Hi Bagpuss the Gnome,
I got into all of this because of physical pain, so Im keen to find out if Hatha might be a better way to release tension (particularly in the neck and shoulders / trapezius) than the active flow style I do now.
Do you have any experience of the difference?
Yes: I have to do hatha before vinyasa or else I am likely to pull something. Even a tiny little bit of posterior deltoid is giving me a few weeks of difficulty as a result of doing vinyasa without properly working through the body with hatha first.
Flow is continuous, and muscle fibers stay "on-duty" to inform the brain of stretching (muscle receptor endings). During vinyasa, the muscle fibers have "responsibility" for "containing" the stretch. The spindles constantly tell the brain how far out they are stretched in an effort to prevent the body from overdoing it and tearing something.
In a hatha pose, muscle fibers can relax (and this gives the direct feeling of relaxing into the stretch), because, after about two minutes, muscle fibers significantly reduce contractions and defer neuronal communications (which inform the brain of stretching) to an organ in the muscle's tendon (called the Golgi tendon organ). This is why hatha is different from vinyasa. Muscle is actually getting a stretch, which fiber extension endures after the stretch is over (meaning: a long, slow, deep, stretch causes new muscle memory).
Why is that enduring stretch important and noticeable (versus the contractual stretch of vinyasa)? Because when the muscle fibers are stretched out, they don't put unnecessary tensions on the tendons (and tendons are not as flexible as muscles), and the tendons then do not put unnecessary tension on the ligaments (and ligaments are not flexible at all, though they can slide over joints), and, finally, there is no unnecessary tension from combined muscle-tendon-ligament pulling joints together into compression. Lacking constant compression, the soft cartilage can do its job (without having bones pulled too tightly into themselves, shearing joint cartilages more quickly); limbs then move more easily without unnecessarily impeding each other via tensely compressed joints. There are many articles and publications on this.
(I back off the stretch a little if I am not sure if I am overdoing it (i.e., if it is hard to do long, slow, deep breathing then I back off the stretch until I can do long, slow, deep breathing).
I have not considered anicca during stretches (but, sure, I totally agree with that), rather I've spent time with anatta in stretches these past months. If ego-drives cause a person to try to stretch too far and too fast, there can be painless "pops" that quickly become very painful (and enduringly problematic)...in just a few minutes. This can happen to the best-of-the-best, long-term, skilled practitioners. (In lieu of anatta, for disciples of yogic theology, this is can be a practice of Atta, humility, saatva, bhakti (no personal ego) - whatever one prefers).
If you can do both hatha and vinyasa with just breathing evenly through nostrils (i.e., ujjayi, pranayamic), then there are other benefits.
What do you think?