Hi all,
I thought I’d share my experience as someone who came to AYP from Tai Chi/qigong (I credit my recognizing the value of AYP to having been taught a technique similar to spinal breathing by a qigong teacher).
As Yogani says, Tai Chi is actually a martial art originally, and the style I practice, Chen style, is still relatively “martial” in its emphasis, including both slow and fast movements, as well as an emphasis on a “coiling” coordination of the joints called “silk-reeling energy.” The most popular style of Tai Chi is called Yang style (and there are yet others, such as Wu), which is performed entirely slowly, with an emphasis on relaxation and groundedness. I have not practiced Yang or other styles much, but I can imagine it would be grounding for the reasons Yogani mentions. But, as Yogani mentions, it is probably better and easier to learn and practice it in a group setting, as is most common in Chinese communities, as the social aspect would probably enhance the grounding, and a coach can correct your posture, remind you to relax, etc.
Personally, I have not found much need to use martial arts for grounding because I find long walks are very grounding and sufficient for me, though my martial arts practice, including Chen Tai Chi, may be somewhat grounding as well. Chen Tai Chi, and probably to some extent, all forms of Tai Chi, also have the added benefit of becoming more interesting and, I think, beneficial/powerful as your inner awareness develops because the movements depend on subtle bodily awareness. It is a good form of exercise and even can function as a martial art depending on how you learn it but also probably not necessary for most who can take long walks (then again, there may be cases, like Yogani and his wife’s where it is better for a variety of reasons, perhaps including the social).
Neigong and qigong are really different terms for the same thing, though they vary quite a lot in terms of what is actually done. Some are more similar to Yoga asanas in emphasizing stretching, others are more like moving pranayama, in that the focus is on breath and energy. Although some forms, such as “standing like a post” (zhanzhuang) may be grounding, I think of qigong as primarily stimulating of energies in a manner similar to pranayama, so most versions of it are probably not the ideal choice if the goal is grounding.