Tuesday, April 5, 2011

A royal pain in the...knee?

Knee pain is one of the most common overuse injuries that afflict people. Slow developing, overuse knee pain can have a slew of causes. But with just a few quick exercises to add to your day, you can prevent knee pain from slowing you down!

First off lets take a look at the anatomy of the knee.

The upper leg bone (femur) ends in the shape of two big knobs. These are called condyle's with the one to the inside of your leg being medial and the one to the outside being lateral. On top of these sit the patella (knee cap). The knee cap slides up and down the groove as we flex and extend our knee. It helps to think of the knee cap as a train and the femoral groove as the tracks.

Usually the patella runs smoothly up and down the track. However, as is usually the case with overuse injury knee pain, the patella gets pulled to one side or the other.

As you can see in the picture, there are quite a few muscles that affect the knee. If one of these muscles begins to tighten up due to overuse, or if one becomes weak, the patella will be pulled to the side of the stronger muscle. As a result it is very important to keep the muscles that directly affect the patella flexible.

There are also indirect factors that can cause knee pain. The two most common are immobile ankles (tight calves) and immobile hips (tight/weak glutes).

I'll start with tight calves first. Basically the muscles of the calf regulate the ability of the ankle to move. If the ankle cannot move into a dorsiflexion position (foot comes up towards the shin) then during squatting the knees will suffer from an increase in shearing force. Shearing force occurs when one bone (the femur) has energy moving in a sliding force across an adjacent bone (tibia). As a result the knees will suffer a lot of pain as the passive tissues attempt to prevent the shearing force from actually causing movement.

The muscles at the hips on the other hand control the rotation of the femur. If the muscles at the hips get weak they will allow the femur to rotate internally. When this happens, again the patella will not track correctly in the femoral groove. As a result the patella will get irritated as the added friction will begin to wear on the back side of the patella.

So what can we do to keep these things from happening?

Soleus Stretch
Beginning with the calves, simple calf stretching daily for a total of 60-90 seconds will help keep the calves flexible. Most important is stretching the lower calf. To do this we lean against a wall as if attempting to push it over. This will stretch the back leg. Then simply bend the back knee slightly while keeping the heel of the back foot on the ground. Hold this for :15-20 seconds and repeat 3 times on each leg.

To stretch the glutes you do a seated glute stretch by sitting in a chair and laying your ankle across the opposite knee, sit up with a tall posture and lean forward from the hip. You should feel a stretch in the hip of the leg that is off the ground.

Split Squats
For strengthening, simple hip bridges, single leg Romanian Dead Lift and split squats work well. Just be sure to push through the heel of the foot that is doing the work. 

Next week we will look at common back injuries and how you can prevent them.

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