What is the typical threshold for how far one should stretch in, say, doing a forward bend? There are different levels of discomfort—and I know one should not stretch to the point of pain, but when should one stop stretching? How far should one push themselves when doing some yoga pose?
When you have reached a certain point of stretching a muscle, it will start to tense because of the stretch reflex.
Stop at the first sign of muscle tension and stay there until you can relax, and the tension and discomfort is completely gone. Focusing on slow, smooth breathing helps. Once relaxed, you can go further into the stretch until you feel tension again, stop there, and wait until the tension is gone and you can fully relax into the stretch. Repeat this process until you can not go any further without the muscle tensing. How much tension, you ask - the answer is, any tension, the slightest you can feel. This is relaxed stretching, where tension is your guide, not your goal.
There is another kind of stretching called isometric stretching, where the muscle is tensed voluntarily and then relaxed, until the maximum range of motion is reached. However, isometric stretching is less common in yoga.
There is a misconception that one must push himself at least until a certain point of discomfort in stretching for it to be effective. However, this is counter-productive, as flexibility is mainly regulated by the nervous system and if you are constantly tense, it will not learn to relax the muscle (which is kind of necessary for increased range of motion). The key to effective stretching is following the procedures of relaxed stretching and/or isometric stretching.
As you noted, stretching too far will result in pain and be counterproductive to your goals, but on the opposite end if you don't stretch enough then there is no intensity and no catalyst for change. You need to find your middle ground before pain but after the discomfort that signals the stretch is working.
Every person is different and our experience in stretching is highly variable. Knowing your middle ground is something that only you can determine, and it comes from experience, trial and error, and self-awareness. And note that if you're doing the stretch correctly you will be gaining flexibility which means your middle ground should be progressively improving over time.
Here are some tips:
- Keep your movements slow so you can react to how your body feels as you progress through the stretch.
- Try to push past your initial discomfort, so long as it doesn't result in pain
- Take note of how far you stretched last set, the day before, or even the week before. use that as your benchmark and see if you can go slightly further.