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The physics of balance May 26, 2011

Filed under: Asanas — rainbowyoga @ 12:11 am


The three essential elements of balance are alignment, strength, and attention. Alignment of the body with gravity is crucial; it makes balance physically possible. Strength gives us the power to create, hold, and adjust alignment. And attention continually monitors alignment so we know how to correct it from one moment to the next.

In many ways, balancing the body on one leg is much like balancing a seesaw. The same laws of physics apply: If you align the center of gravity over the base of support, you balance. If you don’t, you don’t. It’s as simple as that. Of course, since your body is quite a bit more complicated than a seesaw, balance is often not so simple to achieve.

Let’s explore Vrksasana to see how alignment with gravity works in a one-legged balance. When you stand in Tadasana (Mountain Pose) preparing for Vrksasana, your feet form your base of support. The center of gravity—the point you need to place exactly above the center of your base in order to balance—varies a little from person to person. But it’s generally a little below the navel, deep inside the belly; and, since humans are more or less symmetrical right to left, it’s right on the midline. If you stand in front of a mirror and imagine a plumb line that runs from the ceiling to the floor and passes through this center point, you can see that it ends right between your feet, at the center of your base of support. Your weight is evenly distributed on either side your midline. It’s pretty easy to balance here.

But the moment you lift your right foot off the floor and start to draw your right knee out to the side for Vrksasana, everything changes. Your base of support becomes narrower; now it’s just your left foot. And the weight of your leg swinging out to the right moves your center of gravity to the right, so it’s no longer on your midline. To compensate, you automatically shift your whole body to the left, working to bring your center of gravity back onto the new plumb line that runs through your new base of support.

To do this, you must distribute your body weight in equilibrium on either side of the plumb line. But it’s important to understand that distributing your weight in equilibrium doesn’t necessarily mean placing equal weight on each side of the line, as you do in Tadasana. To illustrate how distribution of weight works, think of two people of unequal weight trying to balance a seesaw. They can balance if the lighter one sits farther out and the heavier one sits closer to the center.

In yoga, the same principles apply: A light part of the body far away from the center of gravity can counterbalance a much heavier one that’s closer to that center. In Vrksasana, for instance, as your relatively light bent leg moves out to the right, quite a ways from your center, you counterbalance by moving heavier body parts—your hips and torso—slightly to your left. Just like two people striving to maintain balance on a seesaw, you must pair any movement you make on one side of the plumb line with an opposing movement on the other side.

Every time you use your arms to balance by holding them out to the sides like a tightrope walker, you’re intuitively taking advantage of the fact that as weight moves away from your center of gravity, it has a greater effect on your equilibrium. If you have difficulty in Vrksasana and otherone-legged balances, by all means use your arms to help stabilize yourself.

It’s obvious that moving your center of gravity horizontally affects your balance, but moving it up and down can have an equally dramatic effect on your pose. You’ve probably noticed that Vrksasana becomes a little more difficult to balance in when you bring your hands from your sides to prayer position at your heart, and even harder when you take your arms overhead. That’s because each of these movements raises your center of gravity. When the center of gravity is high, just a few degrees of tilt can move it far enough off the plumb line to upset your balance; when it is low, there’s more room for error. If you have trouble balancing in Vrksasana, try lowering your center of gravity by practicing the pose with your standing-leg knee slightly bent and the arms in a lower position. Only straighten the knee and raise the arms overhead after you have achieved success with the knee bent. Starting with the knee of the standing leg bent can also be very helpful in the other one-legged balances.

You can also enhance your equilibrium in these poses by spreading the toes and the ball of the standing foot. The broader your base, the more stable you are, and even the slightest widening of the sole of the foot is surprisingly helpful.

Although one-legged balances all have much in common, each also presents specific challenges. In Vrksasana, for instance, you are especially likely to fall toward the inner edge of your standing foot. When you’re first learning the pose, one way to counterbalance this tendency is to shift the hips a little more in the opposite direction, bringing more weight onto the outer edgeof the foot. This movement can keep you balanced long enough to build strength, endurance, and, eventually, more vertical alignment.

