Twists and Triangles
Knees love alignment. Yoga promotes alignment. Therefore, knees love yoga. The knee joint is deceptively simple. Essentially, it is the junction between the thighbone (femur) and the shinbone (tibia). When you stand and stack these bones correctly, they bear your weight effortlessly, distributing the downward pressure of the femur evenly over the top surface of the tibia so that no particular point suffers too much compression. In this optimal position, there aren't any big gaps between the bones, so the ligaments, muscles, and other connective tissue that hold the knee together do not overstretch. It's only when you disturb this alignment that trouble begins.
Because Utthita Trikonasana (Extended Triangle Pose) is relatively simple and accessible, you're likely to learn it very early on in your training and practice it more often than its counterpart, Parivrtta Trikonasana (Revolved Triangle Pose), which requires that you have more flexibility and balance. But if you regularly practice Extended Triangle without including Revolved Triangle, you could gradually open excess space between the bones of the inner knees and close the corresponding space on the outer knees. Over time, this could shift more of your weight onto the outer side of your knee joints, causing excessive wear on the cartilage of the outer knee (the lateral meniscus).
You could also overstretch the ligament that binds your inner knee bones together (the medial collateral ligament) and stress the cartilage of the inner knee (the medial meniscus), which is attached to that ligament.
Balance Inside and Out
By including Parivrtta Trikonasana as a regular part of your Triangle practice, you can fine-tune the inner-outer balance of your knees, creating a precise alignment of the thighbones with the shinbones and promoting the overall health of the tissues that keep the knee joints functioning properly. To do this, you'll need to learn how to use your gluteus maximus—the major muscle of the buttock—to control the movement of your pelvis.
The gluteus maximus is anchored to the back of the pelvis and the sacrum, and its fibers run diagonally down and forward from there. Some of the glute's fibers attach to the back of your upper thighbone, but most attach to a band of connective tissue that runs down the entire length of your outer thigh from the top of the pelvis (the ilium) to the outside of the tibia just below the knee. This strip of tissue is known as the iliotibial band (often called the IT band).
When you practice Utthita Trikonasana with your right leg forward, you contract your right gluteus maximus in order to help rotate your right leg outward. Contracting the right glute in this case also enables another essential action in the pose: It allows you to lift the left side of the pelvis up and back. Although this contraction is necessary to make the pose work properly, it also creates the imbalance between the inner and outer knee. As the glute contracts, it draws the iliotibial band taut, so it pulls the bones of the outer knee closer together.
Meanwhile, the gluteus-powered lift of the pelvis stretches the gracilis, a muscle shaped like a strap that starts at the pubic bone, runs down the inner thigh, crosses the inner knee, and attaches to the inner side of the tibia below the knee. The gracilis ordinarily helps hold the bones of the inner knee close to one another, so loosening it (by stretching it out) tends to open space between these bones. When you practice Utthita Trikonasana repeatedly without counterbalancing it with other poses, it tends to make your gluteus maximus stronger and tighter, while making your gracilis weaker and looser. This can make the gap between your inner knee bones larger and the gap between your outer knee bones smaller.
Stretching and Strengthening
To prevent this imbalance, practice poses that lengthen the gluteus maximus without weakening it. Revolved Triangle is ideal for this because it simultaneously stretches and strengthens the muscle, providing just enough release on the outer knee to relieve compression that could cause excessive wear on the lateral meniscus, while maintaining the necessary tension on the IT band to hold the outer knee together. You can begin to understand the stretching and strengthening of your gluteus maximus by rotating the upper side of your pelvis down and forward from Utthita Trikonasana to Parivrtta Trikonasana. Your pubic bone moves toward your inner knee, so the gracilis immediately goes slack. The back of your pelvis shifts farther from the iliotibial band, causing the gluteus maximus to stretch more and more. But during this movement the gluteus maximus is the primary muscle supporting your pelvis, so in order to lower the pelvis smoothly, you have to release the muscle's tension in a controlled way. In other words, you have to keep the muscle partially contracting even while it is lengthening. This action, called eccentric contraction, strengthens the muscle even while it's stretching and trains the muscle to maintain its strength over the entire range of the stretch.
