The practice of āsana can be yoga sadhana, spiritual yoga practice, as we work to reduce the power of klesas, afflictions (as mentioned in the previous posts, here and here) or even transcend them. Cultivation of discrimination helps us transcend our limitations in the practice of asana. For example, on the physical level--annamaya kośa (musculoskeletal sheath or layer of being, previously explained in this post)-- realizing the temporality of the experience of physical discomfort (such as sweating and working very hard to hold a posture or action in a posture), and intellectually realizing that what is painful in the present may bring health or awareness as a result, and that the seeking of only pleasurable experiences leads to disease and dullness.
When the kleśas are emotional, such as dvesa (aversion) they manifest themselves in the form of strong dislikes: hating a particular pose or category of pose, hating working hard and sweating or disliking being still and practicing restoratives from time to time. On the other hand, the affliction, rāga, has to do with our preferences and attachments, which we can find in practice also: for example, loving backbends, or restoratives, and only wanting to practice these postures. These kleśas of aversion and rāga are very personal as they arise from our individuality (ahamkāra) . Our intellect may come up with very well reasoned explanations for the avoidance of our dislikes, such as these poses are too hard for me because I am too old, too stiff, wrong body type. It is the duty of the yoga practitioner to discriminate and cultivate non-attachment and non-identification with fluctuations arising from our individuality (asmitā). Then our practice elevates to the spiritual. So in the realm of our dislikes, we must work to cultivate the opposite. This is how we develop tolerance and equanimity even when faced with our likes and dislikes.
When faced with kleśas on the instinctual level, abhiniveśa, fear of dying or clinging to life, can also arise in the practice of āsana when we are faced with changing who we are in the present, for some unknown future self. In āsana class and practice we may be faced with our deeply ingrained habits and the work we need to do to change in order to cultivate health and balance. Fear also arises at times when we move into a new space in our practice, around an injury or memory of an old injury, or while working on something very difficult. As spellbinding as they are, these kleśas are to be recognized, and reduced through the practice of yoga sādhana, by using the methods recommended by Patañjali, author of the Yoga Sutras, for the control and prevention of afflictions.