If your legs remain too bent throughout the running gait, you are prone to stressing your quads too much and 'turning off' or not using crucial muscles very well - all leading to a vicious cycle of dysfunction:
Common knee issues can result, due to the tight quads pulling on the knee, causing poor tracking - the pain!
This also causes the hip flexors to over work, causing tightness and the inability to utilize your glutes for strength AND stability. You can be the strongest in the weight room, but if you are not firing and using muscles appropriately, this strength goes for not and will continue to cause imbalances.
We have been brainwashed into thinking the more we run the tighter we get or the more unhealthy it is. This is wrong. As runners, we do not have to be chronically tight, with aches and pains. Every running step "can be" an opportunity for strength and health.
WHAT CAN YOU DO
One way to help turn this around is to include short, steep, powerful hill repeats into your weekly program. These intervals should be no longer than one minute, so you can maintain a strong and powerful gait.
I call this "strength running." The key is to focus on getting good leg extension with your stance leg like I have in the photo above.
If you do not have access to a steep hill, improvise by using a set of stairs, skipping every other step or even every two steps to get power and extension. Or simply use a treadmill and jack up the incline.
MASSAGE AND STRETCH
To help with the knee discomfort while you are working on the solution, foam roll or preferably do some self-massage on your quads. Then lightly stretch the quads, holding for 1-2 minutes at a time. Remember, this will only help relieve the pain, but will not rectify the problem.
Hope this helps - E
Author of The Cool Impossible