RicF I didn't mean 172 was my Max HR typed that wrong 172 is supposed to be my fast training Zone which I haven't tried yet as I've been encouraged to get used to regular threshold pace running and Tempo/long interval session once a week and then I can train in the top zone (think I may collapse in that zone)
Johnas - k's last night not as fast as I can but in HR zone of 162-171 which I don't hit until about 1.20-1.30 (min sec) into rep then it stays at around 166/167 my flat out HR is 172. Having said that I was tired but I put that down to previous 2 days and I don't think I could have gone much quicker last night maybe 1st 3 as felt comfortable but last 2 tough!!
Threshold for me is continuous running Tue 60 mins and Wed 45 mins again in HR zone 150-161