Another way is to use the strength of your foot and lower leg muscles to shift your center of gravity. Actively pressing down into the big-toe ball of the foot and the inner heel causes a rebound up through your body and shifts your center of gravity toward the outer edge of your foot; pressing into the outer edge of the foot shifts your center of gravity more over the inner edge. Such skillful use of your muscles is an important part of balancing. While alignment with gravity is crucial, your bones can’t put themselves into line; they need the muscles to move them into position, hold them there, and reposition them as needed. This is where strength comes into the picture.


The gluteus medius connects the outer rim of the pelvis to the upper thighbone, and it’s easy to find. (The gluteus minimus lies underneath the medius, so it’s harder to palpate.) You can feel yourleft gluteus medius by first running your left fingertips along your pelvic rim until they’re exactly at the side of your body, then sliding them down about two inches and pressing them into the flesh.

If you continue pushing on this spot as you lift your right foot, you will feel the gluteus medius harden beneath your fingertips. It will contract the instant the foot leaves the floor, and it may get even firmer as you progress into Utthita Hasta Padangusthasana, especially if you do the variation with the lifted leg off to the side. The gluteus medius and gluteus minimus of the standing leg must work very strongly in this variation, because lifting your other leg so far out to the side gives its weight tremendous leverage to pull that whole side of the trunk down. The gluteus medius and minimus of the lifted leg are also very active in this pose. That’s true for some of the other one-legged balances too, including Ardha Chandrasana and Virabhadrasana III (Warrior Pose III).

The best way to strengthen these crucial muscles is—you guessed it— to practice lots and lots of one-legged standing poses! All the poses discussed in this article will help; each will work the muscles in a somewhat different way. To maximize the value of a pose for strength training, try practicing it with the support of a wall or ledge so you can hold it for a long time without losing your balance. Hold it until muscle fatigue causes you to lose proper positioning of your limbs or trunk. Then come down and practice on the other side. You’ll get even better results if you repeat this process several times.

Smaller muscles are also important in helping you balance in poses like Vrksasana and Utthita Hasta Padangusthasana. When you stand in them, you’ll probably find your foot and ankle making frequent side-to-side adjustments. The inner foot presses down (pronation), then the outer foot (supination), then the inner foot again, and so on. If you pay attention to this involuntary small dance, you’ll see that pressing down the outer edge of the foot shifts the body’s center of gravity toward the inner foot, and vice versa.

Being narrow, the foot has very poor leverage for shifting the entire mass of the body left and right. The muscles that press the inner and outer foot down must, therefore, be quite strong to move the center of gravity far enough—and fast enough—to maintain balance. The primary muscles involved are the tibialis anterior (on the outer front shin) for supination, and the peroneus longus and brevis (on the outer calf) for pronation. The supinators are strengthened by almost every standing pose, one-legged and two-legged alike. The pronators are strengthened more by one-legged standing poses, especially Vrksasana, in which they help offset the tendency to overbalance toward the inner foot.

When you stand on one foot, one leg must do the work of two. To appreciate how important strength is in balancing, let’s take a close look at the muscles used in Utthita Hasta Padangusthasana (Extended Hand-to-Big-Toe Pose).

As you stand in Tadasana in preparation for the pose, each hip is supported by the leg below it. The instant you lift one foot off the floor, the foundation of the hip on that side is pulled out from under it. Yet you usually don’t collapse toward the ground. What holds you up? Two muscles in the opposite-side buttock, the gluteus medius and the gluteus minimus, do most of the work. These are the two most important muscles to strengthen to improve all of your one-legged balancing poses.

The better you get at balances, the less muscular effort you need to maintain them. This is because you become more skilled at using your bone structure to support your weight, rather than wasting muscle energy to do so. You also waver less, so you need to make fewer and smaller muscular corrections. Such finesse often depends on practicing other poses to gain adequate flexibility, which allows you to place your center of gravity in the most favorable position. It is important not to try to muscle your way through balancing poses, replacing good alignment with brute force. If you find yourself clenching the floor with your toes, white-knuckled, there’s a good chance you are using too much brawn and not enough brain.

Of course, some one-legged poses, such as Virabhadrasana III and Parivrtta Ardha Chandrasana (Revolved Half Moon Pose), will always require a great deal of muscular action. But if you use alignment wisely in such poses, you can save your strength for where it is needed. And you discern where it is needed by honing your powers of attention.


