The word is derived from the Sanskrit asanam, "a sitting posture." Asanas range from simple, relaxing poses which can be held by people at all levels of ability to complex postures which push the limits of the practitioner's body. Typically, a yoga session involves running through a series of asanasand holding them for varying periods of time. They could potentially be held for long periods of time to focus the mind and body, promoting health, stillness, flow of energy and inward reflection.
In the 2nd Century before Christ, Patanjali wrote down the principles of Yoga practice in the YogaSutras (aphorisms). He named only the meditation posture Asana and the physical postures he termed Yoga Vyayam. However, in common usage the dynamic Yoga exercises also became known as Asanas.
Traditional asanas are only one part of the practice of yoga, which is a religious practice in India. They are designed to stretch and internally massage the entire body, with twisting, bending, and holding accompanied by periods of relaxation. Many people find that integrating a few asanas into their daily stretching routine is quite beneficial; common asanas include back bends, stretches of the legs and arms, and standing poses to promote good posture and balance.
Many asanas were derived from the natural movements and positions of animals and carry the names of animals such as "cat", "deer", "tiger", "hare", etc. These postures make use of examples from nature on how to help oneself. Asanas have a far-reaching effect upon body and mind. The animals instinctively used these movements and positions because of their natural benefits. These effects are attained through the practice of the asanas. For example: Marjari (The Cat) for stretching the body and the spine, Bhujangasana (The Cobra) for the release of aggression and emotions, and Shashankasana (The Hare) for relaxation. The headstand (Shirshasana) and Lotus (Padmasana), are regarded as the supreme or royal Asanas.
Asanas are beneficial for the muscles, joints, cardiovascular system, nervous system and lymphatic system, as well as the mind, psyche and Chakras (energy centres). They are psychosomatic exercises, which strengthen and balance the entire nervous system and harmonise and stabilise the practitioner's state of mind. The effects of these exercises are a sense of contentment, clarity of mind, relaxation and a feeling of inner freedom and peace.