Rarely a day goes by when I don't see someone running outside. The lovely weather takes exercising outdoors and regardless of body type or experience, running is a low cost option and something we have all done. I often think "Good for you" when I see a runner, but due to my occupation I cannot help but analyze the techniques I see. Is the person running heavy on their feet, striking at the ball of the foot or the heel, are the legs swinging straight through or out to the side, are the knees buckling inward, how are the arms swinging, how much bounce up and down is occurring? If I do see something that seems less than perfect, the next thought I have is "I wonder if they feel pain due to running that way." Now, having less than perfect biomechanics does not always result in pain and it's amazing how much inefficiency the body can tolerate. However, in the absence of prior injury many runners do begin to experience pain due to the repetition of poor mechanics. Knee pain is one such presentation.
The knee is a slave to what the foot/ankle and hip are doing. The long levers of the lower leg and thigh exert much force on the mostly hinging knee joint. Therefore, any movement that occurs at the foot/ankle or hip that is less than ideal can wreak havoc on the knee. Let's start where we make contact with our environment - the ground. When our foot contacts the ground, we should first hit with the outside of our heel and then roll inward, or pronate, as our stride proceeds forward. This pronation is important and normal to dampen the forces that occur at heel strike. Over-pronation, however, is not ideal and causes poor mechanics in the ankle/foot and for the lower leg to rotate inward excessively. This over-rotation is then experienced by the knee and further up the skeleton, often resulting in painful conditions or irritating existing structural damage (e.g. knee osteoarthritis).
With respect to the hip, adequate mobility is needed to allow the desired motions to occur throughout the gait cycle. Stability is also crucial at the hip. Running, and walking for that matter, can be considered controlled falling with alternating single leg standing. As our centre of mass is not balanced over any one of our two hip joints, our bodies would tip sideways if it wasn't for the strength of the muscles on the outside of our hips and sides of our torso. These muscles also control thigh rotation. Therefore, if they are weak, which they notoriously are, due in part to the amount of sitting we do which does not activate these muscles but has them function more as "cushions", you get excessive thigh rotation. Knee pain, once again, is a possible end result.
There a few things to consider which may alleviate and/or prevent knee pain related to running. Be mindful of your knee position when running and try to prevent it from buckling inwards too much. Do you have good shoes with appropriate arch support to prevent over-pronation? Does your hip have sufficient strength or endurance to stabilize itself effectively? There are exercises that can be done to strengthen the appropriate muscles.
Knee pain begs us to at least look at its neighbouring joints. Otherwise, we're just managing symptoms and not getting to the root of the problem. This article is for general information purposes only and is not to be taken as professional medical advice.