knee pain from treadmill

Question
I've been running on the treadmill for quite a while now. When I first started I had pain in my knee but that disappeared after I got new sneakers. About half a year ago I got a new pair of sneakers which brought back the pain again. I reverted back to my old ones but the pain has not only remained; it has intensified. Unfortunately, I've tried other exercises but haven't seen the same results as from the treadmill. How can I alleviate/prevent the pain so that I can continue getting my exercise?

Can you recommend other forms of exercise that would achieve similar benefits to the treadmill?

Thank you!

Answer
Esther, I'm sorry to hear about your pain.  I would be very surprised If I can't help you alleviate your pain very quickly.  Please visit the following 2 websites.

http://barefootrunning.fas.harvard.edu/4BiomechanicsofFootStrike.html
http://www.youtube.com/watch?v=7jrnj-7YKZE

Since your pain seems to be dependent on which shoe you wear it is very likely that it is dependent on what part of your foot absorbs the impact of running and how the foot is positioned.  The previous 2 links that I gave you will show you different foot strikes.  They are often shown without shoes, but can easily be done with shoes on. It is much easier to demonstrate barefoot.  However, I do need to caution you.  This will cause muscles, tendons, and ligaments to work in ways they haven't been.  Only run a half mile the first day when practicing a new foot strike.  Normally you don't feel sore until the next day.  You can't judge by how you feel while running.  

Please let me know if you have other questions or need help with the form.  I can definitely recommend other exercises, but if you enjoy running you need to find a form that will not cause pain in any part of your body.