TY JOUR TI FACTOR STRUCTURE OF INDIVIDUAL PARAMETERS OF RUNNING EFFICIENCY IN QUALIFIED MIDDLE DISTANCE RUNNERS KW middle-distance runners KW factor analysis KW individual factor structure of running efficiency KW energy parameters of running KW biomechanical parameters of running KW neuromuscular parameters of running JO Scientific notes of P. F. Lesgaft University AU Goryainov, D.V. AU Ilicheva, O.V. PY 2023 IS 0 PB National State University of Physical Education, Sports and Health named after P.F. Lesgaft