I am still not sure what you are asking, but I will try to help. But first let me clarify some terms.
Technically, in Yin Yoga we apply a stress to our tissues. We don't "stretch" them. Stretching may happen as a result of the stress, but that is not quite the intent. The more accurate term is "strain" rather than "stretch". A strain is the amount of elongation in a tissue as a result of stress. When we stress our connective tissues, we create a physiological reaction at the cellular level that results in the body making the tissues we just stressed stronger, and perhaps longer. In this way, by stressing the tissues appropriately, we can increase the strength of those tissues and increase the range of motion over time. It is this "over time" that is critical. We don't really want to stretch or strain the ligaments or joint capsules during one particular yin yoga session but over a number of sessions these tissues will elongate.
Contrast this with what happens when we "stretch" our muscles. In this case the stress we apply does result in a strain right away. That is good and it is what the muscles like and need.
So, when you ask "is stretching a way to build yin energy?" I have to say that we don't actually try to stretch our connective tissues in a Yin Yoga practice, at least not in any one class, but rather gradually over a number of classes. Again, technically, we stress these tissues rather than stretch them.
Your second term that is not clear is "yin energy". Yin and yang are relative terms and need a context to properly understand them. In terms of energy, yin would be less energetic, cooler, dimmer, etc while yang would be more energetic, hotter, brighter, etc. The type of energy is not yin or yang but each energy form can be more yin or more yang. For example, if the energy you are referring to is temperature, yin would be cool and yang would be hot. Yin yoga will cool your temperature, so in that way Yin Yoga will create yin temperature. If the energy you are referring to is light, yin will be dark and yang will be bright. Again, Yin Yoga can reduce the brightness.
I suspect, however, this is not really what you are asking. Can you please try to rephrase your question one more time?
If what your asking is about the Yin Yoga practice of stressing the tissues and you are simply asking, will the practice of Yin Yoga increase yin, you will have to tell me which aspect of the body you are referring to. Yin Yoga will calm your mind; thus this more yin in the mind compared to an active yang mind. However Yin Yoga will reduce contraction of the joints; this means we are reducing the yin of the joints rather than increasing them, because we are creating more opening in the joints. Yin Yoga will increase the density of the bones: that is more yin compared to hollower bones. Yin Yoga will increase hydration of the tissues: more water is yin so we are increasing yin in this way. Hopefully you can see my difficulty in understanding what you are asking. Whether the result of our practice is more yin or more yang depends upon what tissues or areas you are considering. I can say, it is all good!
Last edited by Bernie
on Fri Feb 19, 2010 4:12 am, edited 1 time in total.