curious.....are you avoiding running due to some knee issues or are you just enjoying biking/rollerskiing as your main exercise......what do you plan to do with running in the future?
It's the knees. When I was assessed, the cartilage was up to 50% gone. I definitely feel them any time, all the time but especially when running. So I am doing what my PTs tell me: listen to your body. Had a lactate profile done on the treadmill today (5/26), I can still run but I do feel them.