Polevoy G. ARTICLE RETRACTED DUE TO PLAGIARISM BY THE AUTHOR Períodos sensibles de desarrollo de la flexibilidad en la edad escolar (Sensitive periods of flexibility development at school age): ARTICLE RETRACTED DUE TO PLAGIARISM BY THE AUTHOR. Retos. 2024;56:1066-1074. doi:10.47197/retos.v56.106243