Treadmill PR vs. Real PR / NW Passage Relay

Yesterday I had the best run I've ever logged on the treadmill. I didn't start off thinking that I wanted to run hard; it just happened because I was feeling good. I ran negative splits each mile, starting with 7:15 and ending with 6:44. I ran my first 3.1 miles (5k) in 21:41. When I got to this point I was excited, since this is fastest than my goal PR 5k time for the year. Maybe I should think about resetting my PR goal? I ended my 5 miles in 34:35; a 6:55 minute/mile pace. I was thrilled that I ran that fast on a treadmill and in general. The only time I've ever logged a mile under 7 minutes was my first mile of my 5k back in September, when I ran 6:55. I wish I had kept track of how fast my last 3.1 miles were - definitely faster than the first set of data I took. I hope this is just the start of a fabulous race season.

This got me thinking, since I technically PR'd yesterday on the treadmill. Does a treadmill PR count as a real PR? My personal view is no - I must run in an official race, wearing a race number, in order for a run to count as a PR. So even though I had my best run ever, it does not count in my mind for a PR. What is your opinion on this? It does give me motivation and encouragement to go out and PR. It is all mental now.

Side note - Is anyone running the NW passage Ragnar Relay with Insulindependence? I think I might sign up. It is a fun race experience (I did Madison to Chicago last year with some people), however, I'd be more tempted if I knew someone else was doing it as well. Let me know!