Your comment is evidence of a very common misunderstanding of yoga, equating the whole practice a an equivalency to asana/postures.  A profound bow, done mindfully is a version of ardha uttanasana. Rosary is mantra practice. Both the Rosary and the Liturgy of the Hours focus mind and regulate breath (pranayama) and heart rate. Samadhi can be understood as contemplative prayer.  "Yoga citta vrtti nirodah." (Yoga is the containment of the fluctuations of the mind.")  Yoga has to do primarily with the focusing of the mind. The Yoga Sutra-s mention Isvara, but does not define that concept theologically.  You may find Thomas Ryan, C.S.P.'s work helpful in addressing yoga ad Christian meditation.  As for idolatry, the Yoga Sutras have a good deal to say about harmful attachment and the mind.  Given that grace builds on nature, and yoga is about understanding and mastering an aspect of the natural, there is nothing idolatrous about yoga---unless one mistakes the path for the end.