00686naa#a2200169#i#450# EN\\bibl\116491 20260430160630.4 1994-4683 20260429b2026####ek#y0engy0150####ca RU Reliability of executing the "boomerang" element using a ribbon with backward-upward leg swing in rhythmic gymnastics Journal article Moscow National State University of Physical Education, Sports and Health named after P.F. Lesgaft 2026 6 с. Journal article local Художественная гимнастика. 796.412.2 Marhakshinova Viktoriya Nikolaevna uchzapiski.lesgaft.spb.ru