The practice of asana is one aspect of yoga that we will look into in detail.

There are various methods of practicing the asanas or yogic positions. Some consider it as a type of exercise and some feel that sweating is important during the practice. These practices are known as power yoga or hot yoga. While practicing the positions we should know the importance of the practice and the effects on the body.

The effects of yoga practiced in the traditional way are different from the way it is often practiced in the west. Let us see some of the effects of yoga practice at the anatomical level on the body.

1. Moving in and out of the positions

While practicing the positions honouring the suggestions of your body is very important. The position is to be adjusted if you feel a painful stretch. The pain will cause a state of anxiety and may lead to an injury at the physical level. Awareness of the body is very important in the practice, the destination of the practice of yoga is relaxation and it can never be achieved by jerking and pushing into positions. Smooth and graceful movements are expected in the practice of yoga.

2. Agonist and antagonistic muscles

Co ordination and co operation of these muscles is very important. The agonist muscles are the primary movers of the joints and the synergistic muscles help them.  The antagonistic muscles monitor and help in making the movements smooth and with control. This helps to maintain and hold the joint surface in position. Alignment of the joint is dependent on these antagonistic muscles. If the movement is smooth and slow the alignment of the joints can be maintained and the injuries are prevented.

3. Concentric shortening and eccentric lengthening

When the muscles contract all the muscle fibers will contract at the same time and this is known as concentric shortening of the muscle which is necessary to carry out any action. On the other hand when the muscle relaxes all the muscle fiber will not relax at the same time, some fiber relaxes and the others remain contracted. Some muscle fibers will resist the process of relaxation. This is useful to prevent the fast relaxation of the muscle thus preventing the jerks during relaxation and preventing injury. This is called the eccentric lengthening of the muscle which is important during the release of any yogic asana.

4. Myotatic stretch reflex

It is a reflex found through the body. The stimulus for this reflex is any dynamic shock. The receptors are present in the muscle spindle, they are stimulated and the impulse is carried through the motor neurons.  When the neurons are stimulated repeatedly the effect is shortening of the muscle fiber. It reduces the flexibility but helps in increasing the strength of the muscle. This effect is essential for dynamic sports and in athletes where the movements are fast and with jerks. In the practice of yoga this reflex is to be minimized as the objective is flexibility. The movements should be slow and there should be no dynamic movements as the flexibility will be reduced. Fast movements, jumping in and out of the positions and jerks are not expected in the practice of yoga as the reflex will be stimulated and the muscle will be shortened and the flexibility will be less. Also the possibility of injury increases because of the shortening of the muscle fiber. 

5. Clasp knife reflex

It is a stretch reflex. It works like the closure of a pocket knife. When the knife is closed there is an initial resistance and then the resistance is lost and the knife will close with a snap. The same thing happens in the muscles, there is initial resistance and there is relaxation of the muscle fiber. It causes the muscle to relax and increase the flexibility. The stimulus for this reflex is a contractile tension or a pull on the muscle tendon. The receptors are located at specific points at the junction of the muscle and the tendon. It stimulates the motor neurons and prevents the contraction of the muscle, inhibits the activity and helps in relaxation.  In the practice of yoga this reflex is stimulated if we maintain the position for some time. Maintenance of position will act as a stretch on the muscle and stimulate the reflex. The effect is relaxation and flexibility of the muscle. The reflex can also be stimulated manually by deep pressure at the specific points. It is used during the process of massage or even in sport therapy to reduce the stiffness of the muscle. 

Considering this it is very clear that the objective of the practice of yoga is relaxation. So the movements should be slow and the position needs to be maintained for some time. If this is not followed then there will be no difference in the practice of yoga and any other exercise and the effect will be the same.  

- Dr.Prafulla Dorle