Children human 90 child 82 female 71 Humans 69 male 69 Child 64 Male 47 Female 44 adolescent 36 Adolescent 33 preschool child 25 Article 22 Child, Preschool 22 adult 22 article 22 controlled study 22 major clinical study 21 prevalence 17 Physical activity 15 questionnaire 15 Prevalence 14 psychology 13 COVID-19 12 cross-sectional study 12 human experiment 11 infant 11 school child 11 Adolescents 10 Cross-Sectional Studies 10