As you learn to regulate the descent of your pelvis into Parivrtta Trikonasana, you'll gain fine control over both the tension and the length of the gluteus maximus. You can then choose the exact amount of tension this muscle places on your iliotibial band and deliberately decrease or increase the tension on your outer knee until it's in balance with your inner knee. This will help your shinbone line up perfectly with your thighbone, and will keep your knee in balance and happy.
You'll feel how the two Triangle Poses complement each other by moving directly from Extended to Revolved, and then back to Extended Triangle again, keeping one hand on the gluteus maximus of your front leg and the other on the hip of your back leg.
Contraction in Action
Stand so that your feet are parallel and about four feet apart. Turn your left foot in slightly and turn your right foot out about 90 degrees. Place your left hand on the top of your pelvic bone on the left side and your right hand over your right gluteus maximus.
You'll use your right hand to feel the contraction of your right glute and help guide the fine-tuning of this contraction in Extended Triangle. Now tighten your right gluteus maximus as firmly as you can. To enhance the contraction, keep the sole of your right foot firmly in place on the floor, push your right foot toward the right as if you were trying to slide it along the floor, and rotate your right knee outward. At the same time, lift your left hip up and back until it stops. Continue these actions as you slowly bend sideways at your right hip joint to lower your pelvis and torso horizontally over your right leg.
As you move, continue contracting your gluteus maximus. Press your fingers into the muscle, and if the muscle releases, stop and contract it again before moving further into the pose. You should feel a stretch on your right inner thigh. Increase this stretch by lifting your left hip up and back and tightening your right gluteus maximus. Notice that the more you do this, the more your right inner knee opens and your right outer knee closes.
Next, without changing your hand position and while still maintaining the contraction of the right gluteus maximus, gradually move from Extended to Revolved Triangle. Rotate your left leg in to move your left heel farther back. With your left hand, slowly guide the left side of your pelvis down and forward toward your right foot until the left and right hip joints are parallel to the floor and your left hip is as far forward as your right. (You may need to step your left foot in slightly to do this.) Allow your trunk to rotate along with your pelvis. As you move, use the sensitivity of your right hand to feel that the right gluteus maximus is maintaining the eccentric contraction; it's still contracting firmly, but at the same time it's also lengthening.
Feel how, in contrast to Utthita Trikonasana, Parivrtta Trikonasana releases tension from your inner knee and puts more tension on your outer knee. Now increase this tension by dropping your left hip slightly below the level of your right hip. This stretches the gluteus maximus even further. Place your left hand on a chair, a block, or the floor outside your right foot, but keep your right hand where it is. Rotate your trunk toward the right as far as you comfortably can into the pose.
Put It All Together
You'll continue to feel your right gluteus maximus contract under the fingertips of your right hand as you move back from Revolved to Extended Triangle. Use the strength of your glute to simultaneously rotate your right knee outward and lift the left side of your pelvis up and back as far as it will go. Allow your trunk to follow the pelvic movement to create the classic Extended Triangle position. As you make this transition, feel your right outer knee shorten while the inner knee lengthens. Exit the pose by lifting your torso upright; then pivot on your feet and practice this sequence on the left side.
Although it's important to complement Utthita Trikonasana with Parivrtta Trikonasana, you don't have to practice the poses one after the other, on the same day, or for the same duration or the same number of times. But if you include one variation of Triangle Pose consistently in your practice, it's a good idea to include the other on a regular basis as well. In time, you'll develop a sense of what it feels like to keep the inside and the outside of your knees equally strong and flexible. Then you will know, deep down in your bones, that yoga loves knees.
Roger Cole, Ph.D., is a certified Iyengar Yoga teacher and a research scientist specializing in the physiology of relaxation, sleep, and biological rhythms. He trains yoga teachers and students in the anatomy, physiology, and practice of asana and pranayama. He teaches workshops worldwide. For more information, visit http://rogercoleyoga.com.