Someone just asked the question; " why can't I simply do a karate kata or pump some weights or go running in order to balance out the YIN build up from doing all slow Tai Chi forms"?
He asked if those types of exercises would be YANG enough to re-balance rather than learning for instance the Pauchui form, or the Bagua Linear form, or the Wudang Qi Disruptive forms and the list goes on.
The answer is simple in getting a yin and yang harmony. Exercise without any "internal" expression or movement actually blocks Qi. One of the main reasons for this is that most exercises apart from the obvious, running or swimming etc., (provided they are all done with relaxation to allow the body to move freely) is not natural movement. A karate kata for instance is not natural movement so will not allow for a natural flow of Qi throughout the meridians. Any tension without "sung" will create blockages so these exercises aren't actually YANG so will not re-balance the body and give it a yin and yang harmony.
The pauchui forms both from Tai Chi or Bagua Are VERY NATURAL MOVEMENT with each movement formulated to allow the body to move in accordance with the natural flow of energy within the body. Because of the explosive nature of these forms, they will create YANG Qi and therefore will re balance and out of balance body that is too YIN! This is the reason that the explosive forms were created, to balance out the slower forms.
Yang Lu-ch'an's form, however, is perfectly balanced and even has elements within it to make up for the more YANG forms, which is why we would normally practice YLC form AND one or two of the more explosive forms such as Pauchui throughout the day.
If for instance you rise in the morning, feeling a bit down, or lacking of energy, a bit depressed from maybe too much coffee, you would force yourself to perform one of the explosive forms. And sure enough, this is enough to cause the YANG to rise and lift your spirits for the day.
The reason is that the slower movements from these forms cause Yang energy to rise up; the backbone, which is one of the main "classic sayings" from Tai Chi. Then as we fa-jing that energy out, more YANG is forced to rise to replace it and this causes an immediate re balancing of the body and to get a yin and yang harmony.
You will discover that after performing these explosive forms, you will just feel like doing things. Perhaps there has been something that you have been putting off, a song to write, or something purely physical etc. You will then WANT to do it, having some incentive to do that work.
If you allow the YIN to rise, you will just get sicker and sicker until you will no longer even be able to force yourself to perform the explosive forms. This is what happened to great men like Yang Cheng-fu who was so YIN that he died young.
Any of the more explosive forms will work; such as any of the weapons forms, provided they are done in a correct manner, with Sung and looseness, with no appreciable external tension other than that which is required to allow you to move and hold the weapon.
For me, he who is allergic to caffeine, it is like having the high that caffeine gives but without the bad elements of the come down after. The pauchui training and the good effects that it imparts lasts the whole day. You wouldn't do pauchui for instance before going to bed!
There is something for everyone in the area of explosive forms from either Bagua, Tai Chi or Wudang. And I will also add to the list, the Dim-Mak Foundation Forms as they also work to re-balance the YIN and YANG harmony or Qi.