor capacities, a study has been carried out in order to examine differences in motor abilities of children in relation to their nutritional status. The sample included 300 first- and second-grade students (132 boys, 168 girls). Students’ motor literacy and motor ability status was evaluated by reduced version of “EUROFIT” test battery, while nutritional status was evaluated based on the body mass index. IOTF criteria were used in order to assign participants into four distinctive groups – underweight, normal weight, overweight and obese. Differences between groups in motor ability status were tested by Kruskal-Wallis and Mann-Whitney tests. No significant differences were found between groups of a different nutritional status in most of the motor abilities, suggesting that BMI does not represent a high-quality predictor of motor abilities of children of lower elementary school grades.