I've touched on this subject before but I think it deserves it's own topic. I've noticed that on runs where I vary the pace during the run (long intervals if you wish) the average pace for the whole run will be correct (not surprising since i calibrate the runs and that part is simple maths) but the pace for the specific segments will be off when i compare it to the GPS-data I get from my watch.
The fast sections are a bit slower than the GPS equivalent and the slower sections are a bit faster. The following is a run with two distinct sections.
Polar data (the average for the whole run is a pace of 5:01 min/km):
RS graph for the same run
Let's look at the two sections. First the slower start:
Now, RS doesn't compute a single average for the section but they are 5:17 and 5:13 for each of the shoes. Polar on the other hand puts me at 5:33, based on GPS, for the whole section.
And now the faster segment (17:22 to 25:22):
The averages from RS are (4:23 and 4:24) and Polar (4:01)
Anyone have a theory as to what can explain the discrepancy? A few things I think might influence the data:
The first part is up-hill, the return downhill (the route itself is 100% identical though I run up, do a u-turn, and run back the same way I came).
The GPS-data contains a lot more variance in the data (a full stop, zebra crossing, for instance). This isn't part of the RS data and I imagine a consequence of whatever data-smoothing algorithm is used in the pod.
The fact that I'm not getting 100% accurate pace data from RS doesn't bother me that much but improving accuracy is in everyone´s interest so I thought I'd create a thread.