TY JOUR TI Theoretical foundations of the "United front" model for primary school students in China: integration of family and school sports education KW physical education of schoolchildren KW family-school partnership KW "United front" model KW motor activity JO Scientific notes of P. F. Lesgaft University AU Lavruhina, G.M. AU Pan, J.. PY 2026 IS PB National State University of Physical Education, Sports and Health named after P.F. Lesgaft