What comes to mind when you hear the word stress? Stress often comes with a negative connotation but it also has another meaning.
A quick online search for the definition of stress reveals the definition below as the top result:
Stress: pressure or tension exerted on a material object.
This definition is neither positive or negative - it is merely an applied force.
What Doesn't Kill Us Makes Us Stronger?
There are many things that get stronger with stress. For example, metals like steel become stronger with stress. Bones remodel in response to stress so moderate exercise is recommended for people with osteoporosis to strengthen bones and slow down bone loss. When we go to the gym, we are also stressing our body to certain levels. We may feel sore after but come back stronger eventually.
On the other hand, we lose what we don't use. That lies in evolution as well as atrophy, which refers to the loss or thinning of muscle. Astronauts lose bone and muscle mass in space due to lower gravity. People who have been bedridden for long periods or have sedentary lifestyles also experience atrophy.
Some amounts of stress is thus required for strength to develop. The key lies in finding a suitable amount of stress so that positive benefits can be reaped. Too little or too much stress can both be unhealthy. The former leads to atrophy while the latter can lead to injury.
Stress, Not Stretch
It may be surprising to some people to hear that in Yin Yoga, the preferred term to use isn't stretch. It is stress. Yin Yoga isn't a deep stretch class. Going to end range motion looking for the deepest stretch isn't the purpose of Yin Yoga.
Stress is the tension placed upon the tissues, while stretch is an elongation that might result from stress. Thus, stressing tissues may or may not result in a stretch.
All tissues in the body need a certain amount of stress. That includes our connective tissue which can extend to include fascia, ligaments, bones and joints etc. These are more yin-like while muscles are more yang-like.
The purpose of Yin Yoga practice is to apply a healthy amount of stress to the yin-like tissues so that they become longer, thicker and stronger over time. We aren't trying to stretch ligaments or joint capsules - we are looking to stress them.
We can't isolate muscles and fascia completely because they are inexplicably connected. It is about what we are giving greater focus to. Some of the yang muscles may come along for the ride but in Yin Yoga, we try to keep the muscles relaxed so that more of the stress can go to the yin tissues.
Therefore, one does not need to go to maximum range of motion in Yin to reap the benefits. Finding just the right amount of stress - not too little, not too much - is the key here.
How Much Is Enough?
This will differ from person to person as everyone's body, experience and tolerance level is different. Here are some quick guidelines that one can use to assess:
Do you feel a sensation in the target area you would like to work on? It may feel like a gentle stretch or compression. If no, you may need to adjust the position, change the pose or you may have room to go a little further.
Is there any sharp/electrifying/burning pain? If yes, it is certainly a sign to back off or change position.
Would you be able to stay in the current position comfortably for the next few minutes? If the answer is no, it may be a good sign to back off to a more manageable depth.
How is your breathing? If you are holding your breath or having difficulty taking steady breaths, it is also a sign to decrease the amount of stress applied.
These guidelines are by no means exhaustive. Remember to listen to your body and keep in mind that we are not going for too much or too little - just right would be nice enough.