There are three things that we physically do to our bodies in yoga asana practice: we compress tissues, we stretch tissues, and we twist tissues. Technically these three movements are called compression, tension, and shear. The drawings show each of these movements. For example, in back bends we compress the facets of the vertebrae into each other (which, as we will see, is very healthy for the bones); in forward bends we stretch the fascia, muscles, and ligaments along the back of the spine; and in twists we provide a shearing force between the vertebrae and the ribs, which both compresses and stretches the tissues between each pair of ribs.
Yoga promotes the flow of energy in the body through both stimulating energy release (especially in the active yang practices) and through removing deep blockages to the energy flow (especially in the more passive yin practices). Our blood and lymphatic systems serve the same function as the warm water in the example of cleaning a sponge. Another analogy is a garden hose that has been left unused for years, lying in the grass of an overgrown back yard. Insects and mud (toxins) eventually clog the hose (which could be called a “meridian” or “nadi“). When the water (which could be called our energy or “prana“) is turned on, it can’t flow. These clogs have to be removed, and we do so by turning on the water and bending and stretching the hose. Once the flow of energy has been freed or increased, information and nourishment flow throughout the body. Chapter Five: The Energy Body, describes this in more detail.
Our physical bodies are made up of many types of tissues and these tissues respond differently to exercise. Yang yoga is excellent at working the muscle tissues. Yin Yoga is especially effective at working the deeper connective tissues of the body. To fully understand the benefits of yoga, we need to understand the nature of these tissues. The next several sections take us further along our journey of exploration by investigating the:
(Next: Tissues and Their Flexibility )