“Yoga Sūtra Chapter One verse 2 is a Lakṣaṇa Sūtra in that it
describes the characteristics of Yoga as Citta Vṛtti Nirodha.”
– TKV Desikachar

“The Āsana in which you sit can alter the characteristics of the breath.”
– TKV Desikachar 1980

“My extensive study of Āsana with TKV Desikachar was shaped around forming a deep appreciation of specific core principles that underpin the planning and practice of Āsana and their application to the individual student’s constitution, psychology and need.
Amongst these dozen or so core principles, the first group I studied when looking at any Āsana in depth, were the concepts of Nāma, Rūpa and Lakṣaṇa, or the name, the form and the characteristics of that particular Āsana.
Obviously the Nāma is a useful tag point for identification and the Rūpa is vital as a reference point for the Sat Viniyoga or appropriate application of the Āsana within overall considerations around direction and outcome such as the Śikṣaṇa Krama, Rakṣaṇa Krama or Cikitsā Krama application of the forms used.
However I do feel these days that our understanding in Āsana practice is dominated by the Nāma and the Rūpa with little emphasis on the Lakṣaṇa or inherent characteristics of the Āsana and how understanding this aspect can have a profound effect on the approach, application and outcome of the overall or accumulative impact of the Āsana within the student’s practice.
The teaching of Krishnamacharya around Āsana included an in-depth appreciation of the Lakṣaṇa, especially around the thirty or so primary Āsana such as Jaṭhara Parivṛtti, Bhujaṅgāsana or Januśīrṣāsana.”

“Forward Bends are back stretching Āsana in terms of Bhāvana.
Thus in Paścimatāna Āsana one of the foci is on avoiding pushing
from the lower back as you bend forward.
Thus move forward from the abdominal area by drawing it back,
to encourage the lower back to respond by lengthening.
If we push from the lower back in forward bends,
such as Paścimatānāsana, it can tighten this area,
thus inhibiting the focus on the quality of the Apāna Lakṣaṇa,
as well as transferring stress to the sacrum, hips and hamstrings.”

“As a teacher it can be helpful to consider Āsana as
vehicles to transmit the fundamental principles of practice.
For example a cardinal principle of practice is that Āsana
have a primary and a secondary aspect within their Lakṣana.
Thus we must inquire into what is the primary aspect in this Āsana,
and what is the secondary aspect in this particular Āsana?
The idea is to maintain the integrity of the primary characteristics.
Thus we may need to compromise the secondary characteristics.
For example in Uttānāsana to sustain the primary work in the spine
we can consider a secondary compromise by releasing the knees.”

Links to Related Posts:

A sample Parivṛtti and Paścimatāna Themed Group Practice

Nāma, Rūpa, Lakṣana – The Name, Form and Characteristics of Āsana