Q. Is one is allowed to practice yoga if all of the Hindu aspects and associations are removed?
A. Rabbinical authorities of our times have addressed the permissibility of the practice of yoga. In essence, yoga involves a blend of physical and a meditative exercises. If done in a Halachik correct fashion there is no reason why it would not be permitted, as the Lubavitcher Rebeh Zt"l pointed out on Tamuz 5739. In practice however, that may be difficult to achieve. You require the proper instructor or teaching method, one that will not engage in religious mantras, meditative ideas or names of postures that identify with an avoido-zoro or their believes, even if one does not personally believe in them.(Bemaareh Habazak 2,56). It can not be done in a mixed group as there are issues of Tznius (modesty) too.
Rabbi A. Bartfeld as advised by Horav Shlomo Miller Shlit"a