Knee pain can stop you from doing the things you love and can also be a signal indicating imminent injury. It can be a signal that your knee isn't working properly or isn't being used properly.
One possible way to alleviate knee pain is by learning how to operate the knees. And that means learning to control the structures and mechanisms that the knee directly connects to.
When the knee is reasonably straight it's structure is such that the two leg bones, the femur and tibia, can not twist with respect to each other.
However, when the knee is bent, the tibia can slightly twist relative to the thigh bone.
It is this twisting which makes yoga poses like Lotus and Virasana and even Janu Sirsasana C possible. It also means that when standing with the knees slightly bent, that the thigh may be able to move relative to the tibia.
I'd suggest that the most common occasions that can cause knee pain is when you are standing and using your feet and legs to support your body whether standing or moving.
Other occasions where knee pain can occur is while cycling, in which case the legs are being used to provide propulsive force. It may be possible to experience knee pain while swimming also, because of the resistance of water.
In any of these activities knee pain may be caused by the lower leg being twisted repeatedly or excessively relative to the thigh bone. Or it may be due to uneven tension in the connective tissue that crosses or acts on the knee joint.
Until relatively recently the connective tissue network of the body has gone mostly ignored particularly with respect to the musculoskeletal system.
More recent research and exploration indicates that the bodies connective tissue is integral to the functioning of the musculoskeletal system.
How might this relate to knee pain and preventing it?
At least five of these anatomy trains or "myofascial" meridians are present for the entire length of the leg and even the torso.
The deep front line could just be considered the "Deep Line" or the "Internal Line" since it runs up the inside of the legs and up the interior of the body. It could also be thought of as a "Core Line."
The Deep Front Line includes the tibialis posterior which runs up the back of the shin close to the bone. This muscle is important for "picking up" or "pulling up on the inner arch of the foot.
It also includes the quadratus plantae, flexor digitorum longus and flexor halucis longus, all of which act along the bottom of the foot.
It includes the fascia of the popliteus, a muscle which is located just below the back of the knee. The popliteus can help to unlock the back of the knee when that foot is bearing weight.
The deep front line also includes the knee capsule. (Which makes it extremely relevant to fixing knee pain.)
It includes the lowest attachment point of adductor magnus which can act like an extra hamstring muscle, pulling back on the thigh from the sitting bone. The only difference is that this "hamstring" doesn't cross the knee.
It includes the vastus medialis, one of the quadriceps muscle, buried beneath the rectus femoris.
Finally, just below the hip joint it includes fascia of the iliacus and psoas. Both of these muscles cross the front of the pelvis with the former attaching to the inner surface of the pelvis and the latter attaching to the sides of the lumbar spine (as well as its transverse processes.)
This meridian may also include:
Of all of the myofascial meridians, the deep front line is perhaps the most important which is part of the reason that I suggest thinking of it as a core line. However the remaining four listed also have connections between the foot and pelvis making their inclusion relevant in terms of alleviating knee pain.
Note that you can skip over these details if you wish.
If you aren't interested in anatomy the important thing to take from this discussion is that the foot, knee and hip can be tied together by these myofascial meridians.
The lateral line includes peroneus longus and peroneus brevis which run up the sides of each shin causing what Iyengar apparently calls "Racing Stripes" when activated. Both of these are important in shaping the arch of the foot.
The lateral myofascial meridian also includes iliotibial band or fascia latae which runs up the side of the thigh from the tibia and fibula to the top of the pelvis.
It also includes the muscles which act on this band:
While the two sides of the lateral line (left and right) could be though of as opposing each other, I'd also suggest that this line be viewed as complimentary to the deep front line. Where this meridian acts on the outside of each foot and leg, the deep front line can be thought of as having considerable influence on the inner aspect (medial) of the foot and leg.
The superficial back line starts at the plantar fascia, the connective tissue along the sole of the foot. It contains the gastrocnemius and soleus, the bulky muscles at the back of the calf, and then crosses the back of the knee to attach to the hamstrings which run up the back of the thigh to the sitting bones at the base of the pelvis. From there the superficial back line includes the sacro-tubinous ligament which attaches the sitting bones to the sacrum (the technical name for sitting bones is "ischial tuberosity" hence the name of the sacro "tubinous" ligament.)
From there it attaches to the erector spinae, and on up over the head to a point above the eyebrows.
That last bit isn't really relevant to knee pain, what is relevant is that the superficial back line passes up the entire length of the back of each leg, from the sole of the foot to the back of the pelvis.
Opposing or "complementing" the superficial back line in the myofascial network is the Superficial Front Line.
(And please note that superficial doesn't mean superfluous or "shallow." Well actually it does mean shallow, but not in a fake kind of way.)
