TY JOUR TI Improving breaststroke swimming speed by developing explosive power of lower limb muscles during the stage of sports specialization KW swimming KW breaststroke KW youth sports KW swimming technique KW explosive power KW strength training JO Scientific notes of P. F. Lesgaft University AU Maretsky, S.Y. PY 2025 IS 0 PB National State University of Physical Education, Sports and Health named after P.F. Lesgaft