CopperRunner, you’ve pretty much hit the nail on the head. I ran 3 years of cross country and track, and my PR was 18:26. I’m a shorter guy, and over the years I realized I was not really a great distance runner and I didn’t ever feel like I was built for it. Everyone else I ran with was tall and skinny. You can argue about body shape and all that in a different discussion but that’s my 5k PR. The first 400m I ever ran in my life was 59 seconds and that was a couple years ago and I still haven’t tried training for it but every now and then I go out and test it, and get consistently 59 seconds. I personally feel like I have so much more potential than I ever did for distance. Thanks for all your replies and I hope this helps a little.