The superficial front line includes:
Where the superficial back line can be used to bend the body backwards, the front line can be used to bend the body forwards. Together the two can be used to help keep the body upright (though that might be overly simplistic.)
The Lower Spiral Line forms a stirrup for the foot and leg.
Using the sitting bone as a starting point, the spiral line includes the lateral or outer portion of the hamstrings, biceps femoris. The biceps femoris runs down the back of the thigh. At the knee the lower spiral line runs from this muscle to peroneus longus. (And so the spiral line links or has a connection to the lateral line.) Peroneus longus runs down the side of the shin to the outer edge of the foot. Its tendon passes under the foot where it attaches to the tendon of tibialis anterior, which runs up the front of the shin. This muscle is also part of the superficial front line. From the tibialis posterior, the spiral meridian attaches to the iliotibial tract and via it to the tensor fascae latae, which again are both part of the lateral line.
One important thing to realize about fascae is that it transmits tension. Muscles are contained within pockets within the fascial network and when muscles contract they create lines of tension that pull on their respective myofascial meridians.
This same network includes ligaments that tie bones together.
And so muscular tension doesn't just affect the relationship of bones, it also directly affects the joints via ligament tension. (One very interesting read is this article on the elbow as a "tensegrity" structure. It talks about muscles acting in opposition to help "strengthen" the joint they work on.)
But there is more. When muscles activate or relax they don't just affect the relationship of bones and joints, they pull on their part of the connective tissue network which in turn can affect muscles in the same myofascial anatomy train. Myofascial chains can also be affected by the position of bones relative to each other and whether bones are supporting each other or not.
This sounds complicated and it is, if you try to analyze it with a thinking mind. The solution can be relatively simple. Learn how to vary muscle tension and control bone positioning so that the fascial network has balanced tension.
To help eliminate knee pain, maintain good bone positioning (posture) and good muscle tension (not too tight and not too lose.)
Both of these can be maintained by learning to feel and control the body to finer and finer degrees.
Handily enough, the same network that sheaths muscles and transmits muscle tension to bones and to itself can be used to help you feel your muscles and how your bones relate.
The myofascial meridian network is kind of like the USB port on a computer. It transmits force or power (recharging your ipod) causing bones to move relative to each other or remain stable. It also transmits information, allowing you to sense your body so that you can choose how to control it (downloading musical information into your ipod.)
With respect to getting rid of knee pain, you can learn to feel and control your foot and legs, at least as a starting point.
All of the above mentioned myofascial meridians have links to the foot which in turn cross the knee joint. Shaping and controlling the foot can be a first step towards alleviating and preventing knee pain.
Some of the major muscles that act on the foot and shape its arches originate in the shin. I'd suggest that the most important of these are:
These muscles can be used to shape the inner and outer arches of the foot (the "medial" arch and "lateral" arch.) More importantly, in the process of shaping these arches, they can also be used to rotate the shin. Key to rotating the shin is tibialis posterior.
With the foot on the floor (or both feet on the floor) and bearing your weight, you can use tibialis posterior to pick up the inner arch. To pull up on the arch rotate your shin outwards.
How much? That's up to you to decide.
If you tend to have a high inner arch then you probably need to rotate your shin inwards so that your inner arch collapses slightly. If you are flat footed or have a fallen arch or are semi-flat footed as I was, then you can rotate your shin outwards.
First of all, to get a feel for controlling your foot and shin practice rotating your shin outwards and inwards. (Inhale outwards, exhale inwards, and practice moving slowly!) Get used to controlling the rotation of your shin by using your feet (and not your hips). And as you practice rolling your shins out, press down through your big toe (grip the floor) and pull up through your outer arch.
Practice both activating your feet and relaxing it so that you are effectively learning to rotate your shin outwards and inwards. Then, whenever you experience knee pain vary the amount of foot activation and shin rotation to see if you can find a position where your knee pain disappears.
If your knee pain doesn't disappear then we'll have to look a bit deeper but generally when problem solving it's a good idea to start with the easiest thing first. We can then delve deeper from there.
Although this "activation" is easier to do while standing still or while moving slowly, with practice it can be used to better control the feet, ankles and shins while running or cycling or doing other activities. As for actions that cause knee pain while the foot is free, you may find that simply "stiffening" the foot and/or ankle helps.
Although not specifically designed for knee pain, the hip control guide may be useful to help you locate hip muscles and also figure out how to directly control those muscles.
If knee pain isn't being caused by inactive foot muscles then it could originate at the hip.
You can also look at the knee joint article for more information on the knees.
The foot is only the beginning (or one possible beginning) to gaining better control of your body. A key point to remember is that those myofascial meridians or anatomy trains that I talked about above, all of them start (or end or contain) the foot. By learning to "activate" and shape your feet you can help to give these anatomy trains a firm foundation. You may find that you are then able to better control the other parts of your body (and avoid knee pain.)