I've performed a bunch of tests on hill climbs and descents for me. What I've found is that my:
NGP for climbs = AP / (1 + 6.0 * Grade)
NGP for descents = AP / (1 - 2.5 * Grade)
For example, consider a 10 mile loop with 1400 feet of elevation change.
If I run up a 3 mile hill with a 4.4% grade, at a 10:30 pace, my NGP 8:18.
If I run down a 2 mile hill with a 6.6% grade, at a 7:50 pace, my NGP is 9:23.
And 5 miles is flat, so my 9:15 actual is the same as my NGP.
The overall average NGP is 9:00. That means I get some credit for running hills, rather than all 10 miles being flat. About 20 sec/mile more of an effort.
=====
What I find interesting is that if I didn't know the segment stats, and only knew the bare minimum about this run. That it was 10 miles long, that the overall average pace was 9:20, and that there was 700 feet of gain. I could come up with the SAME NGP. I don't need to evaluate the run as a whole bunch of segments.
- NGP-dcb.GIF (31.68 KiB) Viewed 5461 times
I get that everyone will be different. But the general ratio of 6 -vs- 2.5 for climbs and descents, is probably relatively close for many of you. And the NGP -vs- Actual Pace differential for my climbs and descents feels right using these parameters.