Below are some additional resources for guiding people away from yoga but I wanted to describe what I have come up with to harvest some of what people find beneficial. I have never taken a yoga class. I have read a couple of books by people of faith trying to sell it as something that can be done safely and a couple of books by others that say it is dangerous. Even the two books I read that endeavored to say Christ could be combined were unconvincing to me and had snippets advising caution with regards to spirit stuff.
I grew up playing hockey and still do play at 61. When we start out we always stretch. So my bit that I suggest that is totally safe spiritually and can gain some benefits of being more limber is to do some stretching while praying. I think of a tree swaying in the wind and just gently explore all kinds of limits and directions that my body and limbs can go while either doing my daily prayers or doing a repetitive prayer like I describe in the Jesus Prayer section. And as is recommended in doing the Jesus Prayer, I try do do slower, deeper breathing. Sometimes I am singing/chanting my prayers. I do try to do them out loud although it is usually quietly out loud since it is often early in the morning. I do not try to hold any position as is done in yoga but slowly move gently to the limits of where I can go staying stable so as to not fall over. And like the tree slowly swaying in the wind, my arms are often reaching up but to the Son in this case versus the sun.
I do spend a lot of time on my knees praying still and the majority of my time praying on my knees still. The Reach Pray mode of praying is nice to mix in. Sometimes I do a bit of a combo with some stretching while kneeling.
Back to those guiding us away from yoga and also reiki, I note the following:
I heard Father Chad Ripperger speak once at Holy Rosary Church in Rochester, New Hampshire. He assists healing people from spiritual possession and guided people away from yoga and reiki. Another resource is this bit by Dan Burke. I also found an article where Pope Francis is referenced and another safe alternative discussed. I also received the following book list for guiding us away from yoga for spiritual safety.
Books: Any thing from Fr. Mitch Pacwa
Russell Chandler: Understanding the New Age Movement
Douglas Groothuis: Confronting the New Age Movement
Elliot Miller: A Crash Course in the New Age Movement (highly recommended by Fr. Pacwa)
Karen Hoyt: The New Age Rage (series of articles, also highly recommended)
Randall Baer: Inside the New Age Nightmare