I had knee and back problems every couple of months after getting a new pair of running shoes.  I was 220 lbs and a very heavy footed runner.  I purchased these shoes last May and I still run in them consistently.  I am under 200lbs mostly due to fact that my knees and back do not bother me anymore.  I recommend these shoes to anyone.  You may not be able to dunk a basketball or run like a gazelle from your springs, but they definitely help your aches and pains.