Ardha means half. In the Hatha Yoga Pradipika, Matsyendra is mentioned as one of the founders of Hatha Vidya. It is related that once Lord Siva went to a lonely island and explained to his consort Parvati the mysteries of Yoga. A fish near the shore heard everything with concentration and remained motionless while listening. Siva, realising that the fish had learnt Yoga, sprinkled water upon it, and immediately the fish gained divine form and became Matsyendra (Lord of the Fishes) and thereafter spread the knowledge of Yoga.
After the forward and backward bending of the spine, the Spinal Twist gives a lateral stretch to the vertebrae, back muscles, and hips.
Physical Benefits
Helps to keep the spine elastic by retaining side-to-side mobility.
Helps to relieve muscular problems in the back and hips.
Removes adhesions in the joints caused by rheumatism.
Increases the synovial fluid of the joints, and makes the joints very active.
Tones the roots of the spinal nerves and the sympathetic nervous system, and brings a fresh supply of blood.
Massages the abdominal muscles, relieving digestive problems.
Benefits the gall bladder, spleen, kidneys, liver and bowels.
The prostate and bladder are not enlarged if one practises regularly.
Helps to cure constipation, dyspepsia, stimulates the pancreas and useful for diabetes.
Improves the lung capacity.
Mental Benefits
Helps to cure disorders of the nervous system.
Brings peace of mind.
Pranic Benefits
Augments the Prana Sakti (vigour and vitality), removing innumerable diseases.
Rouses the Kundalini (potential spiritual energy).
Limitations
People who have recently undergone abdominal surgery may avoid.
Common Faults
Buttocks are lifting off the ground.
Back is not straight, and the body is leaning, rather than twisting laterally. If the body leans, rather than twisting, you will not gain the benefit of the asana.
Looking over the wrong shoulder.
Hand is allowed to hang freely, rather than clasping the opposite ankle.
Foot is not flat on the ground.
Back hand is too far from the body.
Note: Please perform the yoga under the guide of a certified yoga teacher especially for beginner. You are at your own risk and responsible if you perform on your own. Whatever provided here is just act as an information.
Source from Yoga Mind & Body - Sivananda Yoga Vedanta Centre