TY JOUR TI FUNCTIONAL CAPABILITIES OF CROSS-COUNTRY SKIERS IN TRANSITION TO THE STAGE OF HIGHER SPORTSMANSHIP KW cross-country skiers KW stage of highly qualified KW sports reserve KW functional properties KW anaerobic exchange threshold JO Scientific notes of P. F. Lesgaft University AU Reutskaya, E.A. AU Mihalev, V.I. PY 2023 IS 0 PB National State University of Physical Education, Sports and Health named after P.F. Lesgaft