I'm hoping someone can tell me if this is odd. I've always found biking tough. Recently, I've started stair climbing -- 471 in a set a few times a week.

I was pressed for time the other day and thought I would take my bike out for a quick spin since I wouldn't get to the stairs. But my knees hurt so badly I came back almost right away.

Has anyone else had something like this? Any idea what I've done?

I've dropped more than 30 pounds and must've improved my cardio so how could this be causing me so much pain now? Is it possible biking is something I just won't be able to do?

Were you pushing too hard? Perhaps too high a gear? Is your seat properly adjusted for your height? There are all sorts of possibilities here.

Maybe it's worth going to a LBS (local bike shop) to get your riding position and equipment evaluated?

It could be one of 2 things in my experience. Either your bike is sized wrong for you (my bike is a little small so I tend to hurt my knees with long biking) or you could be trying to go up hills in the wrong grear which I've never experienced but is what they thought was wrong when I had knee problem. For me it also helps to change which part of the foot I'm pedaling with, switching from middle to toe to heal changes where I put pressure on my knee.

It sounds like it could be bad bike fit (wrong size or wrong configuration) for you. I second the recommendation to go to your LBS and get a bike fit done.