Ardha matsyendrasana should be performed in every asana program if possible, after completing a sequence of forward and back ward bending asanas. In this manner, the back is given the best possible exercise.
Furthermore, the back may be a little stiff after performing a number of backward and forward bending asanas. Ardha matsyendr asana brings about an almost instantaneous release of any tension. This is a good reason why it should be practised after most other asanas.
People who suffer from peptic ulcers, hernia or hyperthyroidism should not do ardha matsyendrasana unless under expert guidance. Women should not practise after two or three months of pregnancy. People who suffer from sciatica or slipped disc may gain much benefit from this asana (many people have already done so in our experience), but you should be careful, especially if your case is severe.
Simpler technique for beginners
Those people who have very stiff backs have a lot of difficulty doing ardha matsyendrasana. Under these circumstances be careful not to use excessive force, or strain yourself, but you should either continue to practise meru vakrasana until your back becomes more flexible1, or attempt the simpler form of ardha matsyendrasana that we will now describe: Sit on the ground with both legs outstretched in front of the body. Place your right leg in the same position as explained for ardha matsyendrasana. Keep the left leg outstretched; don’t bend it. Then repeat the rest of stage 1 and then stage 2 as described for ardha matsyendrasana. All details are basically the same, and even though it is far easier, the benefits are nearly as good. After some time when your back becomes looser, you should try to master ardha mats yendrasana.
Note: If you can nearly do ardha matsyendr asana, but still experience a little difficulty, then to make the asana easier to perform you can make the following adjustments:
1. Place the forward facing foot in front of the ad-joining knee of the other leg.
2. Place the forward facing foot in contact with the inside surface of the forward facing knee, instead of the outside surface.
Again, when your back becomes more supple, revert to the position already described.