Starting over

I was skiing earlier this evening on the ski trails near my house and wondered if slogging around the same trail system year after year might be a sign of insanity, or dementia at least. The temperature was 20 degrees, just about perfect for skate skiing and I had the trails to myself. I've skied since I was a kid, mostly around the Anchorage bowl and for the last ten years on the Chugiak ski trails just north of Eagle River.
I was skating up a hill when I flashed back to a similar night several years ago when I was cruising the trails with a friend, walking the hills and stopping at the top of each to catch our breaths. Now, a decade older, it seems like I can cover the whole trail system in the time it used to take me to go 10 kilometers. I'm not sure if I'm in better shape or if my expectations have diminished enough to intersect with my athletic ability. I suspect the latter.