handsThe purpose of some Yoga postures is to stress the joints in a beneficial manner. This article explores the different forms of stress that can be placed on a joint so that a Yogi can make the appropriate choices when practicing.

Some yoga postures are designed to beneficially stress the joints of the body to stimulate their strength and flexibility. There are two fundamentally different types of stress: tension and compression. Yogis should learn the difference between the two.

Tension is the familiar sensation of tissues being stretched. Compression is the sensation of tissues being pressed or pushed together. Both of these stresses are beneficial if done in moderation.

When a Yogi is stretching a joint he is stretching ligament or tendon or both. When a Yogi is compressing a joint he is compressing bones. We can make these distinctions clearer with some simple hand exercises. The lessons we learn with our hands apply to all the other joints of our body.

The muscles most responsible for clenching the fist or for extending the fingers are in the forearm. If you palpate (touch) and squeeze the muscles of the forearm starting near the elbow and working towards the wrist you should notice that the muscles are soft and malleable nearer the elbow but become smaller, harder and more string like nearer the wrist. These string-like structures are tendons.

They are extensions of the forearm muscles that connect the muscles with the joints of the fingers. The tendons on the back of the hand extend and spread the fingers to open the palm. The tendons on the palm side of the close the fingers into a clenched fist. Muscles shorten and become hard when contracted. They lengthen and become soft when relaxed. The tendons feel tough and fibrous whether the muscles are tensed or relaxed.

Palpate the muscles of your forearm near the elbow while alternately extending your fingers and clenching your fist. You should be able to feel the muscles tense and relax. But if you palpate your wrist while extending and clenching your hand it should feel very different. The tendons near your wrist don’t tense and relax the way muscles do, they are just pulled and released by the muscles of the forearm.

When muscles are contracted the tendons pull on the bones and the joints are compressed together. This limits their range of motion but makes the joints more stable. Some simple examples should make this clear.

First use your left hand to wiggle and bend the fingers of your right hand while it is relaxed. The joints of your right hand fingers are easy to bend and straighten. Take hold of the middle finger of your right hand and gently pull on it. You should be able to feel the joint of the first knuckle near your palm gently stretching as you pull and release your middle finger. This is only possible because your muscles are relaxed. Now extend the fingers of your right hand as hard as you can and stretch the palm open. If you maintain this tension it is very difficult to pull and stretch the knuckle of the middle finger as before. This is because the tendons are pulling on the bones and compressing them together. This makes the joint more stable but less mobile.

This is a very important point: Muscular tension compresses the joints and thereby limits their range of motion. Sometimes this is desirable, sometimes it isn’t. If it is your desire to prevent a joint from going to its full range of motion it’s a good thing. But if you are attempting to stretch the joint to its full range of motion it’s a bad thing. Try this exercise and remember that we apply these same principles to the other joints of the body as well.

Extend the fingers of your right hand. Try to extend them so that your first knuckles are extended or “bent” back toward the back of your wrist. For many people this movement is not very big.

Now keep the fingers extended and also use your left hand to push them back further. Using the leverage of the left hand you can bend the knuckles farther back. But to bend the fingers back as far as possible we need to relax the muscles of the right hand completely. With the right hand relaxed use your left hand to push the fingers back as far as possible. This is usually a much greater range of motion than when the muscles are tensed.

Muscular passivity not only allows the greatest range of motion it is also the least compressive to the joint tissues. This is why a chiropractor or osteopath often prefers to have the muscles surrounding a joint to be relaxed before attempting a therapeutic manipulation.

We can use this simple experience to compare the benefits of yin yoga, yang yoga and regular yang exercises like weight training. In our simple experiment we would classify the attempt to bend the fingers back using only muscle as regular yang exercise. Using the leverage of the left hand while the muscles are tense is a yang form of yoga. Using the leverage of the left hand while the muscles are relaxed is a yin form of yoga.

Yang exercise is always accompanied by compression of the joints. Compression is good for joints and stimulates the bones to healthy growth. This is one reason why vigorous yang exercise is prescribed to prevent osteoporosis. But yang exercise doesn’t allow the full range of motion. Yang exercise develops strong muscles and bones but can leave the joints contracted and stiff. This is common among athletes. Bending the fingers using leverage and muscle tension is a yang form of yoga. It develops strength and increases the range of motion. This is why yang yoga leaves a practitioner feeling more stretched and relaxed than yang exercises like weight training. But yang yoga doesn’t exercise the full range of motion.

Bending the fingers using leverage while the muscles are relaxed is a yin form of yoga. Yin yoga safely, even pleasantly develops the full range of motion of a joint. This type of practice leaves the practitioner feeling relaxed, light and free. Yin yoga by itself won’t develop the strength and stability a joint needs. Yang yoga by itself will not exercise the full range of motion. This is why different forms of yoga can and should be practiced to supplement each other.