Yogasana ( popularly known as Yoga in the West ) is a timeless treasure of India and a great gift of ancient India to mankind for a healthy body, healthy mind and an enlightened soul, crossing all man-made artificial boundaries.
Ordinary physical exercises develop the superficial muscles of the body only. One can become a Sandow with a beautiful physique. But Yogasanas are intended for the thorough exercise of the internal organs, viz., liver, spleen, pancreas, intestines, heart, lungs, brain and the important ductless glands of the body, which are called endocrine glands, viz., thyroid and parathyroid at the root of the neck, adrenals in spleen, pituitary and pineal glands in brain, which play a very important part in the economy of nature, in maintaining health in metabolism and in structure, growth and nutrition of different kinds of cells and tissues of the body.
India today is in need of a strong and healthy race of men & women. Various factors have brought about their terrible degeneration. Regular and judicious practice of these valuable exercises prescribed by our Rishis ( Ancient Indian Sages ) of yore, will doubtless pave a long way in regenerating the race, and in the production of such a strong and healthy race.
In olden days, these Yogasanas were practised in Gurukulas, and so the people were strong and healthy and had long life. In schools and colleges today, these Asanas should be introduced.
The postures are as many in numbers as there are numbers of species of living creatures in this Universe (84 lacs of bodies). There are 84 lacs of Asanas described by Lord Shiva, the great Yogee & the Hindu God of destruction. Among them 84 are the best and among these 84, 32 have been found very useful for mankind.
There are some Asanas, which can be practised while standing. They are Tadasana, Trikonasana, Garudasana, etc. There are some which can be practised sitting. They are Paschimottanasana, Janusirshasana, Padmasana, Lolasana, etc. Some are practised while lying down. These are Utthanapadasana, Pavanamuktasana. Weak and delicate persons can do Asanas while lying down. Some Asanas such as Sirshasana, Vrikshasana, Sarvangasana, Viparita Karani Mudra, etc., are done with head downwards and legs upwards.
Yogasanas should be practised in a well-ventilated, clean room where there is free movement of fresh air. The floor must be even. Asanas can be practiced on the sandy bed of rivers, open airy places, and by the sea-side also. If you practice them in a room, see that the room is not congested so as to allow free movement of hands, legs and of the body.
Asanas should be done on empty stomach in the morning, or at least three hours after food. Morning time is best for doing Asanas."
Here are some images from the wold wide web of these life giving, invigorating, rejuvenating Yogasanas :