Krishnamacharya Yoga is grounded in Patanjali’s description of asana as sthira and sukham: steadiness and ease. While many approaches to asana encourage students to push hard, the Krishnamacharya approach says that without sthira and sukham, there is no asana. If, in going into a pose, you feel tension or pain, you are not ready for that pose. Accepting one’s self as one is in the present moment and practicing poses patiently and progressively, a sequence of poses is created depending on one’s immediate needs and goals. This allows a variation in practices for seasons, daily routines, energy levels, and whatever else is happening in the person’s life right then. Guided by the breath and attuned to the balanced presence of sthira and sukham, a person can then bring varying degrees of dynamism into his or her practice, perhaps flowing with continual movement in and out of poses, or holding poses longer to explore them more deeply (Desikachar 1995, 25–31).
from „Teaching Yoga” by Mark Stephens