In the ancient writings on yoga there are major two commentators who give advice on the practice of asana.
Patanjali composed the Yoga Sutra over 2000 years ago, he gives Asana as one of eight branches of Yoga let us consider his definition and description first:
“Sthira Sukham Asanam”, Sadhana Pada Sutra 46
Patanjali says, Asana should be steady and easy. In Sutra 47 and 48 he says to master asana restlessness should be reduced and one should feel timelessness while maintaining the pose. Then the mind becomes free from the dualities of the body.
If one has ever tried to sit still for a long time then you know that after a while pain creeps into the body. Thinking that a little movement will alleviate the pain we begin to fidget. Soon the discomfort of the body has disturbed the mind and the mind reacts by moving the body around. Asana and concentration have been lost. The perfect Asana requires presence of mind, one is aware of the sensations in the body without automatically reacting by moving.
The magic of asana is that with practice the body will become transformed by conditioning the mind. Asana shows us the tensions held in the body. The experience is a mental one and the holding pattern of muscle tension is revealed as an action of the mind. This tension held in the body has its root in the mind. If we remain still while maintaining a pose we are releasing tension from both body and mind. The unconscious program in the mind which organises the posture of the body is altered if we can find a new comfortable balance. Over time the body finds a more appropriate symmetry. Over time left and right, upper and lower, inner and outer become balanced.
In sutra 49 patanjali says that once asana is firm and steady then it is appropriate to begin the practice of pranayama. Patanjali is the classical authority on yoga, it is interesting to note that these four sutra contain the whole of his teaching yet he mentions not one individual posture. Patanjali speaks of the essence of asana and gives the reason for its practice. Within Indian yoga traditions it is said that the mastery of asana is to be able to sit still comfortably for four hours.
The other ancient authority we look to is Swatmarama who composed the Hatha Yoga Pradipika over 1000 years ago. This classical text describes Asana in detail and gives instruction on some 15 different poses. The Pradipika gives a graphic explanation of the relationship between mind and body and the interplay of subtle energy known as prana. In the Pradipika Asana is used to purify the Nadis, meaning the network of channels for Prana. This is an important preparation for harnessing the dormant potential or Kundalini which comes with other practices of pranayama and dhyana (meditation).
Everyone can relate to the idea of nervous energy, imagine a fidgety child who cannot sit still, or an adult who has taken too much coffee. Hatha Yoga is a process which allows for an efficient use of energy in the body. Asana is a system of physical exercises that has at its heart the integration of mind and body. The nervous system which coordinates the use of the bodies muscles is being conditioned to function effectively. Exercise physiologists now know that the peripheral nervous system can be conditioned to supply better electrical impulses to muscles through exercise. If you are interested in these health aspects of practice I suggest reading the page on Yoga Therapy.
In modern times the practice of Asana has blossomed into a rich and diverse culture with many different styles and methods and thousands of different postures from basic to advanced. As in most fields of endeavour a teacher is required to explain the safe and effective way to practice. More important is to understand the essence of the practice. Having proper instruction is vital and then of course the individual has to work to make the experience real.