TY JOUR TI OPTIMIZATION OF THE CONTROL OF THE TRAINING PROCESS OF HIGHLY QUALIFIED SWIMMERS BASED ON THE ANALYSIS OF HEART RATE VARIABILITY INDICATORS KW training process KW swimming KW heart rate KW physical activity JO Scientific notes of P. F. Lesgaft University AU Pankov, D.A. AU CHernogorov, D.N. PY 2023 IS 0 PB National State University of Physical Education, Sports and Health named after P.F. Lesgaft