[Scott Johnston]

TP uses either your avg HR for 60min or 95% of your avg 20min HR. I suspect your race time was closer to 20min than 60 min.  Notice that 175 is 95% of 183.  If you recall our suggestion for an AnT field test is 45min.  I think your confusion comes mainly from the short duration of the 5km.  For most recreational runners, a 10km is going to be a more accurate test of AnT.

Scott