Wikipedia gives the following as an overview of Yoga:
“The origins of Yoga may date back to pre-vedic Indian traditions. The earliest accounts of yoga-practices are to be found in the Buddhist Nikayas. Parallel developments were recorded around 400 CE in the Yoga Sutras of Patanjali, which combines pre–philosophical speculations and diverse ascetic practices of the first millennium BCE with Samkhya-philosophy. Hatha yoga emerged from tantra by the turn of the first millennium. Gurus from India later introduced yoga to the west, following the success of Swami Vivekananda in the late 19th and early 20th century. In the 1980s, yoga became popular as a system of physical exercise across the Western world. This form of yoga is often called Hatha yoga.”
Reactions from Christian denominations have been varied, from rejection of any involvement with Yoga in any form to acceptance of some aspects mainly the physical exercises while warning against the creation of a void within your mind which could result in allowing Satanic indwelling.
In terms of medical viewpoints, they range from concerns about physical injuries [ usually resulting from newcomers trying to do more than their bodies are strong enough to do] to studies about the practice of yoga’s results on depression, blood pressure, cancer, and other medical problems.
It would seem that it is a matter of balance and how knowledgeable/strong one is as a Christian. “Holy Yoga” is defined in the following video. The key is in the statement that in doing this Yoga, your focus is to be totally on Jesus Christ and God. It is not an ‘emptying of your mind’ which can admit other spiritual forces into your life.
The foundational Word that is the underpinning of Holy Yoga:
This video shows a praise/workout session in Holy Yoga:
From my research, a position that seems to encompass the safest and best results is a system called “Praise Moves” developed by Laurette Willis. She has built a system which uses the ‘safest’ yoga poses (minimizing the potential for injury) with Christian worship songs and Bible study. A joyous praise to God.
The following videos present several of the views on Yoga and how it can and/or cannot interface with Christianity: