I had a knee problem also, I worked with an athletic trainer,... nothing really worked. I finally found the solution: the knee (and many other running injuries) are created by the running shoes!!! Some people don't have the problem, others do... either way, shoes are a big issue. Further research and I decided to run bare-foot... I actually bought some bare-foot running shoes (the ones I got look like gloves for your feet, they are very light - they are made by Vibram and the model is KSO). I fell in love with them: NO MORE PAIN and so much better to run... (my running posture changed: it is now like what is described in Chi Running - search for this on YouTube). The only issue I had was that at the beginning you have to cut way down on your distance for your muscles to "reconfigure". You are using different muscles (Calves mainly). So you run short runs and build up (with patience) but the result is really worth the effort (I also run faster and much easier up-hill). Of course I am not an MD (BTW: most don't know about bare-foot running :o) but search YouTube and the web for bare-foot running, you will see it is a very big controversy. Good luck.

If this is a recurring pain and has caused you to be injured before, you should see a medical professional.

There are several habits you can pick up to prevent knee pain.

1) Warm Up. Start out running slowly and take 5-10 minutes to warm up your body. Warming up will get the blood flowing and also loosen your muscles.

2) Sometimes, the middle of a run, stop and take a break and see how your body is doing. When my form is off and I'm doing something strange with my body, one muscle will get sore but I won't feel it during the run because of the endorphins. When I stop running, stretch, and move my joints around and stretch my ankles I can feel if there is any soreness. If when you stop you feel some pain, you might change your running form, or run more slowly. If everything's okay, you can continue running.

3) Watch your running form. Make sure when running you are bending your knees even when your feet land, and that your feet always land directly underneath your body, never in front of your body. The goal is to make each step soft, and take more steps so each step is softer and your feet are on the ground for less time. This is especially important to pay attention to when running quickly, because the tendency can be to widen your stride on purpose and with your feet in front of your body, causing it to "brake" and putting more force on your joints.

Here's a video of what you should be careful not to do:

[youtube]iKuHBtw1NOQ&hl=en&fs=1&[/youtube]

4) Do exercises a few times a week to strengthen the muscles around your knees. Squats and lunges are good for this, 2 to 3 sets of 15-20 or more reps.