Ashtanga Yoga means eight step or eight “limb” yoga. These are described in Patanjali’s Yoga Sutras.
The eight steps are divided into two parts – the first four are called external limbs, they are: Yama (suggestions for social behaviour: non-aggression, truthfulness, non-theft, appropriate sexual behaviour and non-greed), Niyama (suggestions for personal disciplines: self purification, contentment, self-discipline, self-study and surrender to the ideal of yoga), Asana (physical postures) and Pranayama (breathing exercises).
The four “internal” limbs are Pratyahara (sense withdrawal), Dharana (single pointed concentration), Dhyana (meditation) and Samadhi (the state of yoga in which the ultimate truth is experienced). Once the four “external” limbs have been mastered, the internal limbs start to unfold naturally.
The first two parts of Ashtanga Yoga (Yama and Niyama) are very difficult. Complete non-violence which is the first of the Yamas is in fact almost impossible. Truthfulness in conjunction with non-violence is also very difficult. Therefore the practice of asana (physical postures) is suggested first. The asanas help to strengthen the body and clarify the mind so that moral development is easier.
“They (yama and niyama) are very difficult. If you have a weak mind and a weak body, you have weak principles. The yamas have five limbs: ahimsa (non-violence), satya (truthfulness), asteya (non-stealing), brahmacharya (continence), and aparigraha (non-possessiveness). Ahimsa is impossible; also telling the truth is very difficult. The scriptures say speak that truth which is sweet; don’t speak the truth which hurts. But don’t lie, no matter how sweet it sounds. Very difficult….That’s why you build a good foundation with asana and pranayama, so the body and mind and nervous system are all working; then you work on ahimsa, satya and the other yamas and niyamas.”*
So the physical postures create a stable foundation for pursuing the other aspects of yoga. They return the practitioner to good health and eliminate the distractions caused by disease and an unstable mind.
As one begins to practice yoga, one sees that the eight steps are not, in fact separated or sequential, but are integrated. With the practice of physical postures one becomes mindful of the necessity of the yamas and niyamas, one begins to control the vital energy, the senses turn inward, concentration improves, states of meditation and bliss spontaneously occur.