I ran on the river trail this morning with Sasha, and we ran mile repeats with about 2:00 recovery between repeats. We did not push the pace too hard on the first 3 repeats hitting 5:18, 5:17, 5:17. We kept the fourth repeat easy for the first half, and then picked it up the last half mile. I made it through the first .5 in 2:38 (5:16 pace) and then picked up the pace and ran the last two quarters in 1:12, 1:07. The 1:12 felt comfortable, the 1:07 did not. The last quarter hurt, especially since that part of the trail has a slight uphill on it (HR peaked at 184 during this quarter). This gave me a 4:57 for the last mile. We then ran back to Sasha's house to finish 10 miles somewhere between 1:12:00 and 1:13:00.