Knees often, and unfairly, get the bummed rap. I often hear, "I can't run because I have bad knees." Believe it or not, it's rarely the knee's fault. The knees are merely victims to problems from above or below, a case of being in the wrong place at the wrong time. Kinetic chain dysfunction in the pelvis or hips from above or in the feet or ankles from below, can put the knee in a mechanical disadvantage. It's this mechanical disadvantage occurring over many miles that causes pain in the knee.
I can write a book on knee pain and it's causes, however, I'd like to focus on the pelvis and hips, in particular, the gluteal muscles. The gluteal muscles consist of the most superficial and powerful muscle, Gluteus Maximus, the more lateral muscles, Gluteus Minimus and Medius, as well as several deep hip rotators including the Piriformis. I will focus on the Gluteus Maximus, Medius, and Minimus with the realization that other muscles such as the Tensor Fascia Latae, Deep Hip Rotators (including the Piriformis), Psoas, Rectus Femoris, Abdominals, Hamstrings, and Adductor Group all contribute to pelvic stability.
The Gluteus Maximus
is responsible mostly for powerful hip extension, or pushing the leg back while propelling the body forward or up. Squats, sprinting, jumping are all movements that require a full functioning Gluteus Maximus. Due to reciprocal inhibition (a tight muscles can neurologically weaken the antagonistic muscle), the Gluteus Maximus can underfire because of a tight Psoas (front of the hip muscle). If the Gluteus Maximus cannot perform adequately, then more stress is placed on the knee and muscles surrounding the knee. Think of it this way, the ankle, knee, and hip all have equal responsibilities in performing a squat, jump, or running stride. Take out one area, then there's more stress on the others. Since our bodies will still try to get from point A to point B inspite of an obstacle, we can easily overuse a stressed joint, causing injury and pain.
Let's look at the Gluteus Medius/Minimus
on the right and left leg during a running stride. When you land on your left leg, the left Gluteus Medius/Minimus are responsible (with other muscles) for holding the pelvis level to the ground, not allowing the pelvis to dip to the right side. If these muscles underfire and cannot control the pelvis from dipping to the right, the left IT Band
, which runs down the outside of the thigh and inserts into the outside of the knee, can become overstressed and cause knee pain. The Gluteus Medius/Minimus also controls lateral movement (or sideways translation) of the pelvis. If the pelvis is allowed to move laterally in gait as opposed to being propelled forward, the foot ends up too far underneath the body, causing the leg to cross the midline of the body. This can cause the knee to have undue stress on the inside of the knee and possibly pinch structures on the outside of the knee. It can also cause undue stress on the IT Band.
The RIGHT Gluteus Medius/Minimus (along with other muscles) is then responsible for keeping the leg swinging in a straight path forward and back by not allowing the leg to cross the midline of the body. If the leg does cross the midline of the body when it lands, this can cause knee pain as described above.
The Patella (knee cap) is really like a train on train tracks. The tracks are created by the lower part of the femur (upper thigh bone). So, wherever the femur goes, the patella needs to follow. However, we have many muscles, tendons, and ligaments (including the IT Band) attaching from other areas of the body to the patella, trying to keep the patella on the tracks if the tracks are where they are supposed to be. If the femur bone is not controlled by the gluteal muscles, then the patella will track poorly. A poorly tracking patella can cause grinding and bruising on the underside of the patella.
Again, there are other causes to knee pain such as foot and ankle problems, but if you stabilize the pelvis and hip, you are more likely to recover from and/or prevent knee injuries.