The muscles’ relaxation characteristics improvement of belt wrestlers using exercises on the basis of the instantaneous simulatorsRadik Valinurov, Yuriy Denisenko, Aydar Akhmetov, Irek Gilmutdinov and Natalya SeliverstovaBIO Web Conf., 26 (2020) 00070DOI: https://doi.org/10.1051/bioconf/20202600070