TY JOUR TI ANALYSIS OF THE FEATURES OF THE ACCELERATION PHASE TECHNIQUE IN SKI JUMPING FOR BOYS AGED 12-14 KW ski jumping KW young skiers-jumpers KW technical readiness KW acceleration stance KW biomechanical analysis JO Scientific notes of P. F. Lesgaft University AU Zakharov, G.G. AU Kotelevskaya, N.B. AU Ivanova, I.G. AU Beleva, A.N. AU Novikova, N.B. PY 2023 IS 0 PB National State University of Physical Education, Sports and Health named after P.F. Lesgaft