Hi Jzatopa, Maha and all,
The core AYP practices of Deep Meditation and Spinal Breathing are both global purification practices, focussing on purifying the sushumna nadi and the first 6 major chakras in the subtle nervous system. Samyama also purifies the body in a balanced way, as do the AYP asana sequences which focus on purifying the first major six chakras.
Cosmic Samyama practice works in a similar way to this, working equally on all seven of the major chakras. The mudras and bandhas also work on purifying the central channel, allowing chakras to open and activate in the order that is right for each individual.
This is important, because we do not know which chakra should be activated in which order for any given individual. It could be anything, and will depend on that individual’s unique matrix of obstructions. Activating chakras in the wrong order can be harmful, and lead to an unbalanced state.
The practice of targeted spinal bhastrika is a practice that can be used by advanced practitioners for dealing with specific blockages in the subtle nervous system. Even then it should be used in a measured way, and only once certain pre-requisites have been met:
Now we are going to consider additional applications of bastrika as a discretionary targeted tool. Why?
Sometimes we may run into a really stubborn obstruction somewhere in the body, and with focused bastrika we can put a lot of pressure in a localized area and literally burn the karma away. It is like using laser surgery in a small area of the body. This is in great contrast to the “global” methods of meditation and spinal breathing we use as our core practices.
It is important that we have met the yoga practice and health-related prerequisites for spinal bastrika before we add targeted bastrika. This cannot be over-emphasized. Targeted bastrika is not a shortcut to enlightenment. In fact, it could land us in substantial discomfort if applied prematurely. If we are new to yoga, and try targeted bastrika without the prerequisite global cleansing provided by meditation and spinal breathing, we could create an unpleasant energy imbalance in our nervous system. [Yogani]
If people are mixing AYP practices with spiritual practices from other traditions and other schools of yoga, then it is basically their own experiment and we are not able to predict the long term results of that. See here for more on experimenting with mixing practices between systems: