I was to do a 6 mile "pace run" today -- 1 mile of warm-up and then 5 miles at marathon pace. Because the treadmill speed doesn't accurately reflect effort, in my view, I just made it 9 minutes at an easy pace for warm-up and then 5 x 8 minutes at a steady/hard pace... 49 minutes in total. I started with the treadmill set to 5.5 for the first 9 minutes. Then I ramped it up to 6.5 for the next 35 minute and finally 7.0 for the last 5 minutes. I felt like I was really truckin' for that last 5 minutes -- much faster than marathon pace.
Actually, when I look at it, my "feel" pace probably wasn't far off. The last time I calibrated the treadmill, I found it was off by 13.1%. So 6.5 miles per hour equals 8.16 minutes per miles. Setting it to 6.6 or 6.7 would get me a couple of seconds on either side of an 8 minute mile. And a 7.0 x 113.1% equals 7:35 minutes per mile, which feels about right. I'll know for next time!
My total "treadmill" distance was 4.81 "miles". Close enough.