en پژوهشي Research <span style="font-size:9pt"><span minion="" pro="" style="font-family:"><b>Introduction</b>: The COVID-19 pandemic allowed us to test the relationship between lifestyle changes and children&#39;s motor proficiency level, And by preventing the decrease in movement skills, we should predict the necessary programs to improve the health of children and students during epidemics. The purpose of this research was to investigate the relationship between physical activity and nutritional knowledge with body mass index (BMI) and motor skills of girls aged 10 to 14 years.</span></span><br> <span style="font-size:9pt"><span minion="" pro="" style="font-family:"><b>Materials & Methods</b><b><span style="font-size:11.0pt"><span new="" roman="" style="font-family:" times="">: </span></span></b>The research was correlational-descriptive with a cross-sectional way. The statistical population was 350 selected girls aged 10 to 14 years in schools in Khanaqin city, which were randomly selected as the research sample. In this study, the Bruininks Oseretsky test-Short Form (BOT-2), International Physical Activity Questionnaire (IPAQ), and the Eating Habits Questionnaire (EHQ) were used to collect data. Data analysis was carried out using Pearson&rsquo;s correlation coefficient to SPSS V.21 at the P<0.05.<span lang="FA" dir="RTL" style="font-family:"Times New Roman","serif""></span></span></span><br> <span style="font-size:9pt"><span minion="" pro="" style="font-family:"><b>Results</b><b><span style="font-size:11.0pt"><span new="" roman="" style="font-family:" times="">: &nbsp;</span></span></b>Physical activity correlated negatively (r=-0.29, p=0.01) with BMI and correlated positively with motor proficiency (r= 0.213, p=0.05), but there is no significant relationship between nutritional knowledge with BMI and motor proficiency of girls aged 10 to 14 years old in the schools of Khanaqin during the Corona era.</span></span><br> <span style="font-size:9pt"><span minion="" pro="" style="font-family:"><b>Conclusion</b><b><span style="font-size:11.0pt"><span new="" roman="" style="font-family:" times="">: &nbsp;</span></span></b>Physical activity during the Corona period improves the BMI and motor skills in girls. Therefore, to have a positive effect on motor skills, it is necessary to choose appropriate physical activities according to the situation and perform them regularly.</span></span><br> &nbsp; Body Mass Index, COVID-19, Motor Proficiency, Nutritional Status, Sports 56 64 http://jbrms.medilam.ac.ir/browse.php?a_code=A-10-916-1&slc_lang=en&sid=1 Shevan Fazel Hasan shevanshevan301@gmail.com 10031947532846008329 0009-0000-7469-3346 No Department of Sports Science, Faculty of Literature and Humanities, Ilam University, Ilam, Iran Maryam Naghibzadeh m.naghibzadeh@ilam.ac.ir 10031947532846008330 10031947532846008330 Yes Department of Sports Science, Faculty of Literature and Humanities, Ilam University, Ilam, Iran Sobhan Hadidi roozbahani949@gmail.com 10031947532846008331 0009-0006-6456-363X No Department of Sports Science, Faculty of Literature and Humanities, Ilam University, Ilam, Iran