Editor's note: The below are intended to be general recommendations for yoga practitioners and teachers. They are not a replacement for the personal advice of a health professional. Yoga teachers should remain within their scope of practice: This means not attempting to diagnose, treat, or offer medical advice to students.
For those with knee sensitivity or injuries, some common yoga poses can be inaccessible or uncomfortable. Fortunately, knee discomfort, as well as the risk of knee injury, can often be reduced through attention to alignment, a focus on particularly beneficial poses, and some simple modifications of others.
Knee discomfort “may be due to trauma, prior surgery, arthritis, pre-existing injury of the cartilage (meniscus) or ligaments, or patellofemoral tracking issues like chondromolacia patellae, or total knee replacement,” says physical therapist Bill Reif, author of The Back Pain Secret: The Real Cause of Women's Back Pain and How to Treat It. He emphasizes that yoga practitioners with knee sensitivity should always check in with their doctors for diagnosis and personalized movement recommendations. And those who have had knee surgery should always follow the recommendation of their surgeons as to when it’s advisable to begin or return to yoga.
Reif says that for those with underlying knee conditions who have received a doctor’s green light to exercise, “Yoga could be good or bad.” Previous knee injury is a risk factor for a new knee injury, and yoga itself can place unusual demands on the knees. A 2012 study indicated that yoga may lead to meniscus tears and may carry more risk for the knees than jogging and climbing hills. Reif wonders if that risk might be because some yoga poses, like pigeon and lotus, can torque the knees (especially if we didn’t grow up doing those poses). “Pushing these poses too much and too soon could lead to stress of cartilage and ligaments of the knee," he says.
However, yoga can also benefit the knees. For instance, studies are showing that yoga can reduce knee pain and improve mobility in those with osteoarthritis of the knees (and also improve the mood of those with knee pain!).
Yoga’s ability to benefit the knees may depend not only on which poses we do, but on how we do them.
The Knee Alignment and Actions That Matter
Knee alignment is especially important for those with knee issues. Reif explains that when knees are misaligned, “you risk tearing the internal structures such as the meniscus, but when in good alignment you strengthen the muscles surrounding the joint.”
Researchers have found that even minor misalignments of the knee can cause uneven pressure distribution throughout the joint, contributing to the deterioration of cartilage and to problems like osteoarthritis (OA). This suggests the importance of paying attention to alignment both in and outside of yoga class.
For optimal knee health, those who routinely experience knee discomfort could try the following suggestions on for size.
1. Avoid hyperextending your knees.
Repeatedly moving your knees “beyond” straight may degrade joint stability. For example, ACL injury is more likely to occur in those who hyperextend their knees. When you hyperextend, “you are no longer relying on muscles and [instead] fully relying on ligaments,” Reif says. “Over time, this may overstretch ligaments, reducing their vital protective function.”
Hyperextension in yoga could be particularly important to pay attention to, both because of the fact that we regularly do poses in which it is likely, and also because we often ask the hyperextended leg to take an unusual amount of weight. For instance, in triangle, the front leg, which so often hyperextends because of gravity, is supporting most of the body’s weight. In standing balance poses, a hyperextending leg may take all of the body’s weight. Students may then hold these poses for long periods, or place their hands on the shin of the hyperextended leg, increasing the stress to ligaments. (In Reif’s view, those with knee pain are better off avoiding this additional stress on knee ligaments.)
While it’s true that some minor hyperextension—the few degrees that occur when walking, for example—is generally not a problem for most people, Reif believes that it’s very difficult to tell what’s excessive. “Hyperextending the knees beyond about 10 degrees should be avoided,” says Reif. “But even as a PT I cannot ascertain that small a degree without a goniometer [angle measuring device].”
The difference between a safe amount of hyperextension and an “excessive” amount is hard to feel as well as see. Hyperextension often occurs without instant discomfort, and it may take a day or more for any soreness to be perceived (if it comes at all). Reif says that it is only if someone were to experience drastic, abrupt hyperextension—the sort that could arise from a contact injury in soccer, for example—“would they experience immediate pain and inflammation.”
