Good post here about finding prana to power yoga asanas. Sounds like pretty much the same thing as finding qi to power taijiquan postures (ignoring the martial aspects for the moment).

And another one by the same author on pranayama (seems like qigong):

First, pranayama is one of the eight limbs of the practice of yoga. It means “control of energy.” In most yoga classes in the US, it gets translated as “breath,” and it becomes teachers’ way to keep track of the students’ mindfulness: if the student has lost track of the ujjayi breath pattern (make a Darth Vader-type breath sound, in and out, and you’ll have the basic idea), then the student has also likely lost the mindfulness element of the practice, and the teacher needs to dial back the intensity and re-establish the breath pattern.

But pranayama is more than simply mindful breathing – it’s the practice of using the breath to explore the subtle energy pathways of the body, and it’s learning to harness that energy as desired in life.

and part of the author’s personal account of this experience:

After about 15 minutes, I began to experience the increase of tension and energies in my hands and forearms. The best analogy I can provide is that they felt like capacitors charging up. I began to feel energies in them twitching and flexing the muscles. And as I continued to breathe, the energies in them grew. I had a feeling of deep wellness, while at the same time, I felt quite high.

This roughly sounds like qigong or taijiquan’s qigong aspects, except they do not appear to want to sink qi to the dantian. So far I haven’t been able to find evidence yoga wants to do the microcosmic orbit as they talk more about awakening kundalini and feeling energy traveling from the perineum to the crown chakra (apparently stopping there, not going back down the front channel). Also, the Buddhist idea of non-attachment to these sensations seems counter to having such a goal. It sounds like Taoist qigong, taijiquan, and TCM are much more specific with working with this energy for different purposes (especially in the case of medical qigong, including acupuncture and acupressure). Or yiquan, despite avoiding traditional vocabulary, with its hunyuanli. Anyways, now I am thinking of yoga more and more as a qigong, maybe a precursor or proto-qigong that is more vague in some ways but has more variety (perhaps) in the physical postures and “limbs” that are somewhat out of scope of secular qigong and perhaps in the specific breathing techniques (?). I suppose qigong is in some way pranayama 2.0.