Tehran University of Medical Sciences Iranian Journal of Public Health 2251-6085 53 1 2024 01 01 Korean Adolescents Before and After COVID-19: Changes in Physical Activity, Mental Health, and Hygiene Management 136 144 Jeonga Kwon Department of Elementary Education, College of First, Korea National University of Education, Cheongju, Korea Young-Vin Kim Department of Sports and Leisure, School of Arts and Health Care, Myongji College, Seoul, Korea 2023 10 03 2024 01 01 x https://ijph.tums.ac.ir/index.php/ijph/article/view/33360 https://ijph.tums.ac.ir/index.php/ijph/article/download/33360/8138