Amstar:
How do you do Hatha Yoga (the asanas or poses) without incorporating pranayama (the breathing techniques)? I thought both goes together with proper form and technique. Otherwise, you are just doing regular exercises or stretching. Yes, pranayama can be done by itself; but, hatha yoga requires the proper use (or control) of the breath to achieve the ultimate benefit. Then, again, even sitting still to do pranayama is considered an asana (hatha yoga); in fact, this is the ultimate asana and the highest form of hatha yoga: to hold an asana, such as one of the advanced sitting asanas.

There are different breathing techniques used or recommended by different yoga teachers and even in the ancient literature. Some are similar and some different to SFQ. The practice of yoga is an energy system in and of itself; and, as such, when done properly could interfere with the SFQ energy movement. Not that one is good and one less good; it is just like climbing the mountain from different locations and using different vehicles (which is fine), but not if you expect to do both at the same time.

A better approach might be to have a couple of hours rest between doing the different echniques. For example doing one in the morning and the other midday, or something like that.

After 25 years of yoga practice, I still regularly practice yoga. I, also, enjoy and have richly benefitted from SFQ (both the active exercises and the meditation techniques). I, personally, find them to be very much complimentary. However, I don't practice them in tandem.

The practice of yoga takes me into the silence (as Master Lin would call it) and I do not need to re-enter the door, having already entered within. The practice of SFQ takes me into the silence; and, again, I do not need to re-enter this door having already entered within. Both are very powerful: different paths up the same mountain.

I have found the energy movement, patterning and ordering of both to be somewhat different, in a nice kind of way. The easiest and quickest of the two, for me, is SFQ - definately. SFQ (active exercises) is what I'd call a standing or walking meditation, and it accomplishes the job effectively, efficently and quickly. Why? You are using all of your faculties (mind through concentration, body through movement, emotions through smiling and relaxing, and the breath through its breathing technique) simultaneously to sort of trick the mind and go beyond the mind into the silence: it is a multi-faceted assault, and it wins the battle (excuse the violent terminology). I find SFQ more natural and easier, but this is my opinion.

I would say you can practice both and benefit, but try to space them adequately - at least. Remember Master Lin's admonition about mixing energy systems. Some yoga techniques (asanas and pranayamas) might be complimentary and some others less so: there are so many different types now, as is also true for qigong in general.
Love and Light