Ran as a supported training run for a fall ultra. Held close to 12:00 pace only walking through aid stations for as long as possible. About mile 12 started slowing down to 12:15-12:30 pace. At mile 19 had to shift to a run 5 minutes, walk 1 minute with slight variations if I could time the walk to match when I reached an aid station. Around mile 23 shifted to a run 4, walk 1 schedule. Reached 26 miles at about 5:27:30 and realized I could still make 5:30:00 if I had any sort of kick in me. Clock was just changing to that when I crossed the finish line. Since the race was not chip timed I may not have made it officially, but with it taking at least 10 seconds at the beginning to reach the starting line, my Garmin would have had me under if I'd remembered to stop it.