The price of balance is constant attention. Think of all the actions you must coordinate to remain stable in a pose like Ardha Chandrasana. You must keep your center of gravity under close observation and tight control to maintain its precarious position above its narrow base of support, the standing foot. To manage this, your nervous system must stay on its toes and do some fancy footwork. It keeps repeating three steps: monitoring your position, calculating any necessary corrections, and directing these adjustments.

To monitor your position, your nervous system has to answer the questions “Which way is up?” and “Where is my body?” It has several ways to do this. Before you turn your head to look up in Ardha Chandrasana, your eyes collect data about your position from the horizon line or wall in front of you. The semicircular canals, which are balance organs in the inner ear, also help you find “up” by feeling the downward pull of gravity. And pressure sensors on the bottoms of your feet detect which way you are tilting. To indicate body position, nerve endings in your joints signal the angle of your limbs, trunk, neck, and head. Nerve endings in your muscles and tendons detect force and stretch, and others in your skin detect stretch and pressure. In addition, your eyes provide visual information about the location of various body parts. From all of this sensory input, you can tell whether your body is where you want it to be—for example, whether your lifted leg is too far forward or back for an optimal Ardha Chandrasana. You can also tell not only where you are in space but which way you are moving and how fast.

To calculate corrections, your brain adds up all of this information, compares it with an image of where it wants your body to be, and does some heavy number crunching to decide what movements to make. To direct the needed adjustments, your brain and spinal cord do additional computations and send nerve signals to dozens of muscles, telling them to contract or relax as needed. As you make these movements, your sensory systems constantly monitor the results and start the cycle of correction over again.

That’s a lot of work. No wonder it’s a challenge to balance and chew gum at the same time! Let’s look at how this complex process affects your practice.

If you’re like most people, you depend primarily on visual input to maintain your balance. Have you ever tried balancing on one foot with your eyes closed? If so, the odds are that you couldn’t stay there for long. You’re probably so good at using your eyes for balance that you don’t bother to use the other systems you have available.

Now think about what happens when you practice Ardha Chandrasana outdoors. If you direct your gaze toward the horizon, you can probably balance, but if you turn and look up at the open sky, you may quickly lose your equilibrium. Even though your eyes are open, you no longer see a fixed point of reference to tell you which way is up or which way you are moving.

Another reason it’s hard to look up in Ardha Chandrasana, even indoors, is that turning your head changes the position of the balance organs in your inner ears with respect to gravity. Nerve impulses that used to mean “up” and “down” now mean something different. Your brain needs time to reinterpret all of these messages. If it doesn’t adapt to the new conditions rapidly enough, you may fall over. One way to overcome this problem is to turn your head very slowly and incrementally, pausing to rebalance at various points along the way. Another good approach is to focus your attention on the sensations from your standing foot, ankle, and hip, allowing them to guide your balance as you turn.

Since the brain compares your actual position with an image of where you want to be, it helps to have a pretty precise internal image. And some mental pictures are, of course, more helpful than others. One very useful image is your old friend, the plumb line that runs vertically up from the center of your standing foot. If you can develop a strong internal sense of this line, it will help your nervous system calibrate movements that maintain equilibrium around the line.

In Ardha Chandrasana, it’s helpful to expand the concept of a plumb line to a plumb plane. Imagine that the plumb line lies on a flat, vertical surface, like an infinitely thin wall, that divides your standing foot in half lengthwise and runs up through your body. Concentrate on keeping your head, trunk, pelvis, and both of your legs balanced on either side of this plane. But don’t abandon the plumb line; you still need it to keep your standing leg from leaning too far back toward your heel or forward toward your toes.

At a higher level of the nervous system, your attitude toward practicing balancing poses has a tremendous effect on your success. Approach them seriously and with determination, but also with good humor, patience, and curiosity, like a child learning to stand. If you can laugh when you wobble or fall yet be ready to try the pose again in earnest, you have found true balance in your practice.

Balancing Tips

  • Do one-legged balancing poses on a firm, level surface.
  • Do them early in a practice session, when you are fresh rather than fatigued.
  • Keep your gaze gently fixed on one point.

If you still have trouble balancing:

  • Use a wall for support.
  • Bend both knees before lifting one leg.
  • Keep the knee of your standing leg bent.
  • Put extra weight on the outer edge of your standing foot.

Hold your hands out to your sides like a tightrope walker.


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