My friend Claudia gives a nice intro to the story of the text over on her blog
Chapter II Viniyoga
To make available to all the different parts of Yoga, the proper method of using them this chapter called viniyoga is presented by Nathamuni.
The methods of the eight parts of yoga practice are of three types; early stage of life, steady part of life and end of life.
Srishtikrama is for Brahmacharis (bachelors(, sthiti is for family people and the laya krama is for sanyasis or renouncee Yogis. Yoga should be learnt according to the stage of life.
Srishtikrama is that method which helps to strengthen the muscles, the senses and strength to the body.
Up to the age of 25, one is called a Brahmachari. This is applicable to those who engage in the orthodox study of the Vedas. For the rest such classifications are unclear.
Brahmacharis are those who at the proper age get initiated into the studies of the scriptures and learn the branch of Vedas to which they traditionally belong to.
Such Brahmacharis must pactise the different angas of Yoga daily for the strengthening of memory of the Vedas studied and for the nourishment of the body and the senses.
The student,living in the ashram of the Guru should practice the angas of Yoga to be free of diseases, and other impediments for studies.
The student under the guidance of the teacher should practice yoga regularly in an orderly manner, for the proper development of the body, senses and the kosas/ internal vital organs.
He should focus on such practices that strengthen the brain, generative organs and the senses of sight,smell,taste,touch and hearing.
￼One whose inhalation and exhalation rae of equl duration and long and even, has no fear of death.
One who can exhibit this quality of inhalation in lying sitting asanas and also in pranayama practice need not fear death.
It is the excess of medhas (fat) and mamsa(flesh) inside and outside the body which block the movement of prana in the nadis, kosas, granthis and joints.
All those that help to increase the length, evenness and ease of the breath should be practiced regularly.
The scriptures aver that the position of prana, mind, the soul and the Supreme Lord are one and the same—the heart. ( II-31)
After meditating on the Lord, the Compassionate One, and surrendering everything to Him, one should start Chikitsa routine.
One should practice sthitikrama until one is 75 years old whether single or married.
For a householder practicing Yoga is difficult not possible to get it properly as the family one’s life is full of obstacles.
The whole world knows that the housewife is the protector of the world undoubtedly. She gives education, food, wealth and place to live.
The housewives so fully occupied in taking care of children, grandchildren, relatives, others in want, dependents, household animals and others. But they have little time to take care of themselves.
￼Under such circumstances, how can women who are always occupied practice yoga? But then without them,life in this world is like flowers in the sky. (Impossile)
It is therefore necessary for women to practice a few angas of yoga with discipline, for the protection of the entire family.
They may also follow the proper dharma constantly and consistent with their asrama and varna to please the Lord.
They must cleanse the body consistent with their own family tradition, even at the risk of being criticized by others.
For householders, who should practice the sthiti krama, Pranayamais most important. This is my view.
By practice of Pranayama the dross of the nadisare eliminated from the body through the many channels.
It can be concluded that the toxins in the body are removed if one’s inhalation exhalation and retention are long even and effortless.
Due to proper regulation of the breath, the impurities are removed> then the householder attains clarity of the mind. II 48)
In Pranayama, are well known anuloma, pratiloma and viloma methods. Then it includes internal and external holding of breath.
Pranayama if done with Mula, uddiyana and Jalandhara bandhas is capable of completely uprooting all ailments.
The three bandhas are to be practiced only before taking food. One should lift the mula after exhalation and hold it firmly.
Then one should do Uddiyana bandha and thereafter Jalandharabandha. Then one can do inhalation.
Pranayama is also classified in two ways, Samavritti and vishamavritti depending on the duration of inhalation, exhalation and breathholding.
For starters, sama vritti pranayama is comfortable. The length of exhalation, inhalation and breathholding depends on one’s capacity.
￼Forceful breath work is detrimental to Prana, the life force. Therefore before teaching pranayama one should assess the capacity/ limitations of the learner.
Whether sama vritti or vishama vritti is practiced, the practitioner should oneself carefully follow, test and verify with clarity.
One who follows the path of yoga should practice the part of yoga called pranayama before dawn, at noon, by sunset and even midnight.
The directions of the teacher should be carefully followed by the learner, never inconsistent with tradition, whether one does samantraka or amantraka pranayama. !
It is known as vishama vritii when the duration of each aspect of pranayama is varied. The ratio of 1 to 4 to 2 for inhalation, breathholding and exhalation is the best.
This method of cleansing the nadis is acceptable for all yogis for long. With cleared nadis the prana moves freely and can do its work properly.
Ujjayi, Nadisodhana, Suryabhedha and sitali have been approved by many.
Pranayama practice done in a disciplined way will help remove ailments o bladder, liver, spleen, diaphragm and heart.
Also they will have a long life, have a steady mind provided they surrender to the lotus feet of the Lord.
The central teaching of Upanishad is the integrated approach of wisdom and action. This is possible if one has firm and healthy body (with the Lord) in the heart.