TY JOUR TI MODERN REQUIREMENTS FOR THE FITNESS OF STAYER SWIMMERS KW swimming KW qualified stayer swimmers KW rank structure KW functional condition KW special endurance KW vestibular stability JO Scientific notes of P. F. Lesgaft University AU Karpova, S.N. PY 2023 IS 0 PB National State University of Physical Education, Sports and Health named after P.F. Lesgaft