TY JOUR TI STRENGTH TRAINING METHODS FOR HIGHLY QUALIFIED SKI JUMPERS KW highly qualified ski jumpers KW strength exercises KW post-activation stimulation method KW unstable force field method JO Scientific notes of P. F. Lesgaft University AU Kryuchkov, A.S. AU Fendel, T.V. AU Avvakumova, I.A. AU Gorbunov, S.A. AU Zubkov, D.A. PY 2023 IS 0 PB National State University of Physical Education, Sports and Health named after P.F. Lesgaft