“Micro-bend the knee,” “Don’t lock the knee,” and “Don’t go past straight” are often helpful cues, as it can be difficult for yoga students or teachers to ascertain in the moment how much hyperextension is too much. Reif clarifies that “These generic cues err on the side of caution.” In his view, it’s important for teachers to use caution with students who have expressed that they have knee issues, as well as with students in the room who may have knee issues about which neither they nor their teachers are aware. To him, hyperextension is a risk-reward issue, one not worth the risk because the benefits of hyperextension are minimal.
In upright positions, be aware of the position of your shin bones. (When you are standing straight, the shin bones should be vertical, not slanting back, which would signal hyperextension.
2. Track the [true] center of your knees toward the center of your feet.
“Ideally,” says Reif, “the knee should track toward the middle toe.” In a standing pose like mountain, and while walking, the toes point generally forward, and the knees point forward, too (toward the centers of the feet). If the toes point one way, while the knees point another, the knees will be forced to rotate—a movement for which these hinge joints have only a limited range.
Reif adds that “The kneecap is not a reliable indicator of alignment as there is a variance in ‘normal anatomy’ and the patella moves easily and can be pulled off track by muscular imbalances.” A better focus might be the centerpoint of the entire knee (which may or may not be the centerpoint of the kneecap). Instead of focusing on your kneecap, identify the midpoint between your inner and outer thigh. Track the center of your thigh toward the center of your foot.
3. Avoid “sickling” your feet.
“Supination or ‘sickling’ of the front foot can put added stress on the outside of the knee,” says Reif. The feet can easily sickle in poses like cobra and camel. Instead of letting the heels turn out while the toes point in, aim to keep your feet parallel in these poses, reaching back evenly through the bases of the big toes as well as the bases of the little toes. In poses like figure four (pictured below), dorsiflexing the ankles (i.e., moving the ball of your top foot toward your top shin) can prevent sickling.
4. Hip hinge before bending the knees to come into chair pose.
The transition into squats matters to the knees more than where the knees are in relation to the toes, according to Reif.
In chair pose, students may be used to being told “Don’t let your knees go past your toes,” but researchers suggest that the knees should be allowed to move past the toes when squatting “to optimize the forces at all involved joints.” According to Reif, “It’s not so much a deeper bend that’s the problem; it’s the sequence of bending the knees first with the load from above that’s the issue here.” He explains that bending the knees before hinging from the hips (for example, in an attempt to stay more upright for the Ashtanga version of chair pose), may lead to knee discomfort.
“Instead, sit back first,” advises Reif. “You’ll have more control over your center of gravity. Allowing the hip flexion to initiate the squat will take stress off of the knees by centering the torso over the feet, counterbalancing the weight of the pelvis moving back. You should be able to keep your feet grounded; this way the tibia does not slide forward on the femur, which is stressful to the ACL. And the farther you dip into flexion, more patellae surface is in contact with the femur, decreasing knee pressure.”
According to Reif, the initial goal of the instruction in chair pose to “not let the knees pass the toes” may have been to get students to sit back and hinge from the hips, rather than coming into the pose knee-first. “It’s okay to let the knees move beyond the toes as long as the sequence is initiated from the hip hinge first,” he concludes.
In summary, a better cue for a student with knee issues might be, “When coming into chair, sit back and then bend your knees.”
Benefitting the Knees
To make any yoga practice especially beneficial for your knees, emphasize poses that increase strength and flexibility in certain muscles.
1. Strengthen the quadriceps.
Since quadriceps strengthening may help reduce knee pain, Reif feels that building strength in this muscle group is of highest priority for those with sensitive or injured knees. Reif explains the importance of the quadriceps to healthy knee tracking: “If the quadriceps are weak there may be an uneven pull on the patellae (kneecaps), possibly causing tracking issues and crepitus [knee clicking].”
