Tuesday, March 29, 2016

Runner's Knee

One type of knee pain is patellofemoral joint pain. This occurs when the tissues on the underside of the patella ( the knee cap) is inflamed causing pain. It plagues many runners limiting their training and sidelining them from racing. When the area is really aggravated, it can hurt to sit and negotiate stars.  The patella and the femur (thigh bone) make up the patellofemoral joint. When the knee bends, the patella slides up and down in a groove of the femur. There are several ways the patellofemoral joint can be aggravated. There can be compression from the quadriceps (which can also lead to patella tendonitis),  lateral compression from the illiotibial band (ITB) and poor mechanics.


Quadriceps Compression 

The patella 'floats' in the connective tissue of the quadriceps. The quadriceps transitions into the quadriceps tendon then attaches to the patella then becomes the patella tendon. When the quadriceps are over worked, it puts an increase pull to the tendons. The tension from the tendons compresses the patella into the femoral groove resulting in grinding. The grinding causes degeneration of the tissue  behind the patella leading to pain and arthritis.


Lateral compression 

Due to imbalance of muscles, the tissue on the lateral (outside) of the thigh can get stiff pulling on the the patella. This structure is known as the ITB. The ITB has fibers which attach to the patella. Cadaver studies have shown a variation in how much of the ITB tissue attaches to the patella. You can't stretch the ITB because it is not a muscle, it is fascia. There is no elastic tissue to stretch.  This is why foam rolling is so important ( we'll get to that in a minute). When the ITB pulls on the knee cap it cause pain on the either side of the knee cap.  The lateral tissue pull the kneecap to the outside which can  stretch the medial structures causing pain on the inside. On the other hand, the pull of the ITB can cause the knee cap to rub again the femur causing pain on the outside of the knee. Stiffness of the ITB can be a result of poor muscle activation.


"The knee is a stupid joint."- Gary Gray. It is influenced by the hip from the top down and the ankle from the bottom up. The knee comprises of the tibia (shin) and femur. These bones make up the ankle and hip respectively. Any biomechanical deviations above and below has a direct affect on the knee.

Pronation of the foot is normal in the stance phase. However, excessive or prolonged pronation leads to injury. When the foot over-pronates, the foot rolls towards the ground bringing ankle joint in. The tibia (shin bone) follows along. Since the tibia makes up the knee, the knee follows along and collapses inward. This is called the valgus position and causes abnormal stress to the knee. 


From the top down, the gluteal muscles can play a role in knee pain. The gluteals originate from the pelvis and attaches to the thigh bone. When the glute muscles contracts, the femur (thigh) bone rotates keeping the knee forward. Activation of this muscle keeps the femur aligned forward and the knee in a good line of pull. However, when there is weakness of the gluteals, the femur is allowed to drift inward. This causes the knee to fall inward, again, causing increase stress to the knee.


What to do now?

Foam rolling is a type of myofascial release. The science is unclear on it's exact mechanism. My belief is the compression provided restores fluid ( think about squeezing a kitchen sponge) between the connective tissues which improves the ability for the tissues to slide. It is good at managing symptoms but will not get to the root source. There is a reason why the muscles and tissues get unusually tight. Foam rolling  is still beneficial because you want the muscles and connective tissue slide better. For quadriceps compression roll over the quadriceps and for lateral compression roll over the ITB.
*** For the optimal benefits make sure you are hydrated when foam rolling. 

Long term


Research has shown glute strength has a direct affect on knee pain. Due to the attachment of the gluteals, it has direct control of the femur.  Proper glute strength and activation keeps the femur in a forward position. This aligns the femur the the patella can stay within it's groove. This leads to less strain in the knee joint. However, when the glutes are weak, the femur is allowed to roll inward which leads to mis-aligned position increasing stress to the knee. Also, energy absorption from ground forces is more evenly dispersed to the glutes and away from the knees. I have written posts on glute strengthening exercises.

Limited ankle dorsiflexion is a contributing factor in foot pronation which can impact knee position. Dorsiflexion is the ability to pull the foot towards your body. While you are running, as your foot hits the ground, your shin moves over the ankle as the knee bents. This movement is also ankle dorsiflexion. If there is inadequate ankle dorsiflexion, the foot will pronate to compensate for the loss of movement. In a tight ankle the tibia comes forward but there is a stop in the ankle. Momentum will carry that energy forward in the form of foot pronation. Due to the bony structure of the ankle, when the foot pronates the ankle with rotate along with the tibia. This will result in knee valgus (see above picture) leading to increase stress to the knee. In order to resolve the mechanics from the ground up you have to perform ankle mobilizations to loosen up the joint then restrengthen the foot. Here is a video to demonstrate ankle exercises.


Running form has a big influence on injuries. Over striding places a bigger emphasis on using the quadriceps for propulsion. This leads over use injuries  of the quadriceps.  Over-striding brings the ground reaction forces in front of the knee creating more strain in that joint. People who over stride tend to be heel strikers. Research has shown that heel strikers have more knee pain then forefoot strikers. By heel striking, the ground reaction forces goes anteriorly placing more stress on shin, knees and quadriceps. However, forefoot running brings the body over the ground reaction forces which allows the energy to be disperse through the entire leg. This occurs because the body mass is over the foot. Meanwhile in heel strike the body is behind the knee, which makes the quadriceps work harder to propel the body over the foot.

Proper forefoot strike also works the muscles (tibialis posterior) that hold up the arch limiting the amount of pronation. This leads to better knee alignment. BUT beware, if there is weakness of the muscles you can get aches and pains in the lower leg in the transition. Having good core strength takes the pressure off the lower leg.

My recent post discusses the benefits of forefoot running.

Our body is all connected. The regions above and below the pain typically contributes to injury.

Please contact me if you have any questions.

Kulmala JPAvela JPasanen KParkkari JForefoot strikers exhibit lower running-induced 

knee loading than rearfoot strikers. Med Sci Sports Exerc. 2013 Dec;45(12):2306-13.

Daoud, Adam I., et al. "Foot strike and injury rates in endurance runners: a retrospective study." Med Sci Sports Exerc 44.7 (2012): 1325-34.

Saturday, March 12, 2016

30 day 3D Exercise Challenge

While I'm working on my next post, I'm going to do a 30 day 3D exercise challenge on my Instagram starting 3/13/15 (3drunner, also link located on the right). 

What  is 3D? Our body moves in 3 main planes of motion - sagittal, frontal and transverse ( forward/back, R/L and twist). And our muscles, joints, bones are 3 dimensional! Unfortunately a majority of us assess, treat and train primarily in the sagittal plane while the frontal and transverse planes are under utilized. In running (and walking), we move in the sagittal plane, but the other planes work to support forward movement. I think weakness of frontal and transverse planes leads to early fatigue and even injury. Performing exercises with the 3 dimensions in mind strengthens more muscle fibers!