The following article was submitted by yoga teacher Frances Marshall

Vital energy flowing through thousands of minute pathways or meridians nourishes and enlivens every cell of the body from the soft surface of the skin to the bony skeletal framework deep within the multiple layers of muscles and connective tissue. Connective tissue, fascia, is everywhere in the body, wrapping around the organs, glands, muscles and ligaments in thin energy-charged layers. Yin Yoga works directly with these tissues, stressing and stimulating the stiff and inelastic ligaments and tendons and, as a consequence, the energy pathways which consist of visible tracts of hyaluronic acid crystals.

Yin Yoga classes are designed to target particular meridians. One class will target the kidney meridian, another the liver. The kidneys are of primary importance for a yoga practice aimed at strengthening the bones as they control the growth and development of bones and nourish the marrow, the body's source of red and white blood cells. According to Traditional Chinese Medicine, weak kidney energy is a primary cause of low bone mass or osteoporosis. The kidneys also regulate the body's acid-alkaline balance (pH); an over-acidic pH balance (below 6.5) leaches calcium from the bones.

In Yin Yoga posture shapes are adapted to individual conditions, needs and intentions as long as the primary focus of the pose is maintained, i.e. targeted connective tissues and major energy pathways are stressed. It is recommended that we moderately, and regularly, stress and balance these tissues to maintain and enhance the body's vital energy.