Heart Rate Q

Tough question to answer easily. If you do enough researching you'll find a whole host of variations of HR zones and how to calculate them. After a lot of research I arrived at my own personal variation that seemed to make sense based on everything I had read. I have 5 zones based on my field-tested sport-specific max HR adjusted for my resting HR. All that means is that I went out and did a 20min test at the track and on my bike to figure out my max HR. I then calculated each of my zone limits after factoring in my resting HR. here is an example of my zones for running based on a max HR of 189 and a resting HR of 46:

Z1 - easy/recovery - <60% = <133bpm
Z2 - LSD - 60% to 72% = 133-149bpm
Z3 - tempo/steady state - 73% to 84% = 150-166bpm
Z4 - interval - 85% to 92% = 167-178bpm
Z5 - Max - 93-100% = 179-189bpm

My aerobic threshold is roughly near the top of Z3. Only way to be sure is to have my LT tested and I plan to do that for my training next season. The basic idea is that you should be able to train in Z2 for 60, 90, 120min without getting that burning in your muscles (from lactic acid). Z3 should require some pushing and depending on where in the zone I am I start to get that burning/heavy feeling after 20-30min but I can make slight changes in my pace to stay on the edge without totally getting in anaerobic territory. Intervals should push you over your LT and that's why they are INTERVALS...you get shorter duration work periods with active recovery between to let your body clear the lactic acid. 800m repeats with 400m jog for recovery would be a good example.

There is a decent thread from back this winter when I was trying to sort all this out for myself: HR zones...AGAIN!