Today I've done a zone 2 run and my fr 255, with the 12.27 software version, said it was a tempo run.
I've staid for 30 minutes in zone 2, and only 3 minutes in the low part of zone 3 (max hr for the run was only 5 bpm higher than zone 2).
The only reason I can think the watch would think this was a tempo run is because I run with a garmin hrm strap that records power and the power zones were left in the default settings, so the power zones say I was in zone 3 for most of the time.
I thought Garmin watches calculated training effect based only on hr zones, not power zones. So do I have to set the power zones in order to receive a correct training effect or is this just a bug?
