The importance of pacing

Ran 4 x 2K intervals last night at the track in 6:39, 6:40, 6:38, and 6:37.  In the first two repeats my pacing was a little inconsistent in the early lap(s). I'd go through the first lap in 76 seconds, slow down (not intentionally) in the 2nd lap to about 82 seconds and then hold the remaining 3 laps at 80 seconds for a 6:39-6:40 2K. I decided to approach the last two intervals differently and force an 80 second first lap, realizing that running the first lap a few seconds faster wasn't doing much to the overall 2K time and probably just making myself tired faster.  Amazingly, I was dead on at 80 second laps for 1600 meters (5:20) and felt like I had still had some fuel left in the tank in the last 400, so I pushed on and finished strong.  I ran 78 and 76 seconds respectively for the last lap of the last 2K repeats. 

This goes to show how important pacing is and that running 1-3 seconds too fast early on makes a huge difference.  For proof, take a look at the below marathon splits analysis of my Hamburg and Berlin marathon.  I hope to apply the lessons learned and run a much smarter race, similar to Hamburg, at Rotterdam.