For those with knee issues, Reif recommends strengthening the quadriceps through multiple repetitions of low-resistance movements, especially those that strengthen the vastus medialis oblique (VMO). “Limiting extension [of the knee joint] gives more attention to the VMO, the smallest and often the weakest of the quadriceps,” says Reif.
For instance, while seated in staff pose, press the backs of your knees down into a rolled-up yoga mat while keeping your heels on the floor and toes and knees pointing up toward the ceiling. Repeat this action one to two dozen times, pressing your knees down for a breath or two each time.
2. Strengthen the hips.
Studies show the effectiveness of strengthening the hip muscles (such as the external rotators and abductors) in reducing knee pain—perhaps because, as Reif mentions, “These muscles also help to direct the thighs.”
Warrior II and extended side angle strengthen these hip muscles. So does the action of pressing the legs outward into a strap while in mountain pose—one of many hip-strengthening strategies described in this sequence (which addresses, among other things, knee pain that may be caused by knees that track inward).
3. Strengthen the core.
Interestingly, strengthening the core as well as the hips has recently shown to be even more effective at lessening knee discomfort than strengthening the muscles right around the knee. “Better control over these muscles may reduce the load on the knee,” says Reif.
Plank, side plank, and supine leg lifts are among the many core-strengthening yoga poses and movements. Even focusing on stabilizing in a standing balance pose before lifting a foot can improve core strength.
4. Stretch the hamstrings.
“Stretching hamstrings may also help to reduce knee discomfort and clicking,” says Reif. “It’s necessary to create balance between the quadriceps and hamstrings for knee functioning and stability,” he says. He explains further: “If your hamstrings are tight,” (and they are, for many with knee pain) “you may not be able to fully straighten the knees, and this loss of extension does not allow the kneecaps to freely float the way they should when walking, climbing, and squatting.” Tight hamstrings may also cause pronation at the ankles, stressing the knee joint.
Many yoga poses (from hand to foot pose to pyramid pose and forward folds) target the hamstrings. Those with unrelenting hamstrings may find that that alignment work and a PNF approach (stretching via proprioceptive neuromuscular facilitation) helps relieve hamstring tension and increase range of motion.
5. Release the iliotibial (IT) band.
The IT band, a thickened area of fascia along the outer thigh, stabilizes the knee and helps with hip movements. It can grow very tight in walkers and runners, and, according to Reif, in those who “over-rotate the foot, ankle, and/or entire leg inward.” Repetitive demands on the IT band may lead to iliotibial band syndrome, frequently the cause of knee pain in runners. Releasing it may be part of the formula for relieving some knee pain.
Reif explains that while the IT band itself “does not yield much,” certain techniques and poses can help it to move more freely. “The IT band may be effectively released with a foam roller, massage stick, or through bodywork like cross-fiber massage,” says Reif. Poses like half lord of the fishes (ardha matsyendrasana), and lying supine, placing a strap around your foot, and drawing one leg toward the opposite shoulder for a version of hand to foot pose, also target the IT band and surrounding areas.
Supporting Your Knees in Yoga Practice and Daily life
You can regularly practice the aligning, stretching, and strengthening described above and make any type of yoga practice more comfortable with these modifications. If your knee issues derive from knees that veer inward (a misalignment commonly called “knock-knees,” but more precisely a “high Q angle”), also check out A Leg-Activating Sequence to Address a Common Misalignment.
The benefits to your knees may be greater if, in daily life as well as in yoga class, you work to maintain the knee alignment described above. Notice if you hyperextend your knees while standing, and instead bend your knees slightly. When walking and climbing stairs, point your toes roughly forward, and track your knees toward the center toes. Even when driving, keep your toes and knees aligned.
Certainly avoid positions that place pressure on your knees and cause discomfort. Since full squats and kneeling may be compressive, when you must come close to the floor—whether it’s to lay tile or play with children—you may want to consider sitting instead, or finding another comfortable position that works for you.
Notice the effects of this attention on your knees, as well as the broader effects. Does your gait become smoother? Your base of support more stable? Are there any changes in how your feet and hips feel? In how you breathe? We often find that the benefits of a small change can ripple outward...and keep rippling.