I went to a shop for runners and they put me on a treadmill to see how I run then suggested a shoe to help correct / enhance my running...best shoes I've ever run and the advice and cam thing was free. Guy was a major marathon competitor and gave me some tips on running so that I could run further without knee pain (seems my stride was much too long)..joints don't hurt anymore and I can run almost 2x further / longer than before.
just my $0.02