Ekapada Shirashasana :
Cutting the Ego in asana practice
Some poses in yoga have a symbolism. For example Vasishtasana and Kapotsasana (shown to the left), two poses that require a lot of effort and result in an upsurge of energy through the body, symbolize the powers of sages Vasishta and Kapota respectively. Similarly the leg behind the neck poses in yoga are a symbolism for how the ego can destroy us if we are not careful. The leg that goes behind the head symbolizes a sword as shown in the illustration below. The sword (behind the neck) is a constant reminder that if we are not watchful, the ego will destroy us.
2) The Yoga Sutras on Ego
Sutra 2.17 states that the cause of the avoidable suffering in life is the ego i.e. the identification that the body and the atma are the same. In other words, when one thinks, out of ego, that one is a great yogi because he or she can do advanced poses, then it causes suffering down the line (either from injury or from mistreatment of others).
3) Ego in students (and teachers)
Famously or infamously, some teachers in the trademarked ashtanga yoga practice, are supposed to hold their students at an asana for years at a time until the students gain perfection, before they can move on to the next asana in the sequence. Such strict teachers say that such discipline not only prevents injury in the student but also curtails the student's ego because the student wanting to do poses of increasing complexity quickly, is driven by ego.
On the other hand, what such strict teachers forget is that their detaining the student and not letting him/her progress through the sequence is because of their own ego and not due to the student's. Such high handed behavior that is seen in some Ashtanga yoga teachers not only creates a sense of stagnation in the student but also is bad for the psyche of the student. Pattabhi Jois' son, Manju Jois, the well liked and a renowned asana teacher, famously said :
One, supposedly senior, Ashtanga Yoga teacher prided himself on the fact that he "came down heavily on students who exhibited ego and had zero tolerance for them". While I got along fine with him, his lack of awareness of his own excessive ego and wanting to be the dominant person in a room, created such a negative energy, that I as well as others stopped practicing with him, altogether.
The entire purpose of Yoga is to cut asunder the ego that identifies the indweller (Purusha) with the body (Prakriti). Unfortunately, many advanced asana practices have become body-centric and cater to the ego and thus are in opposition to the original purpose of doing asanas. A constant reminder of the symbolism behind the asanas will bring the practitioner as well as the teacher to the original intent of this practice.