As we pointed out earlier, the job of our muscles is to protect the joints. The muscles do this by tightly closing the joint. There is an easy way to see this, which we described at the beginning of our journey. Take your right forefinger in your left hand. Relax the right hand and finger and apply a gentle pull with your left hand. Observe the base of the right finger you may notice a slight dimpling or extension across the knuckle. Even if you can’t see any movement, you will definitely feel an opening there. Now contract the muscles of the right finger tightly and try to pull the finger. Notice the difference? There is no movement at all. The muscles have actively bound the joint so that no movement is possible.
The reason so much time and care is given to aligning the body and engaging our muscles properly in our active, yang-styles of yoga is to make sure the joints are not damaged by our yang movements. This is wise. As the above demonstration showed, the muscles act to protect the joint and do not allow the joint to open.
As we will soon see, however, a chronically closed area of the body, whether it is in our muscles, our fascia, or in our joints, becomes permanently closed. If we only close our joints and never allow them to resume their full range of movement, we will lose the original range of motion. Yang yoga is not designed to open the joints. Yin Yoga is. In fact, Yin Yoga has four major benefits for our joints. We will examine these next.