Physiology of Yin Yoga
On the physiological level Yin Yoga targets the deeper connective tissue with the intention to strengthen the joints, ligaments and the deep fascial network.
These yin-type tissues, being more plastic in nature, require yin-type exercise à gentler, but long-held stresses.
On the contrary, yang-type tissues like our muscles, require yang-type exercises à rhythmical and repetitive movements with only brief static holds, as we practice in our yang yoga styles (Ashtanga, Vinyasa, Hatha, etc.).
During our Yin practice we are targeting the deeper connective tissues. If our muscles are warm and active (e.g. because we have just done a more active Yang practice, or we have had a physically active day), they are at their longest and will tend to absorb most of the stress of the pose. We want the muscles to be relaxed, and at best, to be cold (best shortly after getting out of bed), so the physical benefits of the yin practice will be greater.
Practicing yin yoga in the evening, might lead to fewer physical benefits, but can have a very balancing and calming effect after an active day (psychological benefit).
Stress vs. Stretch
Stress = the tension that we place upon the tissues
Stretch = elongation that results from the stress
When applying a stress to our yin tissues the intention is not necessarily to stretch these tissues. The stress might result in a lengthening but, let’s say we are targeting the ligaments and joints, we are not trying to stretch them. We are trying to stress them and over time, the tissues may become longer, thicker and stronger.
Physiology more in detail:
Every stress of tissue lowers the tolerance level of that tissue (no matter if that tissue is yang (muscle) or yin (ligaments, joints, deeper fascia)). Initially, through exercise, the tissue becomes weaker. Then, we release the stress, let the tissue rest and, the tissue recovers and becomes stronger. Only through rest, the tolerance level of a tissue can increase above what it was before. It is key that you give your tissue enough time to recover.
During your yin practice we are not trying to go as deep into a posture as you potentially could – rather, we are finding our edge (à the point/zone where you feel considerable resistance) and stay here waiting for the body to open up (or stay exactly where you are; or back out of the posture a little bit). To go deeper into a yin pose generally means that we are increasing the hold time. Time – not intensity – is the key ingredient in yin yoga.
I hope this post helps you understand a little better how the yin yoga practice can work your connective tissues.
If you want to learn more, I recommend Bernie Clark´s book: The complete Guide to Yin Yoga – The Philosophy and Practice of Yin Yoga
If you want to read more about my first thoughts and following experiences with yin yoga, click here.