TY JOUR TI Individual phenotypes of physiological adaptation in adolescent football players under submaximal physical load KW football KW children's sports KW stress test KW functional state of an athlete KW heart rate variability KW fitness KW physical load JO Scientific notes of P. F. Lesgaft University AU Bocharin, I.V. AU Romanova, S.V. AU Arnst, N.V. AU Tarasova, O.A. PY 2026 IS 0 PB National State University of Physical Education, Sports and Health named after P.F. Lesgaft