first of all thank you for writing the article on Heart Rate and Training Zones, very clarifying!
This cycle 5k session was at 3'56 with strong lost km and today's race day i did a 4k trial which i haven't done for over a year :
3'39 bpm 139
3'46 bpm 166
3'47 bpm 172
3'54 bpm 185
Started too fast as I didn't know which pace to aim for. Felt in control until somewhere last 800m. Average 3'46 in 15'06 total time.
Calculated 2k pace session should be 3'55 although i don't think im there yet (last session 4'02 4'03 4'01 3'59 and 3'54)
Ended cycle with bodyweight 74-75kg and resting bpm 48.