Depending on our purpose, we can analyze parts of the body into many different layers. For a discussion of joint movement, however, two are enough: the two layers of a joint are muscle and bone. Muscle includes muscle and tendon, while bone includes bone and the ligaments. Yogis should train themselves to feel the differences between the muscle and ligament sensations.
The neck is one of the most mobile and accessible of the joints, so we will start our exploration here. When you have learned to discriminate the sensations of muscle and ligament in the neck, it will be easier to feel these differences in the lower spine, as well as in other joints of the body. The following neck stretches are an effective way to start this process.
Drop your chin to your chest and relax. This is a passive, or Yin, stretch for the muscles and ligaments of the back of the neck. The muscles of the neck are on the left and right sides of the centerline. The ligaments we are concerned with are on the centerline. You can learn to feel the difference by comparing the sensations on each side of the neck with the sensations in the center.
Move the head to the right while it is still dropped forward. This movement stretches the muscles on the left side of the neck, making it easier to discriminate them. Moving the head to the left stretches the muscles on the right side of the neck. Bringing the head back to the center should help you distinguish sensations that are neither left nor right, but on the midline. These are the ligaments.
Muscular stretches feel sharper and are easily locatable. Ligament sensations are deeper, duller, and more attached to the bones. This is why Taoists use the expression "stretch your bones" to describe ligament stretches.
This simple exercise should be repeated many times. The distinctions may not be noticeable the first few times, but they become clear with experience. Notice that it is still possible to feel ligament stretches when the head is moved to the left and right. But by exaggerating the stretch on the muscles, it is easier to feel the difference between the two tissues.
Once you have learned to feel the difference between muscle and bone, the next step is to determine how much leverage to use when stretching them. Passively dropping the chin to the chest is a gentle Yin approach. A more aggressive effort would be to contract the muscles of the neck to depress the chin deeper toward the chest. The most aggressive stretch would be to use the hands to gently push on the back of the head. This is the deepest possible stretch for the neck while seated.
All three of the above stretches are Yin. The muscles of the front of the neck are used in the second variation and the muscles of the arms in the third variation. But in each variation, the muscles of the back of the neck are relaxed. This allows the neck to round forward and stretch the joints. However, if you contract the muscles of the back of the neck while doing any of these exercises, you are resisting the forward bend and preventing the stretch. This is a Yang approach. This principle can be demonstrated as follows.
Gently drop the chin and place the hands on the back of the head as before. Now engage the muscles of the back of the neck and try to lift the head up. At the same time gently pull down on the head with the arms. You are now in a tug-of-war with yourself. Your arms are trying to pull the head down, but the neck muscles are trying to lift the head up.
In this experiment, you control both sides of this tug-of-war. You can allow the neck muscles to overpower the arm muscles and slowly raise the head. Or you can allow the arm muscles to overpower the neck muscles and slowly pull the head down.
If you try this experiment, you will discover that as long as the neck muscles are engaged, you will not be able to stretch the back of the neck completely. You should also feel that if you keep your head in a vertical position, your neck is stalemated between the effort to lift up and the effort to pull down. This muscular tension can become very vigorous, but there is no stretch on the joints of the neck.
This is the most important point of these demonstrations: if there is no stretch on the joints, then there is no stretch on the ligaments.
The Lower Spine
We will now extend the principles of analysis we learned from the neck and apply them to the lower spine. It is harder to isolate the movements in this area, but the anatomical principles are the same. The lumbar curve of the lower spine follows the same direction as the cervical curve of the neck.
Sitting in a chair with hands on knees, passively drop forward to stretch the lower spine. As in the neck, the muscles are on the left and right sides of the spine and the ligaments are on the centerline. While bent forward, move the torso to the right to increase the stretch on the muscles on the left side. Moving the torso to the left, you can better stretch the muscles on the right side. Dropping straight forward, you can better isolate the ligaments.
You can increase the stretch of the lower spine by using your stomach muscles to round your spine. You can also do the opposite by using your back muscles to straighten the spine and lift the chest. By alternately rounding and straightening your spine, you can feel how rounding stretches the joints of the back and straightening prevents the joints from stretching.
As with the neck, you can engage in a tug-of-war between your stomach muscles and back muscles. One set of muscles is trying to round the spine, and the other is trying to straighten it.
As with the neck, the muscular tug-of-war between the stomach and back muscles can be vigorous. This can help develop muscular strength and control, but the joints of the lower spine are not stretching. If the joints are not stretching, then the ligaments are not being exercised.
Muscle and Ligament
You can stretch muscles when they are tensed or relaxed. But the only way to stretch a ligament is to hold a posture with the muscles relaxed. When the muscles are relaxed, the ligaments of the joints take the strain. This is essential to maintain the health and elasticity of the joints.
Both layers of tissue need to be kept healthy, so yogis should practice the postures both ways. Yang Yoga is the effort to keep the muscles tensed and engaged. Yin Yoga is the relaxed stressing of the joints.
It is possible to overdue the stretching of muscle or ligaments, but as long as a yogi moves slowly and with little force, the chance of real injury is slight.
Paul Grilley has been studying and teaching yoga since 1979. His special interest in anatomy. He teaches regular workshops on physical and energetic anatomy. Paul lives in Ashland, Oregon with his wife Suzee.