I've had some knee trouble in the past when running. After around 8-10km my knee would start to hurt, even though I was far from out of breath and physically could have kept going a lot longer. Just yesterday I got a pair of Vibram Five-Finger shoes, which are made to be as close to barefoot running as you can get while still wearing shoes, and plan to try them out in the weeks to come. Hopefully running "barefoot" will lessen the load on my knees, and let me run again.
