Yoga anatomy to protect and cure your knee
In this article I will explain some of the knee anatomy, as well as its relation to other part of the body and also many alignment tips and key principles to practice yoga safely and effectively.
The kneecap is a hinge joint, which means is designed to slide along a groove in the femur (flexion and extension), and it has to move smoothly within that groove to do its job well. If it goes “off track” (rotation, sideways, and it often does), it grinds away at the cartilage underneath and destabilizes the knee. The ensuing wear and tear is a key reason for knee replacement surgery, which a lot of people believe is necessary because they think the cartilage is “gone.” But the truth is that cartilage can grow back, albeit slowly. The main problem is that if we don’t correct the imbalances, we will continue to grind our cartilage down faster than our body can replenish it.
There are also no bones elements in the knee area, only the ligaments and muscles stabilize and fix it, which means we have to pay attention to engage these muscles and keep the ligaments healthy.
Knee pain is primarily associated with the weakness of the vastus medialis obliquus (VMO). When the VMO is weak, the patella is more likely to drift out of alignment. Besides strenghtening the VMO it is equally important to improve flexibility in the quads, in particular the rectus femoris, which crosses the hip and the patella. When this quad muscle is tight, as is common with most people, it can inhibit kneecap mobility and prohibit proper kneecap alignment, leading to abnormally high pressure where the patella connects to the femur. But when you keep that muscle flexible, the kneecap is free to move as it should.
When it comes to knee health we also have to speak about the importance of the core, hip abductors (outer hips) and glutes muscle. To understand how these muscles affect the knee joint, it’s helpful to think of the knee in the context of the entire leg and pelvis. The patella is a mobile bone structure between the foot and the pelvis; any wobble that travels up from the foot or down from the pelvis affects the patella. While instability in the foot or ankle can contribute to knee pain and dysfunction, it’s a less likely culprit than instability in the pelvis—which is where a strong core, hip abductors, and glutes come into play.
These three muscle groups all surround the pelvic bowl, which means the stronger and stabler they are, the stabler the pelvis will be. This is important, because the orientation of the femur (thighbone) at the hip joint causes a small degree of normal rotation at the knee joint during flexion and extension. However, any pelvic instability caused by imbalances in the core, hip abductors, and/or glute muscles creates pressure that travels to the knee, leading to abnormal wear and tear that can potentially cause chronic pain. For example, internally rotated femurs create a knock-kneed position, called valgus, an angle that’s frequently associated with anterior knee pain. Strengthening the hip extensors, which externally rotate the femurs, helps to counterbalance this pain-inducing angle.
The foot has three arches, these arches are crucial in giving the feet flexibility, absorbing shock, adapting the feet to the different surfaces they encounter and distributing the weight of the body. These arches are also important to know about in your yoga practice because they influence the foundation and alignment of the rest of the pose.
medial longitudinal arch: this arch runs along the length of the instep, from the big toe side of the foot to the heel. This arch doesn’t touch the ground and is most involved in weight bearing activities.
lateral longitudinal arch: this runs along the length of the pinky side of the foot. Its mostly involved in propulsion and it does touch the floor.
the transverse arch: this runs round from the lateral to the medial side of the foot (outside to the inside of the foot). Just behind the ball of the foot.
In standing poses we must try and keep the arches engaged. When you keep the arches engaged (and refrain from collapsing them) this strengthens the arches and creates a solid foundation for the rest of the pose.
Distribution of weight
In your standing poses, a general rule for most poses is that half of the weight should fall on the heel and the other half is divided over the ball of the big and little toe. Making sure your feet are flexible and strong in all ranges of motion through different poses will make sure your feet can keep up their important role of looking after a solid well aligned foundation for the rest of the body in the pose.
The poses and cues below will go a long way toward helping you stabilize your pelvis by strengthening your core, outer hips, and glutes, as well as by releasing tension from the quadriceps. The result? Happy, healthy, pain-free knees.
In all yoga poses our first focus point is always on the foundation, what is on the ground.
1) Knee and Foot in line
Heading in the same direction.... To keep your knees safe you want them to be in the right alignment with the feet. So in Warrior II or Extended side angle pose, it is genearally best to keep the knee pointing over the centre of the foot, and to avoid the natural tendency of the knee pointing inward of the foot. As yoga teachers we often say something like: “Turn the knee towards the little toes side of the foot.” As a result your femur will rotate outward to make that happen and your knee ends up in the right place with regards to the foot.
2) Dont allow the knee to twist or side bend
You generally don’t want any twisting or side bending in the knee joint...... Basically what you want to remember is that we don’t want our knee joint to do any twisting and side bending generally speaking. The knees are not so suitable for that. So as long as the knee and the centre of the foot are pointing in the same direction, and there is a clear path of weight down through the feet balanced over the 3 points, you are keeping your joints healthy.
For example in Warrior I, it is easy to collapse the medial longitudinal arch. But if you do, you twist the knee. So pay attention to turning the back foot in enough, so that you can keep grounding the 3 points down and the weight stays divided over the ball and the heel of the foot. This way your arch stays lifted, your knee stays safe and your pose comes alive!
For example in Trikonasana (Triangle pose) the front knee cap should point over the centre of the foot. This requires a strong outward rotation of the femur bone in the hip socket, to align the femur with the shin and foot. If the outward rotation isn’t happening, the knee will point inward and there will be a twist happening in the knee joint. Which is where the femur and lower leg bone come together.
3) Engage your Quadriceps
Strong Quadriceps are a must..... You know your quadriceps (muscles along the front of the thighs) are active and engaged when you cannot move your knee cap around. Try this, sit with your legs extended out in front of you, relax our legs and hold the knee caps on both sides. As long as you keep the leg muscles relaxed, you can move your knee caps around. The moment you engage your upper leg muscles (quadriceps) you cannot move the knee cap anymore and it’s stable.
This tells you that the strength in the quadriceps is very important in supporting the knee joint, including the knee cap, which is in fact embedded in the quadriceps tendon. An engaged and strong quadricep helps to stabilise the femur and shin bone and bring them in proper alignement with regards to each other. So please make sure you engage your quadriceps in your standing poses, and even most seated poses, to keep the knee joints healthy and protected.
4) Avoid over extending your knee joint.
For example in Trikonasana when straigtening the leg support the front of the knee with the quadriceps muscles. Next step try to feel the support at the inner knee, outer knee and back of the knee.
If you do end up feeling strain in the knees, back out of the pose and experiment to see if you can change the pose to that degree that you feel the stretch in your hips or groins instead.
1) Shin and Femur aligned
In seated poses it is also important to keep the alignment of the shin bone and femur bone straight. So for example in Virasana, sitting on your knees with your toes pointing out (instead of back) creates again a twist in the knees that isn’t very healthy and destabilising for most people.
2) Open Hips - reduces stress on the knees
The moment you come into hip opening poses, like Lotus pose (Padmasana) or Eka pada Kapotasana (Pigeon pose), something else is happening as well. We need the hips to be open (for those poses, again a strong outward rotated femur bone is needed in the hip socket). This opening really needs to come from the hip joint. If not it is going to be compensated by the knee joint and once again we end up twisting and side bending the knee joint as a result.
When your hips are stiff, the knees will try and compensate as a result. If you are not aware of this mechanism of the knee joint compensating you will put your knees at unnecessary risk and they will suffer.
Remember that with hip opening poses you should not feel the work in your knees. If you do - come out of the pose and go less deep, or find an alternative position.