By Linda Oshins
As you may know, I’m a voracious reader. I also go through stages when I question what I know. How do I know something is true? Even if I’ve read research studies on a particular question, is a population of yogis enough like the study population for the study to apply? What are my unexamined assumptions and my blind spots?
For my next several blog entries I thought I would take you with me on a couple of those fact-finding missions, recommending a book along the way. For this blog spot, the topic is physical balance. Where am I in space and how do I know where I am? My thinking about balance had been: As we age, many of us lose our sense of balance. Yogis practice balance poses. Ergo, yoga is good for you. But when you lose your sense of balance, what are you losing exactly? What can practicing balancing poses do to help and how? The book Balance: In Search of the Lost Sense by Scott McCredie answered those questions and others.
Aspects of the Sense of Balance
The classic five senses—sight, touch, taste, smell, and hearing—are associated primarily with one sense organ (sight with the eyes, hearing with the ears and so forth). Unlike those senses, the sense of balance depends on three sensory inputs: proprioception, the vestibular system, and vision. McCredie offers the opinion of some researchers that spacial orientation is so important to survival that, with three interwoven sensors, the sense of balance has fail-safe and back-up systems. Whenever any of the body’s three sensory inputs for balance become dysfunctional, the brain can lean to adapt by relying more on the remaining intact senses.
Proprioception is the system by which the body senses its own motion. It can be thought of as a variation on the sense of touch. It is unconscious in the sense that you can close your eyes, wave your arm in front of your face and know where it is in space without thinking about it. It is made up of stretch receptors located in muscles and joint-supporting ligaments and proprioceptive nerves that detect the movement of muscles and joints and the strength of effort being employed in movement. “Proprioception tells the brain how muscles are moving and where body parts are located in space, but it provides only information about relative positions—for instance, where your arm is in relation to your shoulder, or your leg in relation to your torso. It doesn’t provide clues about the absolute position of your body in space, which is necessary for any kind of complicated motion. For that, the brain relies on the vestibular system, which serves as a sort of inertial-gravitational guidance mechanism.” (p. 97)
The Vestibular System
The vestibular system has several parts—the semicircular canals of the inner ear and the utricle and the saccule, two saclike structures located beneath the semicircular canals. The head of the vestibular system is formed by the semicircular canals. When your head rotates, fluid moves in the canals, exciting minute hair cells. Those cells send signals to the brain that tell it in what direction, how fast, and how far the head is moving. The utricle and the saccule house hundred of tiny particles of calcium carbonate, which are like little rocks. When you move your head, the crystals move too, bending underlying hair cells. That tells the brain how your head is moving and its position relative to gravity.
Vision tells you how the body is oriented to things like trees or doorways, which are vertical, and gives you information about your environment (tilt and texture of the ground for example).
Yoga and Balance
So what does this mean to me when I do my yoga practice or teach a yoga class?
I’ve had beginning students who, when standing with their eyes closed, can’t tell whether their feet are toed-in or toed-out (legs internally or externally rotated at the hip for your yoga teachers), who cannot feel the curvature of the low back when bending forward, or who don’t know how to keep their center of gravity suspended over their feet when moving through sun salutes. On a whim, I once asked a roomful of seated students to close their eyes and place their hands on their center of gravity, which is located in the pelvis below the navel. To my complete surprise, most students touched their forehead! Their whole body was below that hand but the center of the world was the thinking mind! What about the wealth of sensation and wisdom available through the body, its relationship to the earth, to gravitational pull, to itself?
I’ve always especially valued what I think of as the sensory tone poem of yoga. That luscious feeling of moving. With practice feeling inside, I’ve had ever more subtle conversations with my body, feeling into places and sensations I remember from childhood, bringing aspects of the body alive and into my conscious awareness, leaving behind the repetitive movements that are part of my work day, like typing on the computer, for the full range of movement and feeling open to me. Physical awareness is one of the great gifts of yoga and easily accessible to every yoga practitioner at every level of practice.
I like to heighten my physical sense of body movement by closing my eyes during practice, making the brain rely more on the proprioceptive system to tell me where I am. With closed eyes, focused on sensation, I’m not lost in the future or the past. I am not more or less than what I feel to be true.
Our organs of balance do decline with age. “Most authorities believe our ability to maintain equilibrium peaks in our twenties and then slowly begins to deteriorate until we reach our sixties, when it plummets…. How rapidly the sense of balance diminishes depends on our genes, on the natural process of aging, and also to a large extent on how physically active we are and the types of activity we do…. Proprioceptors on the bottoms of the feet lose sensitivity, causing a lag in communication with the brain about the foot’s position on the earth. And the tiny hairs within the vestibular system’s semicircular canals and otoliths (the “rocks” in the inner ears) also lose sensitivity, decreasing the speed at which the gravity and motion sensors relay information to the brain. There is also a link between muscle strength, especially of the legs, hips, and trunk, and balance.” (p. 190) But balancing practice helps. “One-legged stances are a proven means to improve balance. Three variations were used in a study at Indiana University in 2005, designed to see whether a simple, inexpensive, home-based program could bring about positive results. A group of healthy fifty-five- to sixty-year-olds practiced the postures fifteen minutes a day, four days a week, for six weeks. At the end of the study, the researchers found that the subjects’ “sway patterns”—the subtle, almost undetectable movements the body makes, front to back and side to side, as it reacts and adjusts to the destabilizing effect of gravity—had improved (made the body more stable) by 16 percent.”
“… Older people who exercise regularly or participate in sports, one study showed, have a smaller sway pattern, and thus better balance, than those who aren’t active. …there is almost no difference in the sway patterns of elders who have exercised all their lives and those who began after retirement, indicating that it’s never too late to start a strength- and balance training program.” (p. 210)
So whether you are practicing yoga for the pure pleasure of the sensation of movement or to keep yourself strong and balanced throughout life, do practice!
Taken from Balance: In Search of the Lost Sense, by Scott McCredie.