I've admired people who can run on trails. My local trails are very steep and so the people who can run on them have to be very fit. I wish I could be like them so I've decided to try running.
I have started by running a few miles around town. You would think that someone who can hike 25 miles in a day would be in really great shape, but I am not. Running isn't the same and I get tired much quicker.
I had the pleasant experience recently of feeling like it is getting easier to run. That encourages me to continue. I may be ready to add some more miles or possibly some hills. I find even running through the underpass to be difficult, so hills are definitely something I need to work on.