10 mi total: 20 min w/u, the 8 x (4 min Hard / 1 min Easy), then ~2 mi c/d.
This is TOUGH! My effort on the Hard portions was maybe too hard; avg HR on the last 4 reps was ~158 bpm, with peaks in the mid-160's!
MTA: Avg Pace during the 4 min Hard portions was ~6:30. That's 6:30 pace for 32 minutes, stretched out over 40 minutes. This was probably too much for me, although I wasn't struggling too much DURING the workout. It's also a bit sad that during my 5K time trial a couple weeks ago, I was barely able to manage a 6:29 and 6:30 for the last 2 miles!