My knees keep sounds like cracking

It might be a condition called "chondromalacia patella". I have the same problems and it can be very painful. I recommend you see your doctor as soon as possible so he/she can arrange for you to see a specialist.
In the mean time check out this site for more info.
http://www.medicinenet.com/patellofemoral_syndrome/article.htm
I hope this is helpful.
Mac#

Hi Anonymous

You don't say how old you are, but it may be arthritis or a problem with not-smooth cartilage. If you have pain or weakness or a loss of range of motion you should see a health care provider. That being said, if you do sports that are hard on your knees with things like running and jumping, be sure you are doing exercises to strengthen the muscles around the knees, because those muscles will help hold everything in place to prevent injury.

If your health care provider says it is safe, there are many things you can do to strengthen the area around your knee, thus stabilizing the knee. This page has examples of some of the exercises, depending on your level of fitness and knee issues. http://www.bigkneepain.com/knee-exercises.html

Hope this helps you. Thank you for writing.