I started cycling because of knees issue from running but as I found out after more than 4 years of cycling exclusively (7-8K miles/year), it made my legs weak. Putting on a pack and climbing a mountain would turn my legs into jello. Fortunately, at about the same time I happened to read the book "Born to run" so I went back to running with a change in my stride using minimalist shoes and to my surprise, it works. It has been 4 months running and there is no pain whatsoever. I now a day ride a bit less and on days I run, I also incorporate burpee (with push-up) session into the workout. Overall, I'm in a much better shape for other outdoor activities than before.